Talk:Slide rule/Archive 2

Deletion of dead external link
Commented out the dead link to the Mad Slide Ruler --Михал Орела 11:36, 26 February 2010 (UTC) —Preceding unsigned comment added by MihalOrela (talk • contribs)

A person can make a slide rule ...
The "advantage" that "a person can make a slide rule ..." was deleted (with other things) on the grounds that it was "silly", then restored on the grounds that it was not silly, having been used "to demonstrate it to classes".

I suggest that:
 * The ability to make a slide rule yourself is certainly interesting, but not an "advantage". One might make a slide-rule to demonstrate the principle, or as a novelty, but I don't believe it is practical to make one accurate enough for real-world calculations.
 * Making one out of paper or cardboard for novelty or demonstration purposes is easy and requires no more tools than a pencil and scissors. Making one out of wood or metal is possible, with tools, but in reality not likely to happen.

Thus I propose that we should:
 * Keep a sentence that says you can easily make one out of paper or cardboard (with household "tools"), but drop the mention of making one out of wood or metal (requires "real" tools).
 * Move the sentence out of the "Advantages" section, because a home-made slide rule is just not practical for real calculations. I don't know what section it does belong in though.

(The other text included in the abovementioned edits - standardized, used to check electronice calculator - are reasonable, so I think they can stay where they are. It's only the homemade sliderule that I think needs changing.)

Mitch Ames (talk) 03:09, 25 July 2010 (UTC)

It used to be that you needed rather sophisticated machine engraving tools, but I suspect using resist and acid etching you could transfer a printout of a .pdf of the scales rather easily to either metal or wood. The hard part would be the sliding surfaces. (The ones my class made used 250 pound cardstock, logarithmic graph paper (today I'd use a .pdf image of a slide rule), steel rulers for straight edges, drafting pens, and Xacto knives; an hour of work, two digit accuracy.) You don't have to buy everything. (Great test file for a 3-d prototyper!) htom (talk) 14:01, 25 July 2010 (UTC)

My software (http://www.forth.org/novice.html) generates both CNC gcode and PostScript images of slide-rule faces. The gcode could be used to scribe an anodized aluminum slide-rule. Dyed anodization of a dark color would be scratched off to reveal the shiny aluminum underneath. The PostScript would be used for photo-lithography of an anodized aluminum slide-rule. I don't think that it is a good idea to use a pdf image of a slide-rule obtained by scanning an antique slide-rule. You are not going to have adequate precision. If you use my software to generate the PostScript you can then print it out at a professional print shop to get higher-resolution than you would from a laser-printer. Also, with my software, you can customize the choice of scales and the layout of the scales. My software also generates more readable images than the Pickett slide-rules had. This is because I don't put the label directly on top of the associated mark, but I offset it to the side.

The external link to my webpage has now been deleted by an editor named "Dr.K" --- I am currently trying to get the link restored --- see WP:ELN for this ongoing edit-war. Hugh Aguilar (talk) 06:48, 3 January 2012 (UTC)
 * This isn't the place to promote your Web site. (It wasn't two years ago, either.) --Wtshymanski (talk) 07:09, 3 January 2012 (UTC)
 * Good point. I hope this will help end these walls of text generated by this persistent COI/single-purpose account. Δρ.Κ. λόγοςπράξις 07:32, 3 January 2012 (UTC)

What is the purpose of the external-links section except to provide links to external webpages that are relevant to the article topic? Every link promotes somebody's website. This question of what the external-links section is for, is best addressed at WP:ELN. On the other hand, Dr.K has described my software as "arts and crafts," which is belittling the quality of my work, which would be best addressed here. I'm not aware of anybody else who has software that generates both gcode and PostScript, although Derek has software generating PostScript, and you do provide an external link for him. His PostScript is in color though, so it wouldn't be suitable for photo-lithography of anodized aluminum. Hugh Aguilar (talk) 08:45, 3 January 2012 (UTC)

I put the link back in. Dr.K et. al. have declined mediation. The "arts and crafts" criticism seems to have been dropped; we are talking about machining of aluminum, after all. My program is the only software available for generating images of slide-rules with custom scale lay-out in both CNC gcode and Postscript --- this is obviously relevant to the article topic. Hugh Aguilar (talk) 03:55, 7 February 2012 (UTC)


 * As I see it, the real issue is that the link you're trying to add is to your own site, which provides access to software you wrote. That is very generous of you to provide free access to your software. The trouble is that this counts as self-promotion (even though you're not making any money). See, the point is not how good or bad your page or your software is. The point is that (sorry to be blunt) if you're the only one in the world who thinks enough of your stuff to add the link to it, then it isn't notable enough to be linked here. Conversely if your stuff is notable enough, someone else will eventually link to it. In the meantime, see WP:ELNO numbers 4 and 11; also WP:NOTPROMOTION. Jeh (talk) 04:37, 7 February 2012 (UTC)


 * I already read those pages discussing self-promotion; they are saying that links to frivolous webpages (personal pages, blogs, and other fluff) are not allowed. Dr.K had been trying to say that my software was frivolous when he described making a slide-rule as "arts and crafts." This was obviously not true; we are talking about machining of aluminum, after all.


 * It is nonsense to say that the "real issue" is that I'm adding a link to my own webpage. Realistically, every external link was added by the site's own author. They might have used a sock puppet to do it, but it was them. I really don't believe that anybody ever provides a link to somebody else's website that they have no connection with. The only difference in my case is that I was honest and used my own name. Should I have invented a silly name like Dr.A (pretending to be a medical doctor) and claiming to be unbiased? Does such baloney really carry weight on Wikipedia? But honesty is what you hate and fear the most?


 * I think that the point is how good or bad my software is. What other point is there, except quality?


 * Well, one other point is money. In the late 1970s when the slide-rule market collapsed, some people bought cases of slide-rules for pennies on the dollar (or got them for free if they were employees) as the manufacturers were going out of business. Those people are now senior citizens selling their antique slide-rules on eBay to collectors for huge profits. Essentially all of them are members of ISRM (you provide an external link to ISRM's website). These people are vehemently opposed to anybody manufacturing slide-rules again, as this will kill the antique market. I know that Derek is an ISRM member; this is why his JavaScript software emulates antique slide-rules --- he is trying to drum up interest in antique slide-rules so that people will buy them. Over on ISRM I had people tell me that anything I make would be arts and crafts, and would be worthless compared to the real slide-rules that were made by real manufacturers in the olden days. They are just want to continue selling antique slide-rules on eBay that they "discovered" in a box in the attic (it is actually the same people who do it over and over again though). Most likely the people on Wikipedia trying to prevent a link to my software are ISRM members --- they refuse to provide their real names, so they could be anybody --- but why else would they be so focused on preventing any discussion of modern manufacturing?


 * Dr.K refused mediation; therefore his opinion is worthless. Also, --- he previously told me "go ahead and include it," and when I included it he threatened me with a block for doing so. I am going to undo his revert. Somebody who is willing to accept mediation will have to revert it again. Perhaps you, Jeh --- this will be your opportunity to explain how quality is not the point of Wikipedia --- that would actually explain quite a lot in regard to all of those other external links that Wikipedia provides on this and other articles. Hugh Aguilar (talk) 07:22, 7 February 2012 (UTC)


 * There is no requirement that only "someone who will accept mediation" will have to revert your link. It seems to be that you need to make a good case that your link is not self-promotional and that your page is entitled to being regarded as more authoritative than the typical self-published page. You haven't even attempted that. Instead you've just handwaved WP:ELNO points 4 and 11 away; you've claimed without justification that self-promotion is not the main problem here; you've engaged in hyperbole and strawman attacks; and you've attempted to spin two different fantasies to explain that you're being unfairly persecuted... and that's just off the top of my head. i.e. you're not helping to make your case at all. Jeh (talk) 08:42, 7 February 2012 (UTC)


 * I fully agree with you Jeh. First I did not "refuse" mediation because I did not know anything about it and noone informed me that it was going on. If you check the mediation page you will see I did not participate. But this person repeats the same falsehoods  and personal attacks and creates the same walls of text against anyone whom he perceives stands in his way to include his link. Just check the diatribe he left at WGFinley's talkpage. Regarding his blatant falsehood that I allowed him to include this link please check this diff from December 2011 diff; I was not addressing myself to him when I said that the link could be included by another WP:ELN regular, subject to the condition that the ELN regular approved of it. But to no avail. This guy will persist in his falsehoods no matter what. I tried at ELN to further explain this, diff, but again, he comes months later here to repeat the same fantasy.  Δρ.Κ. λόγοςπράξις  15:24, 7 February 2012 (UTC)

Just as a joke, I have provided a link to Zvi Doron's UltraLog website in the external-links section. His software is basically garbage, but Jeh did say: "See, the point is not how good or bad your page or your software is..." Zvi is a permanent fixture at ISRM and has been soliciting money for his project for many many years. Maybe with a Wikipedia link, somebody will actually send him some dough! I'm sure that every member of ISRM will agree with my decision to put the UltraLog link in the Wikipedia article's external-links section --- they like UltraLog because it supports their contention that antique slide-rules have value (typically anywhere from $100-$300), but that any slide-rule manufactured today is "arts and crafts" and of no value whatsoever. — Preceding unsigned comment added by Hugh Aguilar (talk • contribs) 04:04, 8 February 2012 (UTC)


 * Ok, so now you've added "quoting out of context" to your list of fallacies. The reason for  deleting your link to your site under these circumstances was not how good or bad your software is, but rather that your link is self-promotional and it is to a self-published page. As we've said repeatedly your action violates WP:ELNO points 4 and 11. Please note that those points say nothing about the quality of the page being linked. Quality is necessary, but not sufficient for inclusion. And before you tell me "you are changing your story" please note that I have always cited self-promotion of a self-published page as the issues here. Jeh (talk) 14:33, 8 February 2012 (UTC)

Well, Dr.K has nixed the UltraLog link too. If it had been left in, then we would have to admit that quality doesn't matter (UltraLog is very low quality) but that popularity carries the day (everybody at ISRM will support the UltraLog link). On the other hand, if the link gets banned, then we have to admit that quality carries the day and that popularity doesn't matter (which implies that my link should be allowed). Dr.K did choose to ban the UltraLog link (he had to go one way or the other). So what happens now if all of the ISRM members start requesting that the UltraLog link be included? If we ignore them and stick with Dr.K's decision to ban UltraLog, then we should be consistent and also ban the ISRM link itself. If the ISRM member's opinion can't get UltraLog on, then why should their opinion be good enough to get their own website on? If we keep the ISRM link, but ban my link and the UltraLog link, then it becomes obvious that we are banning any link that has to do with making slide-rules (without regard to quality or popularity), and are keeping only those links that have to do with collecting antique slide-rules. All in all, I think that it is unfair that poor Zvi Doron should get banned --- considering that I had nothing to do with Zvi's software whatsoever. Really, the fair thing to do would be to allow links for any website that provides software for making slide-rules, assuming that the programmer made at least a halfway attempt at quality. It doesn't bother me if other people get links to their software, so long as mine does also; I feel confident that a comparison will show my software to be superior to anything else. Of course, this policy would be problematic if this were an article about something like Perl which is the subject of hundreds of webpages. We are talking about slide-rules however; the only people who have made any attempt at writing software to generate slide-rule images are myself, Derek and Zvi. That is three links --- how hard is that? Hugh Aguilar (talk) 12:19, 8 February 2012 (UTC)


 * It comes back to WP:NOT. Wikipedia articles are not: Mere collections of external links or Internet directories. WP is also not a how-to manual (WP:NOTHOWTO). As for your little test and/or joke, WP is not bound to comply with the outcome of your analysis, so spare us the "ah-ha! gotcha!" tone.  We are also not talking about any other links. It is most certainly the case that there are a lot of inappropriate links in a lot of articles here, but that is reason for stepping up the enforcement of link rules, not for relaxing it. Coming back to the link you want to add to your page, please address the points that you are attempting to promote your own site and that your site is self-published. Anything else you write here is worse than a waste of your time: it won't help get your link included, and you are  painting a very clear picture of a single-purpose user who is not particularly interested in working with the community, only in challenging it. Jeh (talk) 14:33, 8 February 2012 (UTC)

For me, and I think most people, Wikipedia is a mere collection of external links. The articles are just fluff, primarily only useful to high-school students who are trying to fake up some expertise on a subject that they know nothing about in order to write a report for a teacher who also knows nothing about the subject. I typically read a Wikipedia article to obtain an idea of what the subject is about, to determine if it is something that I would be interested in learning (mostly programming algorithms). If I am interested in learning the subject, then I go to the external-links section to get some real information from people who actually know what they are talking about. I wouldn't even consider learning from the article itself --- the article's only purpose is to vaguely describe what the subject is about, not to actually teach the subject. For example, a person could read your article on binary trees and be able to write a high-school report several pages long and giving himself the appearance of being a learned computer scientist --- although he has never written a computer program in his life. He is going to turn in the report, then jump on his skateboard and forget all about pretending to be a computer scientist and all of that other nonsense that the teachers require. The same thing is true of your slide-rule article. It doesn't explain how to multiply a chain of fractions, which is a very basic operation. It doesn't explain how to do x^y calculations on the LL scales. It doesn't explain how to do anything. It doesn't give any definition of what these scales are, but instead says that a particular scale is "useful for finding" some function. A high-school student could write a lengthy report, faking up great expertise, and yet be unable to perform the simplest calculation. He is definitely not going to know how to write a computer program to generate images of slide-rule scales, considering that he doesn't know what the definition of those scales are. The articles are just fluff --- only the external links have any actual value for anybody who actually wants to learn something.

As for my site being self-published, of course it is. Every website on the internet is self-published by somebody. I really don't believe that a person can understand something, while yet being unable to create it himself. It is true that all of my contributions to Wikipedia have been adding links to my own website, referencing various programs that I have written (only this one challenged so far). That is because I only claim to have any understanding of a subject if I have written software that simulates it. I would never claim understanding of a subject, if all that I have is familiarity. On the other hand, this isn't original material either --- I didn't invent the slide-rule --- I just understand the thing, in the same way that everybody who has manufactured a slide-rule understands it. Zvi Doron understands slide-rules too (he is not a very good programmer though, as his software generates some rather crude images) --- I would give him a link.

I maintain my claim that every external-link was provided by the site's own author. That is not a "fantasy" --- that is just human nature. Who really cares about ISRM, who isn't an ISRM member? To believe that ISRM is cared about outside of ISRM is the fantasy! It is also true that every website was self-published by somebody with an agenda. At ISRM, the agenda is to promote the sale of antique slide-rules on eBay. My software was written with the agenda of promoting the modern manufacture of anodized-aluminum slide-rules. These are very different agendas --- but both pertinent to the topic. The agendas are not just different, but are mutually exclusive --- modern manufacturing of slide-rules would kill the antique market overnight --- that is why ISRM is not going to support giving me a link, although I support giving them a link (they will support giving Zvi a link though, because his images are so ugly that they make antique slide-rules look good by comparison).

I've already said all of this over on the external-links discussion page, but that got deleted. Repeating myself is just a waste of time. You guys have been faking up expertise for so long, that you believe your own baloney now. I really doubt that you know anything about slide-rules. You couldn't perform the simplest calculation given a slide-rule, and you couldn't write software like mine as you don't know the definition of the scales --- but you still want to be the world's experts on the subject --- you want to believe that your article is the final word on slide-rules, despite being nothing but fluff.

If you "step up the enforcement of link rules," you are going to end up without any external-links section at all, as there aren't any links that aren't self-promotional. This would kill Wikipedia! You are assuming that the articles have some value, but they don't. People only go to Wikipedia for the external-links section, because that is the only part of Wikipedia that has any value --- the rest is just fluff. Hugh Aguilar (talk) 05:06, 10 February 2012 (UTC)


 * Zero external links would not be much of a problem. Newbies trying to rewrite or get around WP guidelines and policy are a constant problem.  Don't take offense at the defense.  Dicklyon (talk) 05:41, 10 February 2012 (UTC)


 * Hugh, it is clear that you hold WP in very low regard. It is difficult to imagine why, then, you are so insistent that a link to your site be included. Why would you want your link to appear on a web site you despise? Oh, and re "repeating myself is just a waste of time" - I take it we can assume that you're dropping the issue? Jeh (talk) 06:49, 10 February 2012 (UTC)

Hugh's Site Link
Hugh has posted another plea on my talk page to include his link and various complaints about editors here and he demonstrates a fundamental misunderstanding of what Wikipedia is not. Hugh clearly has some shortcomings in the communication department, something I have sometimes seen in otherwise very smart, even brilliant people and Hugh definitely appears to be very smart to me.

At first I was pretty dismissive of his pretty blatant self-promotional external link but then I noted his site is already referenced in the article. Also, when you check out his link, especially the actual virtual slide rules like this one for instance, I think what he's done is rather ingenious and more or less virtualizes a slide rule so one can actually manipulate it and get a better understanding of how one works. That would be the ultimate goal for this article I believe. After looking at this I'm not certain if there's anything like that anywhere else and perhaps this would merit inclusion in the article despite Hugh's problems with communication.

As I came to this dispute in an admin capacity I would like to remain as such but I suggest to those of you who edit here to discuss this further and try to put out of your mind Hugh's difficulties and see if there's a consensus to include this or incorporate his material into the article somehow, despite the fact he went about it the wrong way. --WGFinley (talk) 15:39, 13 February 2012 (UTC)


 * What are you talking about??? My web-page isn't already referenced in the article. There is nothing in the addition-and-subtraction section that has anything to do with my software. I have vaguely heard about that technique for doing addition and subtraction with a slide-rule, but it is not something that I mentioned anywhere in my manual or provided any particular support for on the slide-rule images that I generate. Also, that link that you provided was to www.antiquark.com, which is not my website. What the link showed is a low-resolution image of an antique slide-rule that has been scanned in with a common desktop scanner. Software was then written (not by me) to emulate the use of the slide-rule by allowing the user to move the pieces around with a mouse. In the external-links message-board, Yworo said: "A web emulated slide rule that people can play with is interesting. A piece of Forth software that has to be downloaded and executed is only going to be of use to people with a Forth interpreter and most likely only a small percentage of those..." In response, I said: "A real slide-rule is 10 inches long. Computer displays aren't big enough, and don't provide adequate resolution, to display a slide-rule. It is possible to zoom the image, but it is horribly cumbersome to use a slide-rule when only 1/3 or less of the slide-rule is visible. Emulators are worthless." I also pointed out that my software doesn't require a Forth interpreter, or any knowledge of Forth, but it is a stand-alone .EXE program. Now you are crediting me with having written a slide-rule emulator! I didn't write that emulator. I have no connection with the antiquark web-site. I find it mighty amusing that you say I have "problems with communication" --- when you clearly don't know what you are talking about. As for your compliment that I'm "very smart" --- there may be better judges of that than you. lol


 * For the record, this is my web-page: http://www.forth.org/novice.html Download the slide-rule.forth.zip file to obtain the software. Read the slide-rule-brief.pdf file for a discussion of how to use the software. My software generates CNC gcode and PostScript images of slide-rule faces. In both cases, the idea is to build a slide-rule out of dyed-anodized aluminum. With the gcode, you would use a milling machine with a fixed scribe (not a rotating tool) to scratch off the dark anodization to reveal the shiny aluminum underneath. With the PostScript, you would use photo-lithography.


 * I have already said that I support providing links to Zvi Doron's and Derek's sites. Derek's is the antiquark site that you were describing above. He has software for generating PostScript images (but not gcode), but his are in color and so are not suitable for photo-lithography. Also, his images are somewhat crude compared to mine (but they are a lot better than Zvi's). I feel confident that a comparison will show mine to be superior. His PostScript was written fairly recently in an effort to show me up. This has nothing to do with his old JavaScript software that you linked to and which uses scanned-in images rather than generated images. Ask him on ISRM for a link to his PostScript code (I could provide a link, but it may not be up-to-date, so you should just ask him directly). Hugh Aguilar (talk) 20:44, 13 February 2012 (UTC)


 * Self-interest declaration: back in the 1960s I taught Slide Rule 101 (there was no 102 or 201 or ... it had to have a number.) As I've mentioned up-thread, I had students build slide rules from engineering log graph paper and cardboard. I did so initially because I was told to, but after my first class did that, I became convinced that it greatly helped almost all of the students understand and use their slide rules. There used to be a .pdf that would print out on two sheets of USA legal paper a body, slide, and cursor (that used a thread) that was folded and glued that made a reasonable 10" slide rule. (The slide was three layers of paper folded and glued, a snug fit into the enclosing body which was also three layers, front and back had scales; alignment not adjustable, made by careful folding and cutting a very long slot the length of the rule.) Wasn't very accurate, two places at most because of the construction. My parents taught me how to use them, so for me it's almost instinct -- instinct informed by having a slide rule in my hands at a very young age.  I know there were students whose understanding was not helped by the build-a-rule exercise, but those students already were using slide rules. I know that Wikipedia articles are not "how to" (although this article does some of that, it almost has to if it's not going to be an article about the objects some collect!) An external link to a not-for-profit site that offers more details on how a slide rule can be made in the modern world without the factory seems to me to be a worth-while external link. (That is does so using Forth is a bonus, in my mind, but I know my taste for RPN is not universal.)  I've looked for the .pdf I mentioned and can't find it. That would also be a worthwhile external link. htom (talk) 18:25, 13 February 2012 (UTC)


 * The programme proposed in this link, aside from the self-promotional aspects, has not been evaluated by independent experts in a published work. It is therefore non notable and there has been no independent, third-party confirmation that it even works. The evaluation of the technical merits of this programme on Wikipedia, by Wikipedia editors, should be avoided because this is original research. Without external expert evaluation there is no guarantee that the claims made by the creator of this programme are reliable. But even if the claims were true, the stated purpose of this programme, i.e. the use of a better resolution scale for the manufacturing of a slide rule, is outside the scope of this article. Δρ.Κ. λόγοςπράξις 19:34, 13 February 2012 (UTC)


 * I think you are taking this to the point of using it as a scientific instrument, that is not what I'm proposing. I'm proposing the link offers some opportunity for the reader to see how one operates that is far more effective than using many words to describe it. As an example I know we have had to rely on maps that people will create and upload as their own work as using published maps would require licensing them. I see this the same way, it merely illustrates the subject and gives them somewhere to go to build their own. As I said, he submitted it the wrong way by doing it himself he should have gone to this page and asked if it would be useful for inclusion in the article, I'm asking you to set that fact aside for a moment and look at what actually is being asked to be included. As someone who is not a mathematician or an engineer I found the link to be extremely helpful on how they work. --WGFinley (talk) 20:47, 13 February 2012 (UTC)


 * I am not sure we are talking about the same link. The link I am talking about is: slide-rule image generator, which includes a zip file which contains a software-driven slide-rule image generator. The link itself, other than the zip file containing the software, has no information about how-to construct a slide-rule scale. So I don't understand your statement that you found the link useful. Also I can't see how running a programme which produces a printout of a slide-rule scale helps someone understand how a slide rule functions, even if we assume that the programme actually works as advertised and someone is interested in running the programme in the code and language provided. And these are big ifs. Δρ.Κ. λόγοςπράξις 21:47, 13 February 2012 (UTC)
 * No, I totally agree with you about linking to a ZIP archive, that's not the link I would consider allowing. I'm talking about his web app with various slide rules that can be manipulated, it's in my first comment above. --WGFinley (talk) 22:00, 13 February 2012 (UTC)

Sorry all, looks like I mixed up Hugh and Derek's sites, I was referencing things that are linked from Derek's site. I think linking directly to a ZIP archive has many problems and isn't something we would want to do. --WGFinley (talk) 22:04, 13 February 2012 (UTC)


 * Thanks WGF for the clarification. We are finally on the same (web)page. :) Δρ.Κ. λόγοςπράξις 22:09, 13 February 2012 (UTC)


 * Wgfinley: I see the confusion with Derek Ross's site is already addressed. I have to say that your comments would have taken me less less time to respond to—and would not have produced a first reaction of "what the hell? He doesn't know what he's talking about!"—if you had shown more familiariaty with the article and links in question.


 * Please note that Hugh already raised this issue at WP:ELN (see the archive of the discussion here and there was no consensus to add the link to Hugh's page. I feel the responses there by to be cogent and on-point. Hugh has not responded on-point to the issues of COI and a self-published page; at most he says, approximately, "well, my page should be linked anyway" or "lots of other pages are linked, why not mine". Most of his responses center around a conspiracy theory that WP is in league with a bunch of slide rule collectors (ISRG) to prevent the manufacture of new slide rules and thereby maintain the collectors' market value of old ones. Oh, and the absurd claim that all links on WP were added by the pages' authors.


 * Now apparently he has run to an admin for help. My understanding is that this is a content dispute and that admins have no particular authority in content disputes, only in matters of conduct. If Hugh feels he has been treated badly by anyone he should raise the issue at perhaps WP:WQA.


 * Regarding his concern that "how will anyone who wants to make slide rules find my software?" I suggest he do a better job of SEO. It isn't WP's job to promote obscure web sites. As it is, though, if I type the words { slide rule generator } into Google, the very first hit I get is to a PostScript web forum where Hugh is talking about that page and his software, so it isn't all that hard to find.


 * OtterSmith: A link to a PDF that one could print out and use to make a paper slide rule would be very valuable for classes in how to use them... assuming anyone was teaching such classes any more. Hugh's software on the other hand is much less immediately useful. There are no ready-to-use PDFs of the output posted on his page. To use his software, one must first acquire and bring up a Forth environment. One must understand Hugh's Forth code enough to customize it for the specific slide rule one wants to make. Then, to make use of the output, one must have access to a CNC milling machine or a photo-lithography setup; the latter will still require the ability to precision-cut the aluminum rails and slide of the slide rule. I'm afraid I don't see how this link is going to help the average reader understand the article. As for helping someone make a slide rule, sure, but that's a pretty deep level of how-to.


 * Oh, and to use the software, one must also apparently download and read... but let's let Hugh tell it:


 * I'm sorry but this is WP:FRINGE territory. Does this look like a page we should link to, and thereby give credence to?
 * And the closing statement really seems contradictory to his claim that ISRG wants to suppress his software. That does not look to me like a simple case of communicating badly. It looks sadly irrational. Jeh (talk) 23:11, 13 February 2012 (UTC)

How is software supposed to be distributed, other than a zip file? The only other alternative is a JavaScript program that runs in a browser, but that is not going to be very useful for generating CNC gcode and PostScript files for use in making anodized aluminum slide-rules. Those JavaScript emulators, which use scanned-in images of antique slide-rules, are primarily intended to encourage people to buy antique slide-rules on eBay --- Derek is a member of ISRM --- that is why he wrote his JavaScript emulator that you are looking at. You have already told us that you are "not a mathematician or an engineer" (thanks, WGF, for the clarification on your qualification to be discussing the slide-rule article). I don't care that an expert in communication finds a JavaScript emulator "extremely helpful" in learning how slide-rules work --- my target audience is mathematicians, engineers and machinists, or at least people who passed algebra and trigonometry class in high-school (specifically, anybody who is interested in building an aluminum slide-rule) --- that is to say, the kind of people who would read a Wikipedia article about slide-rules.

Jeh is mistaken when he says that my software requires knowledge of Forth. I've already mentioned repeatedly that I provide a Windows .EXE program, and that messing with the Forth code is only necessary for customizing the scale lay-out. Also, I do provide several ready-made slide-rules in both gcode and PostScript. PostScript is just as useful as PDF files, and a lot easier to generate. The PostScript files are intended to be used for photo-lithography, but they could be used for paper print-outs as well. I'm pretty sure that I also already mentioned that my software generates PostScript. I seem to be just repeating myself over and over again.

I was being somewhat charitable when I said that ISRG members had made suggestions that I had sometimes followed up on. That was just various people saying that certain antique slide-rules had the P scale (sqrt(1-x^2)), and my software didn't support it, therefore antique slide-rules are valuable and modern-manufactured slide-rules aren't valuable. So I provided a P scale, which was a trivial upgrade. I'm not a member of ISRG anymore, so the statement that I can be contacted there is obsolete now --- all they care about is selling antique slide-rules on eBay --- I would be a lot more enthusiastic about that if I had a box of antique slide-rules to sell. Hugh Aguilar (talk) 23:48, 13 February 2012 (UTC)


 * Hugh - I think the folks editing here have done their level best to explain the issues to you, you don't seem to grasp them. Heck, I even tried to help you out a bit and you just criticized me for mixing up your link with another one. Wikipedia is not a link farm, is not a software mirror and it certainly is not for advertising or driving traffic to your site. It does not merit inclusion. --WGFinley (talk) 23:59, 13 February 2012 (UTC)


 * Hugh: I'd like to clear up a couple minor misconceptions you have. First, the guy that has the Javascript slide rule emulator, Derek Ross, is a different Derek than myself, the one who has the Postscript code you keep comparing to.  His link here long predates my interest in the topic.  Second, despite your personal attacks and assertions to the contrary, I don't go around writing code just to "show someone up", especially someone I've never even met.


 * As for my reason for writing my particular code, lets just say my goals are orthogonal to yours. You have your "end of civilization" thing going on.  My goals were 1) create algorithmically rendered replica images of various classic designs for documentation purposes; 2) have full control over the sizing of the scale patterns so that if I made any physical rules, I could adjust the spacing to fit whatever I happened to carve out on a table router; and 3) I needed to learn Postscript anyway, so this looked like an easy weekend project to exercise the language.  None of these goals could be met with either your CNC software, or any of the multitude of existing slide rule programs I ran across, which is why I wrote my own.


 * Now, here's some friendly advice. You asked above if there is a better way of distributing your software.  How about putting together a web page describing it, with some screen shots, and maybe a video showing your process on a CNC machine?  Also, fix the sample .ps files with a proper Postscript header (including page size), and convert to PDF so that the average person can view it (not everyone has tools handy to work with .ps files).  You can use ps2pdf included in Ghostscript.  Oh, and also include all the images in one PDF instead of a separate file for each stator / slide side.  That way one can properly see what your slide rules would look like.  Oh, and lay of the personal attacks and paranoia.  Just because some people are not interested in what you have doesn't imply that they are attacking you or your skills.  If someone does show interest, be gracious, but if not, then move on.  As for your attacks on the ISRG list members, and the so-called "antique slide rule market", most of the slide rules I see on Ebay are in the $20 or less range.  I don't think this will be affected at all by anyone making new slide rules (see the Think Geek, or Concise, or Jeppesen CR-3 / E6-B rules for counterexamples).


 * BTW, have you managed to build any of your slide rules yet on a CNC machine? If you need access to one, check hackerspaces.org for a hackerspace club in your area.  But be prepared time wise -- from my calculations, and from looking at various Youtube videos of CNCs in operation, it looks like it would take anywhere from 1 - 5 seconds per each tick mark.  A K&E 4081 has about 6500 tick marks, so that would take anywhere from a couple hours to all day to make one rule. Derekp7 (talk) 03:14, 15 February 2012 (UTC)

WGFinley:
 * I think I grasp the issues quite well. Wikipedia is entirely oriented toward supporting high-school students who are trying to fake up some expertise on subjects that they know nothing about. You are opposed to external links to more in-depth web-pages because these tend to undermine Wikipedia's claim to be the final word on every subject. The Wikipedia editors are just making up baloney on the fly (such as Jeh's claim that my software doesn't come with any example slide-rules) --- there are no consequences for making blatantly false statements, and so this has become standard practice on Wikipedia. I have said before that if you get rid of external links, which are the only thing of value in the Wikipedia articles, you will kill Wikipedia --- and I increasingly believe that killing Wikipedia would be a good thing --- Wikipedia is creating a world full of ignoramuses who claim to be experts-on-everything and who actively block access to in-depth information.Hugh Aguilar (talk) 01:59, 17 February 2012 (UTC)

Derekp7:
 * Sorry about my mistake confusing you and the other Derek. When I said that I support Wikipedia providing a link to "Derek's web-page," I was referring to your PostScript program not to that emulator (although I thought it was a two-for-one deal). Emulators are a waste of time because computer displays are too small and have too low resolution --- besides that, the whole point is to have a physical slide-rule in your hands --- with computers you can do calculations using Python or whatever.
 * I took your claim that writing such a program was a weekend project, to be a put-down of my software. I took about two months to write my program. Most of that time was spent writing support code in the novice package. Even if I had had the novice package already available though, it would have taken at least two weeks (I have 52 scales, which is a lot). You also claimed to know more about Forth than I do, which is not true. And you claim to know "dozens" of programming languages. You are just puffing up your own abilities, but such claims tend to belittle all programmers, including myself.
 * Your #2 claim that my software doesn't support resizing, is not true. Resizing is the primary feature. I have different reduction sets for different sized slide-rules (pocket-size, full-size and large-size). The user has to do more interpolation with the pocket-size slide-rules as there are fewer marks generated in each section. The slide-rules can be generated at any length within reason (don't use the full-size reduction set for a pocket-size slide-rule, as the marks will be too close together to distinguish). You could even use the large-size reduction set for a wall-size slide-rule (door shops have milling machines big enough to engrave doors and these could be used to make a wall-size slide-rule).
 * As for making my software more palatable, I think that what it mostly needs is a GUI that allows the user to choose the scale layout with a mouse. I may yet do that. I'm (slowly) learning Racket for this purpose. My PostScript files do have a header that provides the page size. The problem is that PostScript doesn't provide a standard way to do this, and not all PostScript viewers recognize the header (I asked on comp.lang.postscript, and this is what I was told). GhostScript does recognize the header though, so I don't know why you are having problems (maybe you have an old version of GhostScript). I made the faces separate files to make it easier to cut out the images (notice the corner-brackets that you line up on the paper cutter). Also, the images may get printed out onto adhesive labels, which are not wide enough for more than one face.
 * I have worked as a machinist. A scribe can be moved around much faster than a rotating tool; it would be no more than one second per mark. A laser engraver would be even faster (note: The MiniForth processor that I wrote the development system for is used in the motion-control board of a laser engraver. I also wrote a dxf to gcode translator in Forth for that laser engraver, so I'm pretty familiar with lasers). I still think that CNC gcode is a good technique, especially for large slide-rules, but I also think that photo-lithography is the best technique for mass-production, and that it would also allow for thinner marks which would make for better precision.
 * I do respect the fact that you have actually written software. I don't think that your software is as good as mine, but still, the fact that you write software at all puts you way ahead of the legions of internet trolls who belittle every programmer's efforts but who have never written any software of their own (visit comp.lang.forth for a huge dose of that). Look at my software to figure out how those reduction sets work --- upgrade your software to have reduction sets too, so you really can achieve your #2 goal mentioned previously. Or, better yet, stop trying to show me up and work together with me. You presumably know more about GUI than I do (pretty much everybody does), and that is what my software primarily lacks --- put one of those dozens of languages that you supposedly know to work in writing a GUI.Hugh Aguilar (talk) 01:59, 17 February 2012 (UTC)

We need one special picture
A really frustrating aspect of all nice and large pictures of slide rules on the net is that there's always a cursor somewhere in the middle. That means you cannot take the picture and make a functional computer simulation of this particular model. Besides the pictures are way too small for serious simulation. If I had a nice-looking slide rule I would scan it really large without the cursor and place a link in Wikipedia so that anyone could download it and play with it :)

If you would like to download slide rule software for your computer you should check out the software page Sliderule software on the website for the Sliderule Universe. You can also check out their archive section. Kielhofer 00:23, 2 December 2012 (UTC) — Preceding unsigned comment added by Kielhofer (talk • contribs)

order of magnitude
"Since users must explicitly note the order of magnitude at each step in order to interpret the results..." This is not exactly correct. I have altered the article to clarify the point. WilliamSommerwerck (talk) 23:21, 14 November 2013 (UTC)

Theory of computing category?
The article is listed in the theory of computing category as it is. I am removing this categorization. The theory that slide rules are based on is properties of logarithms so it has more to do with calculus than TOC.
 * Good call. See Calculation. --Guy Macon (talk) 01:49, 15 November 2013 (UTC)

Pro and Con list
So, a Pro and Con, Advantages and Disadvantages, list. Reading the items, some I think are neutral, some biased in favor (or against) slide rules, some biased in favor (or against) calculators, some are just ... huh?

The chain of calculations can greatly influence the results. In general slide rule operations tend to choose chains that are heavy on multiply and divide (and digital calculators and computers tend to be heavy on add, subtract, and add-multiply chains.) Both chains can produce good results, both can produce horrible results. You have to understand the calculation you're doing, where its weak points are, and choose appropriate chains. One of the advantages of slide rules is that when catastrophic subtractions (additions) are performed, they're much more obvious to the user (if the user is watching the calculation results); arranging the calculation chain so that such operations do not occur may produce chains that are multiply-divide heavy. htom (talk) 23:00, 28 December 2013 (UTC)


 * I really think that the banner for pro/con lists is really stating a nonexistent problem here. I simply do not see this list as controversial even though it might seem biased. I think the reader actually prefers the information in this format, rather than a harder to read supposedly "neutral" presentation. I understand why this might be the case for some articles, but for this one this may be the best way to go. Unless somebody comes up with suggestions for better, I would suggest that the banner be removed after a while. Nodekeeper (talk) 21:58, 19 January 2014 (UTC)


 * Looking at Pro and con lists (which is an essay, not a policy), the reasons for avoiding pro and con lists mostly involve controversies. I don't think that what we have is at all controversial -- nobody is claiming that slide rules are better than calculators -- but rather are educational. I think this is a case where a pro and con list improves the article. --Guy Macon (talk) 22:40, 19 January 2014 (UTC)


 * I agree. The banner says the goal is "a more neutral presentation" but I don't see anything particularly non-neutral about this one. Jeh (talk) 23:16, 19 January 2014 (UTC)


 * It's not that I think that the pro and con list is non-neutral (that comes with the banner), it's that it fragments each point and has led to a silly "X is quite bad because of Y"/ "X is actually quite good because people don't like Y" (i.e. tit-for-tat) series of arguments.
 * Compare: "A slide rule requires the user to mentally calculate the order of magnitude of the results... This forces the user to keep track of magnitude in short-term memory (which is error-prone), keep notes (which is cumbersome) or reason about it in every step (which distracts from the other calculation requirements)." with "Because users must separately compute the order of magnitude of the answer in order to position the decimal point in the results, they are less likely to make extreme calculation errors." Well, which is true? Are they both? (Does anyone even have a citation for any of that?)
 * It's quite likely to be somewhere in the middle, a bit of both. Subtle. Nuanced.
 * This pro and con list creates the illusion of black and white. Well, that's just plain misleading. Tomásdearg92 (talk) 01:10, 20 January 2014 (UTC)
 * I have no citations, but I taught slide rule. The errors I saw then and those I see now are of different kinds. Errors then were of students mis-reading scales (or using the incorrect scales) and sometimes an order of magnitude error (usually by mistaking the sign and adding, say, a power of ten when it should have been subtracted.) Today's errors are those of computers doing floating point calculations and students mis-keying parenthesis and other such CAS errors which lead to expression grouping and factoring errors that rarely seemed to occur with slide rules. Students today seem to have much more confidence in their calculation results, rarely checking their own work (and have much poorer estimation abilities as to what results "should" be.) Yesterday's student would be off by a factor of 100 -- and frequently notice that, redoing the calculation -- while today's will be correct to far more digits than the data allow, or off by an unnoticed factor of 2.3 (all of these errors are bad, of course!) "A bad workman blames his tools" is as true of calculators (human kind) as it is of every other kind of worker. The old-style HP RPN (not RPL) calculators seem to me to have been the high point in self-error capture. It's true that computers can do both arithmetic and algebra better than humans, but humans can't proof-read algebra (or LISP) very well, and so don't notice that they've carefully told their calculator the wrong algebra to use. htom (talk) 04:33, 20 January 2014 (UTC)

Right, I decided to reformat the section anyway (WP:BOLD) but didn't change the points. Whether they are sound or not is another matter, but I think they make sense in their new context(s), mostly. Feel free to revert if you don't like it, or even better, edit it. Thanks! Tomásdearg92 (talk) 17:48, 5 February 2014 (UTC)

FWIW 1975 was unofficial end of the slide rule era
FWIW, in 1975 I was in the last class at my (public usa) high school that taught students how to use a slide rule, after that they stopped teaching it. I was also the first person at my high school AFAIK to acquire an electronic calculator. The pain of having an electronic calculator was that teachers would not allow me to use it on tests, because what would I do if the batteries died? It is somewhat ironic that these same schools, that would not allow me to use a calculator, now provide laptops to their students. OldCodger — Preceding unsigned comment added by 63.226.231.210 (talk) 18:38, 3 January 2015 (UTC)
 * Well, young man, at my school we weren't taught how to use slide rules (but we were allowed to use them). We were taught log tables. Thincat (talk) 19:48, 3 January 2015 (UTC)

The c in c log(x)
This page doesn't explain the "c" in c log(x). Obviously a constant, but what determines its value?


 * Any value of c will do. It is the distance between the two  index marks, so it's determined by the length of the wooden sticks that the slide rule is printed on. - Dominus
 * C and D are lengths representing analogically(?) the logarithms of two numbers. Placing their lengths side by side allows the lengths to be added & hence the numbers to be multiplied.  JRPG (talk) 21:50, 16 March 2017 (UTC)

Is it really an analog computer?
I'm not really buying the first sentence. I read the analog computer article linked and it seemed they talked about different kinds of computers. A better term would be something like "tool for calculation" or "calculation aid". Not bold enough to make the change without input given how unsure I am... Erik.Bjareholt (talk) 11:18, 24 August 2015 (UTC)


 * Nevermind, I now noticed the analog computer article explicitly named the slide rule as a form of simple analog computer. Erik.Bjareholt (talk) 11:20, 24 August 2015 (UTC)


 * It really is an analog computer. Fun fact: many years ago we had to run a series of models on an IBM system 360. The program always came up with an answer, but it converged on it ...r...e...a...l...l...y... ...s...l...o...w...l...y... and we had a bunch of models to run. If only we had some way of making an initial guess that was sort of close... We built an analog computer that would always give us a +/-5% answer and often hit it within +/-1%, and it gave us the answer instantly. Using that as our initial guess, the big IBM came up with the final answer at least a hundred times faster. --Guy Macon (talk) 02:00, 17 March 2017 (UTC)

Slide rule invention history - John W. Nystrom missing?
This article is missing something important. How about the patent of the modern engineering slide rule by John W. Nystrom in 1851? This is the earliest patent of a slide rule. See Wikipedia "https://en.wikipedia.org/wiki/John_W._Nystrom" His invention was actually manufactured and sold here in the US in the mid 19th Century for use in business and engineering. — Preceding unsigned comment added by Woofyo (talk • contribs) 18:39, 24 March 2017 (UTC) ‎

"Slipstick"
Is the slang name "slipstick" really notable? 65.123.43.130 (talk) 16:43, 8 April 2015 (UTC)


 * The notability requirement applies to article topics, like "slide rule" here. Individual facts covered by an article don't have to be notable by themselves. See WP:N. Jeh (talk) 17:43, 8 April 2015 (UTC)
 * It was also used in the UK though I have never seen it documented & thought it was stupid. Like everyone else, I lubricated it with pencil graphite. JRPG (talk) 10:29, 17 March 2017 (UTC)
 * The phrase "slipstick" was extremely common in the aerospace industry before the first calculators appeared. BTW, you can still buy one, but it will cost you. -Guy Macon (talk) 01:31, 17 March 2017 (UTC)
 * The term was used frequently by the protagonist of Have Space Suit, Will Travel, a novel by Robert A. Heinlein. Per our article, Heinlein did aeronautical engineering work for the U. S. Navy during WW2; it's likely he used a slide rule then, at least. Jeh (talk) 01:39, 17 March 2017 (UTC)
 * I don't think it's notable. --192.86.0.151 (talk) 00:22, 7 April 2018 (UTC)
 * The slang names "slipstick" and "fiddlestick" are both known in UK. Notability only applies to articles, not to statements within articles. All that matters is whether such statements can be sourced. Narky Blert (talk) 09:04, 5 November 2018 (UTC)

Hemmi / Versalog
(Just ran across this info and decided to leave it here after scanning the article)

The 'Versalog' SR (missing from this article) was very popular in 60s-70s US engineering schools. At the time, bamboo construction was preferred. When the HP-35 came along, it dominated quickly!

"Hemmi Bamboo Slide Rule Company Ltd. in Japan is the oldest and most well known Japanese manufacturing company making slide rules. Jirou Hemmi and Company was founded in 1895 and, in 1912, was granted by the Japanese Patent Office Patent No. 22129 for their laminated bamboo construction method for slide rules." It lasted until the mid-1970s. The 'Versalog' was sold in the US by Post. "Although they never manufactured their own slide rules, the Frederick Post Company was once the third largest supplier in the United States, behind K&E and Dietzgen. Post distributed a wide range of slide rule models, both under their original brandings and rebranded as Post products. Post-branded slide rules were initially produced by a range of German manufacturers, but in 1932 Post selected the Japanese company Hemmi Keisanjaku to produce the bulk of their slide rules from that point forward. By far the most common of these Hemmi-manufactured Post slide rules is the Versalog 1460, a 10' duplex slide rule with 23 engine-divided scales. The Versalog 1460 is similar to a K&E 4081-3 in most respects, and was once a popular choice among both professionals and students."


 * Bamboo was favoured for many things like this, as it expands less with moisture changes than timber does, so avoids the slide sticking. Andy Dingley (talk) 20:23, 15 January 2019 (UTC)

Materials
When I was studying Materials Science at UCLA in the 1980's, I had a discussion with several professors about the applicability of various materials for making slide rules. The general consensus was that slide rules made of bamboo were the most mechanically stable and likely to generate reproducible results over time under the broadest conditions. Professors offering opinions included [George Sines], [Christian Wagner], and Tung Hua Lin. Professor Lin was undoubtedly the single person with the greatest knowledge and experience working with bamboo who ever lived. — Preceding unsigned comment added by 50.1.214.5 (talk) 17:34, 28 December 2019 (UTC)

Popular Culture
♥ In Season 4 of The Avengers, John Steed uses a slide rule... But now I can't figure out which episode! I should have written it down. Damn.

♠ In Season 2 Episode 2 of The Wire, at 31m35s, a slide rule is used by the coroner's assistant to calculate how long 13 murdered girls were able to breathe in a closed shipping container. — Preceding unsigned comment added by 50.1.214.5 (talk) 17:49, 6 September 2020 (UTC)

Gauge Mark or Gauge Point
Mention: Gauge Mark or Gauge Point - Constants or numbers which are used to frequently in calculations marked on the scales of a slide rule to save the user save time by not having to remember the constant or by minimizing repetitive calculations. The most common gauge points are found at 3.14, representing pi, and .785 representing pi/4. Jidanni (talk) 15:16, 13 June 2021 (UTC)
 * https://www.sliderulemuseum.com/SR_Terms.htm#G
 * https://math.stackexchange.com/questions/3019564/what-does-the-mysterious-constant-marked-by-c-on-a-slide-rule-indicate
 * http://www.sliderules.info/a-to-z/gaugepoints.htm

Gauge Mark or Gauge Point
Mention: Gauge Mark or Gauge Point - Constants or numbers which are used to frequently in calculations marked on the scales of a slide rule to save the user save time by not having to remember the constant or by minimizing repetitive calculations. The most common gauge points are found at 3.14, representing pi, and .785 representing pi/4. --Jidanni (talk) 15:16, 13 June 2021 (UTC)
 * https://www.sliderulemuseum.com/SR_Terms.htm#G
 * https://math.stackexchange.com/questions/3019564/what-does-the-mysterious-constant-marked-by-c-on-a-slide-rule-indicate
 * http://www.sliderules.info/a-to-z/gaugepoints.htm

Slipstick?
Have never heard of a slide rule being called a "slipstick". I'm 64. American. Computer game maker. 97.113.139.70 (talk) 16:18, 2 August 2021 (UTC)
 * That's the fun thing about Wikipedia. Evidently not a classic SF buff either, else you might have made the acquaintance of Andrew Jackson Libby.

--Wtshymanski (talk) 22:59, 2 August 2021 (UTC)

Materials
Some slide rules were made entirely of plastic. I bought and used a cheap one in the early sixties, but since I don't have any documentation, I haven't changed the article. --Kdammers (talk) 22:32, 24 December 2021 (UTC)


 * Some all plastic rules, for example the Faber Castell 52/82 D-Stab are excellent. The 52/82 is one of the best values in a slide rule.
 * — Preceding unsigned comment added by 2600:1700:6AE5:2510:0:0:0:46 (talk) 20:09, 17 January 2022 (UTC)

Wernher von Braun
The articles states: "German rocket scientist Wernher von Braun bought two Nestler slide rules in the 1930s. Ten years later he brought them with him when he moved to the US after World War II to work on the American space effort. Throughout his life he never used any other slide rule. He used his two Nestlers while heading the NASA program that landed a man on the Moon in July 1969.[21]"

After discussing this issue in the international slide rule group (sliderule@groups.io), there is a proof that Braun most likely realy owned one Nestler 37; a picture can be found here: https://commons.wikimedia.org/wiki/File:Wernher_von_Braun's_slide_rule_by_Matthew_Bisanz.jpg. There exist movies which show him using a slide rule as pointing device, presumably a K&E. With Braun having been more a manager than an engineer it is unlikely that he used slide rule for regular construction work. Therefor this section is misleeding and I'd change it or even delete it completey. Pandreas68 (talk) 15:48, 19 March 2022 (UTC)


 * As a semi-notable engineer/scientist, you may choose to take my word for it, or not, that at any given time, an individual may use one or another brand/model of tool. I myself did not settle on the HP-15C calculator before muddling about with many other makes and models. It is also not uncommon at all for managers with engineering/science backgrounds to do non-trivial calculations. I often use my Post 1461 slide rule to determine optimal interest rates for time value of money.