Talk:Speeds and feeds

the Formula to determine feed rate section
This should use the standard variables. What is listed will cause confusion.

The standards are Case sensitive

 * n = rev/min - RPM
 * N or Z = number of teeth of flutes
 * D = tool diameter
 * Fz or Ft = Feed per tooth
 * Vc = m/min (cutting speed - tip of tooth speed)

All the manufactures use the same variable names. Insert cutters will at the very least have Fz and Vc corresponding to feeds and speeds.. I've skipped the more obscure ones.

Regarding what redirects to where
I started off doing a minor copyedit on this page but have ended up doing more than I intended, I'm splitting a fair portion of this content off to cutting speed as that is where I feel it belongs. Spindle speed is derived from cutting speed, but cutting speeds and feeds deserve an article of their own, especially from a metalworking perspective.

I'm not altogether happy with the intro and point form layout but I wanted to include woodworking and grinding as they are both affected by spindle speed slightly differently.

I've left the woodworking paragraph in limbo and will leave it up to a woodworker to expand it suitably. &mdash; Graibeard – talk 07:18, 7 September 2005 (UTC)


 * Yeah, I was rather surprised when I put in feed rate and had a red link... definitely a topic that needs expanding.  Bushytails 07:40, 7 September 2005 (UTC)


 * Why not just rename (move) this article to Cutting speed and deal with both spindle speed and feed rate? I'll do the woodworking part.Luigizanasi 06:16, 9 September 2005 (UTC)


 * Done -- feed rate, spindle speed and cutting speed have been moved to the cutting speed page. Spindle speed is derived from cutting speed and feed rate is mixed in with it, so cutting speed won the toss. it took a while to get my head around it but I think it's sorted now. Onto the next project, all going well of course. Feed rate and spindle speed are now redirects, as is speeds and feeds &mdash; Graibeard 12:09, 9 September 2005 (UTC)

Since the article is about both cutting speed and feed rate, I moved it to "Speeds and feeds"
This article is already developed to the point where it concerns both cutting speed and feed rate. Each of those has its own section; but they can also be x-ref'd to each other where appropriate. And they don't have separate articles (nor should they, IMO). So it seemed illogical to have it titled as "Cutting speed" and have both "Feed rate" and "Speeds and feeds" redirect to it. (A little like having "jelly" and "PBJ sandwich" both redirect to "peanut butter".) I moved it accordingly, and revamped the lede to tie things together. The sections below can still treat any one thing (cutting speed, feed rate, spindle speed) in all its glory. Cheers, — ¾-10 19:39, 7 February 2008 (UTC)
 * Is it correct to pluralize them, or should it be speed and feed? Wizard191 (talk) 19:11, 1 December 2008 (UTC)


 * Either one would work, but I vote for "speeds and feeds" because it is a well worn set phrase. — ¾-10 01:31, 2 December 2008 (UTC)
 * That's what I was looking for. I'm no machinist, so I'm not sure what the common terminology is. Thanks. Wizard191 (talk) 03:45, 2 December 2008 (UTC)

Conversion error fixed
I noticed an error in the RPM calculations for Diameter. If one uses the usual multiplier k=4 (Imperial Units) then the Diameter is in "inches", not "feet". I submitted the change. Portknocker 16:12, 30 April 2006 (UTC)

RPM calcuations need to be touched.
I've touched the RPM calculations to be "correct" for english units. Can someone update the section to properly reflect the equations and units to make sense with metric and english? -Scott
 * mea culpa. I've redone the equations as per the referenced book. There was an error when I originally transcribed them. Hopefully all will appear correct now &mdash; Graibeard(talk) 01:21, 4 August 2006 (UTC)

Yikes guys. I think the equations are a tad misleading. The upper equation is the estimate for milling, and the lower equation is the estimate for lathe work. (hence name of "work piece") Scott did edit the lower equation correctly for the "precise" form of the milling equation. Graibeard, might be worth putting the precise form of each out to the right of the equations? (dunno.. just a reader with some ideas. ;-)) Thanks for all the work here btw. Its been great to see this information in a simple consumable form. —The preceding unsigned comment was added by 209.169.110.12 (talk • contribs).


 * Okay, I've reworked it again. I've clarified the definition of cutting speed (at least I hope I have!), added an anology which I believe is on the money (but you never know with anologies), and have provided worked examples of the formulas which should help to clarify the minimal differences between them.
 * I'm not sure why the suggestion that the formulas are for different operations, milling, or turning but it, or similar has been said before in the articles history. I've reviewed the source and checked the nomograms and can only conclude that because I'm using plain HSS surface speeds in the example that this is skewing the perception that things are wrong. Considering that carbides, ceramics and flood cooling has upped the surface speeds tremendously in recent years I can understand that initial reaction.
 * And thanks for the feedback, you're not just a reader, but a contributing reader, that's a big difference in my book, and from there, editing is only a tiny step. &mdash; Cheers &mdash; Graibeard(talk) 07:09, 6 August 2006 (UTC)

SFM for Brass is too Slow
The SFM for brass is too slow. It should be double what is shown. Brass runs faster than Alum - 2011 or 6061-T6. In fact, brass runs faster then all shown in the table. If anyone ran brass at 200 SFM in my shop as a top speed, their experience would come into question and their production output would be doggin it. Advocate4you (talk) 02:20, 17 November 2009 (UTC)


 * Then find a ref that supports a higher SFM. Wizard191 (talk) 14:47, 17 November 2009 (UTC)
 * If you are asking me for a ref, then in that case the whole table should be deleted (if not most of this page) because there is no ref that I can see? Is that your double standard? So I expect you will delete the unreferenced table then? No info is better then BAD INFO. Advocate4you (talk) 00:35, 18 November 2009 (UTC)


 * See WP:REFERENCES and WP:NOCITE for policies on this topic. Because the information is not harmful we can leave it there and just post a refimprove to ask for references. If you know that the speed is too slow then go ahead and remove it. Wizard191 (talk) 14:02, 18 November 2009 (UTC)
 * I see you modified your response from adding a ref to another option of removing the info. So your first answer was a double standard and now you are making a correction. Advocate4you (talk) 18:11, 18 November 2009 (UTC)


 * My answer hasn't changed; it's two different answers to two different questions. Your first question was why its so low; my answer was correct it if you have a ref to support the correction. Your second question was why do I need a ref if there isn't currently one; my second answer was to delete the information if you know it is wrong. Correction and deletion are two different things. Wizard191 (talk) 18:43, 18 November 2009 (UTC)
 * Wrong. Your answer was in error. Should have been, " Change and add a ref or delete the info."  Advocate4you (talk) 19:03, 18 November 2009 (UTC)
 * PS: Re-read my first entry. You make the assertion that I asked a “question,”  I did not.  I made a “statement,” that “The SFM for brass is too slow.”  There is a difference between a question and a statement.  Again, you are in error.Advocate4you (talk) 19:56, 18 November 2009 (UTC)

huh
Having a range for the alloy steels is deceiving in my opinion. Steel grades are not contiguous numerical ranges. Instead, from what I can tell without reading the reference, the point is that the feeds are for low alloy steels, so I propose a change of the row title to "low alloy steels". Then the reader can click on the link and fully understand what the low alloy steels are. Wizard191 (talk) 19:04, 19 November 2009 (UTC)


 * The reference does not call for "low alloy steels." References need to be exact if possible.  The Alloy Steels are A.I.S.I #. They range from 1320 to 9262.  Included in this range is 4140 annealed, a popular metal.  Again, it appears that you are arguing with a reference, and Wiki is very clear that a ref overrules your preferences. Advocate4you (talk) 01:45, 20 November 2009 (UTC)


 * It's not preference, it is for clarity; as currently worded its unclear. Plagiarism states: "If the external work is under standard copyright, then duplicating its text with little, or no, alteration into a Wikipedia article is usually a copyright violation, unless duplication is limited and clearly indicated in the article by quotation marks, or some other acceptable method (such as block quotations)." Our text here on Wikipedia is a synthesis of the references we use. You and I both know what that range means low alloy steels and not high alloy steels, but others don't, therefore we need to make that clarification. This is synthesis. Wizard191 (talk) 14:41, 20 November 2009 (UTC)
 * I continue to object. The reference stands.  Also I am refereing to the words as they are capped in the reference.  If you have a problem witht the reference, then buy the book and look for youself.  Also, again, references need to be exact if possible. This reference does not call for "low alloy steels."  I beleive I read one time that in a letter from JW, that anything withour references should be deleted from Wiki. You are asking to make a change without a reference to suit your personal opinion.  I am reverting my edits.  Again, it seems you are making problems with editors.Advocate4you (talk) 00:34, 21 November 2009 (UTC)


 * Seeing as you are unwilling to budge from your POV, I've requested a third opinion. Wizard191 (talk) 01:12, 21 November 2009 (UTC)
 * You are the one insisting on a POV. I'm simply putting out the info as per the reference. —Preceding unsigned comment added by Advocate4you (talk • contribs) 00:39, 22 November 2009 (UTC)

Third opinion: Hey. First, I've undone the edit that readded the weird capitalization, because it does violate WP:MOS and makes the article difficult to read. Now, as to this "Alloy steels (1320 - 9262)" - I admit that I have no idea what it means, but it seems that Wizard191's objection is having a range there? What's wrong about that? It seems that there are ranges for Carbon steels and others listed. Just trying to get a sense of why it's actually wrong. —  Hello Annyong  (say whaaat?!) 15:05, 21 November 2009 (UTC)


 * The numbers refer to SAE steel grades. The other table labels are perfectly fine because there is a contiguous range of steel grades available (although they are not always commercially available), however this is not true with the alloy steel entry. Please take a look at the table in the article low alloy steel; you'll see that there are distinct alloys listed and that the number range is not contiguous. I feel that if we just rename the title of that row to low alloy steel that will remove any confusion. Wizard191 (talk) 18:20, 21 November 2009 (UTC)


 * Yeah, that seems reasonable enough to me. —  Hello Annyong  (say whaaat?!) 20:19, 21 November 2009 (UTC)


 * The reference calls for a range on Alloy Steels and refers nothing about "low alloy steels." This page is about "Speeds and Feeds."  This is a subject that machinists are concerned with.  Those numbers have a great impact for a machinist to determine the SFM for a material. If a machinist were to be told that it was an "low alloy steel," from my expereince, most wouldn't know what that meant as far as determining an SFM and this is why the numbers are listed.  And this is why the reference calls for this range.  I am backing up my edit with a reference.Advocate4you (talk) 00:28, 22 November 2009 (UTC)


 * Does the reference state exactly that all alloys from 1320 to 9262 are done at 65-120 SFM? Or are you interpreting what's stated in the book? —  Hello Annyong  (say whaaat?!) 05:15, 22 November 2009 (UTC)
 * It is a chart titled, "Alloy Steels," not "low alloy steels." The chart lists the alloy steels from 1320 to 9262 with a range of 65 to 120 SFM. This chart has been used by many machinists throughout the years and is published by an authority: Brown & Sharpe. So as long at the chart is titled "Alloy Steels." I'm sticking with the reference. Advocate4you (talk) 06:29, 22 November 2009 (UTC)
 * I know you're sticking to your reference. That's fine; I just wanted to confirm that what the article says accurately reflects the source. Does the source specifically state that every single alloy from 1320 to 9262 is done at 65-120 SFM, or is it a breakdown of like, 5000-5999 is a certain SFM and so on? And Wizard191, could you maybe find a separate source that says that low alloy steels are done at a certain speed? I tried looking around but couldn't find anything online. —  Hello Annyong  (say whaaat?!) 14:58, 22 November 2009 (UTC)
 * For example, the chart lists the Alloy Steels between 1320 to 9262 starting with 1320 @ 95 SFM, 1330 @ 100 SFM, 1335 @ 100 SFM and this chart goes on like this for 2 pages. All steels listed are between 65-120 SFM...etc Advocate4you (talk) 17:37, 22 November 2009 (UTC)

(outdent) Unless the source specifically states that everything in that table is a low alloy steel, I don't really think we can condense it all into one line that says "Low alloy steels". To do so would probably violate WP:SYN. —  Hello Annyong  (say whaaat?!) 18:40, 22 November 2009 (UTC)


 * Fair enough. Thank you for you assistance. Wizard191 (talk) 02:39, 23 November 2009 (UTC)

fubar?
I am seeing alot of theoretical info here but no real world fact take: "Cutting speed may be defined as the rate (or speed) that the material moves past the cutting edge of the tool, irrespective of the machining operation used — the surface speed. A cutting speed for mild steel, of 100 ft/min (or approx 30 meters/min) is the same whether it is the speed of the (stationary) cutter passing over the (moving) workpiece, such as in a turning operation, or the speed of the (stationary) workpiece moving past a (rotating) cutter, such as in a milling operation. What will affect the value of this surface speed for mild steel, is the cutting conditions:"

pick up any Machinery's handbook and you will see 2 seperate tables for milling and turning because they require different speeds.

no mention what so ever of using depth of cut along with speed to determine a feed rate... this is speeds and "FEEDS" right?

and the SFM table is a waste as it is so vague you couldnt even use it for a guide for a guide... no mention of BHN just bam this is the SFM for any operation "irrespective of the machining operation used"

no mention of how feeds and speeds effect heat and with it tool life, surface finish —Preceding unsigned comment added by Magwulfen (talk • contribs) 06:35, 28 February 2010 (UTC)


 * I agree with your frustration—the ancient problem with the topic of speeds and feeds is that it can't accurately be reduced to one small, simple table, AND YET many a machine operator comes at it from that level, saying "just give me a clue what RPM to use, and I'll go from there by ear and feel. I'm not a scientist who's gonna read the book". The oversimplified tables have some value in life (as described in the previous sentence), but the value *is* very limited. They usually come prefaced with a statement like "this is only a very rough guide", but there will always be people who ignore that "fine print". To tell you the truth, in my opinion, this article should be visibly structured into two tiers: the "adequately detailed, science/engineering portion", and then the "quick and dirty oversimplified shop-floor portion". And that 2-tier structure should be obvious to the user when they land here. The quick-and-dirty part should have a very clear preface that tells the user that "you get what you pay for" (figuratively speaking, i.e., how much time and attention you "pay"—if you choose to use the quick-and-dirty part, you are getting only the roughest of value out of it). There is no point omitting either of those two tiers from this article, because if we do, then random newcomers will always come along and try to force the article to be what they expected it to be. For example, if we have only the science/engineering portion, then someone will come along and bitterly complain that we are all a bunch of unhelpful eggheads. So the "clear 2-tier" idea addresses that. Regards, — ¾-10 16:34, 28 February 2010 (UTC)

Merge proposal rescinded
I had proposed that the article currently titled Surface feet per minute be merged into the "#Cutting speed" section of Speeds and feeds. My reasoning was that cutting speed along the workpiece surface is the underlying concept that is being treated, and the units of measurement (sfm or m/min, inch or metric, G20 or G21) are secondary. They are important and need to be discussed, but they are logically subordinate to the main pedagogical task of just explaining what cutting speed is. Theoretically, if we are going to keep the current structure, then one could logically enough argue that there should be a separate article called "Meters per minute (machining)" or something to that effect. Because if we have a separate article for the inch version then we'd need one for the metric version. But then I thought to look into other analogous cases and I found that "Miles per hour" and "Kilometres per hour" are also separate articles. I think a valid argument could be made that an alternate organization is plausible in which sfm and m/min could be parts of "Speeds and feeds" and that mph and kph could be parts of an article called "Vehicle speed", because the combining of the basic units (miles, kilometres, hours) into a compound unit is kind of trivial; there isn't much to say about it. I can't envision creating "Meters per minute (machining)" and having anything to say except one sentence that links to "Surface feet per minute" and "Speeds and feeds". But my structurist heart just can't summon up the mergist energy to even discuss it any further. Not worth the time and effort (opportunity cost) when it works fine as-is. Never mind! — ¾-10 23:13, 1 August 2010 (UTC)

Confusion
Either I don't understand this or it is not right. Speed is how fast the tool moves. Feed is how fast you move the tool and the material together. I think the author is confusing cutting speed with tool speed. Tool Speed is usually what 'speed' means. — Preceding unsigned comment added by Tomwalz (talk • contribs)


 * I think both you and others understand the general ideas correctly—it's just easier to visualize than it is to explain in words that another person will agree on the meaning of. Both speed and feed represent velocity of one thing (cutter) moving relative to another thing (workpiece). So they both can be described with the words "how fast the tool moves relative to the workpiece", or similar alternate words. The trick is communicating that the movement is happening in more than one direction at once. In other words, there are several different vectors involved. For example, consider a turning tool for (1) external turning or (2) plunging (grooving/necking/parting off). How fast the workpiece's circumference rotates past the tool nose is the velocity that gets labeled "speed". How fast the tool moves sideways into the shoulder is the velocity that gets labeled "feed" for turning. How fast the tool plunges into the bar is the velocity that gets labeled "feed" for plunging. I made a totally awesome drawing to make it clear. — ¾-10 01:13, 5 January 2011 (UTC)
 * Check out my even snazzier pics and captions in the article now. Hope this helps! — ¾-10 05:46, 5 January 2011 (UTC)

External Calculator Links
I've checked both calculator links and they are useless for me. Both calculator use imperial units and cannot use metric. A calculator should be sought capable of imperial and metric calculations (ideally a combination of both: E.g. imperial sized tool with metric measurement system). Metric is preferred for engineering outside of America. 94.193.93.109 (talk) 01:18, 21 February 2011 (UTC)

Just Imperial makes it useless
The majority of the world use metric. This article should at least have both methods of calculating speed and feed rates. In its present form it is next to useless. Perhaps it should be rewritten and another topic/entry created for the rest of the world. — Preceding unsigned comment added by 58.170.87.213 (talk) 12:38, 2 August 2011 (UTC)


 * Well, "next to useless" is really easy to say for someone who didn't contribute any help toward building it. The way Wikipedia works is that there is a total lack of information on a given topic until individual volunteers bother to come build it. Then it passes through phases of decreasing lack (e.g., this article) on its way to completeness. And everyone can come do it, so people who complain that it hasn't been done yet in a way that bashes others' contributions are a bit hypocritical. I'd reply that anyone who doesn't help build Wikipedia themselves is the best example of "next to useless", in the big-picture view. A good effort toward building an incomplete Wikipedia article is *way* less useless than the lack of contribution of the rest of the world who didn't bother to help build it, but *will* bother to complain idly about it, before disappearing again and never bothering to help fix it.  Yes, I *would* like to rework the article to treat metric and non-metric, with the former being emphasized over the latter. However, (1) it doesn't make it to the top of my Wikipedia-editing triage priority list right now, and (2) all of the *concepts* are the same, whether metric or inch; the only thing different is the value of constants, etc. So anyone with a brain who has this article to help them can get pretty far regardless of whether they're in G20 or G21 mode. — ¾-10 02:56, 3 August 2011 (UTC)

Can I suggest a modification to make this simpler and clearer? First the cutting rates are not standard, well at least I am not aware of any, and in most cases cutting rates assuming cutting rates of m/min make it more difficult than not assuming a cutting rate in the first place. So for example, if my CNC machine mills at 20mm/min (which is what I am used to), then it is far easier for me if we stay in base units, rather than trying to figure out what constant to apply. So surely specifying Speed/pi*Diameter is easier to work with than a constant that assumes a particular speed rate (somthing that cannot be assumed). So, given the example in the text 30x1000/3*10 is infinitely easier for me to work out if I am working in mm/min, or m/min or indeed  km/min. I just apply a factor of 10 depending on the units I am working in. It would also simplify the examples as well. I suspect this is the real source of the problem with this article.


 * Oh, OK, I think I see where you're coming from now. Actually, the article isn't wrong, but it's incomplete. If its present content were removed and your suggestion replaced it, the article would not be complete—but what we ought to do is present it your way first, and then get into conversions. It's currently geared too much toward common assumptions made in commercial machining, and it doesn't explain those assumptions. So for someone learning about machining outside the commercial context, it doesn't have good pedagogy yet. I think if we fix that, we fix the underlying problem that you put your finger on. Below is an explanation of why I say all this.


 * Meters per minute (m/min) and surface feet per minute (sfm) (rather than mm/min and inches/min) are in fact widely prevalent standards for how to present surface speeds (which is what machinists are referring to when they say "speed"). If I get you right (pretty sure I do now), a big question in your mind at this point is, "If we talk about feed in mm/min (which you're right, we do, for example, 20 mm/min feedrate), then why would we talk about speed in m/min?" The answer is that it's simply a conventional/traditional norm in the machining industries. (And the probable reason for that is mentioned below).


 * Here's a part that I think you already know, but just bear with me. Looking at surface speed, if you measured how many millimeters your endmill's periphery traveled per minute as it was spinning around, you'd find out that it's a huge number of millimeters. For example, a 10 mm DIA endmill spinning at 1200 rpm is giving you a surface speed (what machinists call speed for short) of 31.4 * 1200 = 37680 mm. Rather than talk about "thirty-seven thousand millimeters per minute" (which would be completely rational, no question) there's a widespread convention in the machining industries of speaking instead of "thirty-seven meters per minute". For example, if Sandvik is selling you a face milling head and inserts, they'll talk about speed in m/min and not mm/min. (Or, if you're a bloody American, sfm and not in/min.) It's just conventional/traditional.


 * Now take that endmill that's spinning at 1200 rpm, giving you a speed of 37.68 m/min, and start feeding it laterally into the workpiece. You're right that the standard, conventional way to refer to that feedrate is mm (not m) per min. Say, 20 mm/min. I think the reason why is similar to that discussed above—people would rather think (and speak) in terms of 20 mm/min than 0.020 m/min. Just like they'd rather talk about the aforementioned 37 m than 37000 mm.


 * When I replied above yesterday, I actually spouted off short-temperedly before re-reading the formulas, which I haven't looked at in a long time before just now. I found upon revisiting that they are actually already better than I was remembering, in the respect that they already are presented completely parametrically before they are re-presented with constants applied. So part of what I was thinking yesterday that we still need to do yet has actually already been done. But that doesn't address your concern. Your concern was actually that we should move from all-parametric (first) to all in terms of millimeters (second). That's logical from the viewpoint you're coming from (having been unaware of the m/min standard). But what we actually should do, if we're going to make the pedagogy better, is present it your way first, all in mm, and then introduce the existing content after that, and explicitly explain, in so many words, "OK, reader, you're with us so far, all in millimeters; now let's talk about the next step, which is putting it in terms of m/min (per industry convention), and then, after that, we'll explore an imperial example, and we'll talk about an example all in inches, and then we'll talk about putting it in terms of feet (for the sfm figure, per industry convention)." I think this is what would address your critique (solve the problem) while also not giving up on talking about m/min and sfm, which an article on this topic does need to include in order to be complete/"professional"/whatever.


 * I may take a shot at revising and expanding along these lines soon. I think the spirit might move me to do it sooner rather than later. Not positive, but I feel motivated at least at the moment.


 * Thanks for your patience in explaining further, and in helping to identify the room for pedagogical improvement. — ¾-10 22:57, 5 August 2011 (UTC)


 * I think you have captured it very well and was not aware of some of the intricacies and industry practices.  I look forward to your improvements.  Agree, my first reaction was a bit over the top!  — Preceding unsigned comment added by 58.170.87.213 (talk) 02:49, 6 August 2011 (UTC)

Relationship between Feedrates and Depth of Cut
Does anyone know what the relationship is between the Feedrate and depth of cut is? The Metal Removal Rate (MRR) is given as

MRR = Feed Rate X Width of Cut X Depth of Cut. Speeds,

and therefore the Fee Rate could be implied from MRR/(Width of CutxDepth of Cut), but then what are standard values of MRR?


 * I am a little rusty on the formulas, but the concept is volume of metal removed per unit of time. (Forgive me if that's already known.) I do remember reading in dated references that the units frequently used in the U.S. decades ago were cubic inches of metal per minute. I wouldn't be surprised if nowadays U.S. engineers at companies that build machine tools or make cutting tools work in SI units like the rest of the world, because the business is so extensively globalized now. Probably cubic centimeters per minute I would guess.


 * As for re-deriving the formulas on one's own, it seems to me that a distinction can be made between formulas depending on whether feed is being measured in terms of per-revolution (G94) or per-minute (G95). If the former (G94), then you need all three—feed, speed, and depth of cut (DOC)—to figure out the volume being swept through (turned into chips) per minute. The archetypical example of this case, in my mind, would be turning, where feed is usually measured per rev. But if the latter (G95), then it seems to me that speed becomes a semi-independent variable, because if you know DOC and feed, then that alone gives you volume per minute. The archetypical example of this case, in my mind, would be milling with an endmill on a vertical mill. If you know the DOC in the -Z vector, plus the DOC in terms of what percentage of the endmill's diameter is in the cut, plus the feedrate in mm/min, then that alone gives you volume of material removed per minute, and any speed within a certain range could be used, as long as it was decently matched to the conditions.


 * Hope the above is of any use. I must admit it is easier for me to think about it casually/physically than to express it mathematically. I need more practice in that department.


 * PS: I was going to recommend a reference work like Machinery's Handbook, but you probably already thought of that and may be looking more for costless learning resources. This 1914 edition of American Machinist's Handbook is public domain via age (copyright expired), and may possibly be interesting. — ¾-10 03:58, 9 August 2011 (UTC)

Woodworking fast and slow backwards?
The article states, "In woodworking, the ideal feed rate is one that is slow enough not to bog down the motor, yet fast enough to avoid burning the material." Isn't this backwards? Shouldn't it be, "In woodworking, the ideal feed rate is one that is fast enough not to bog down the motor, yet slow enough to avoid burning the material."? —Anomalocaris (talk) 00:52, 21 September 2012 (UTC)


 * Nope, it's correct as-is. As you increase feed (all else staying equal), you tax the motor's power more, because you're trying to cut a higher volume of material per time unit, which takes more work/energy per time unit (more power). On a typical wood lathe, the motor is not that huge, so you could tax its ability to resist stalling. (If you were turning your wood table leg on a 60-hp CNC metalworking lathe, then the needed power would be available.) However, if you feed too slowly, then you're essentially holding the tool in place while the same portion of workpiece rubs against it repeatedly as it rotates, which leads to friction heat, and you can char the workpiece, just like rubbing sticks together can kindle a campfire via friction. — ¾-10 01:43, 21 September 2012 (UTC)

reference 9 is a dead link
The smithy site still exists, but the page is 404. a quick look at the web site shows they have redone there machinist guide documents but i cannot find an obvious alternative to the linked page &mdash; vulcan_ (talk contrib) 20:29, 8 May 2023 (UTC)