Metal Lathe Tutorial 21 : Speeds & Feeds

This is Lathe Skills, a multi-part series to help you learn basic machine shop work. Exclusive videos, drawings, models & plans available on Patreon!
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[@75Bird455]

A King George's thumbs per fortnight to SFPM conversion chart would be great. Thanks! Also, you're the first person I've EVER heard refer to hardness as BHN, as most mention Rockwell. Having taken tens of thousands of Brinnell hardness readings (by hand) I appreciated it! Excellent video as always!

[@Blondihacks]

So goes the Big Book, therego I. 😬

[@robbystokoe5161]

Assuming 1 King George's thumb == 1 inch, to convert from KGTPF to SFPM, divide by 241,920.

[@Blondihacks]

@@robbystokoe5161 This is the finest comment anyone has ever left on one of my videos. 🥳

[@MaxWattage]

@@robbystokoe5161 I'm currently bracing myself for when I am forced to convert my machine tools to use these units after Brexit.

[@bostedtap8399]

Spot on ref BHN.

[@seven6twomm]

Reminds me of when I was back in machinist school. Speaking first from the perspective of manual machining. We toiled away in the classroom learning and applying feeds, speeds, and depth of cut applications to many machine tool operations, must have done numerous problems on paper using Machinery's handbook, various charts, graphs, formulas. The school did a fantastic job of scaring the shit out of you leading one to believe that if you did not apply the correct conditions to the machine and part being produced, that the world would instantly implode. Then the day came when we stepped out on to the shop floor to apply that knowledge for actually making real parts. This older instructor named Ron, old school machinist mate from the Navy from a century ago, LOL, stated it was important to know where to go and how to figure out the math, but now this is how you really do it. He then proceeded to explain we had to remember three main things: capability/condition of the machine, tool bit profile and sharpness, tool bit position - that was it. He demonstrated various speeds and feeds on various materials and sizes, with various tool bits., explained to us it was all about feel, sound, and appearance of the cut. If you are not feeling the machine, feeling the cut, hearing what it's doing, and can't see what's going on with your cut, then you will never be a real machinist. It was all about what was practical, less on the real math from the book. Went through the rest of the program employing his advise in the shop, only doing the math application on paper for assignments and exams. I'm just a machine tool hobbyist now days, but his advice is exactly how I run a machine. New Castle School of Trades 2000-2003.

[@eddietowers5595]

WOW, of all the people I tried to train in feeds and speeds when I was machining, yours is the most succinctly comprehensive explanation of this subject. I wish I could’ve explained it as you did, to my trainees, I’d usually get slack jawed looks of being lost. I could swear one kid drooled while I tried to explain, in the way I was trained. Great video, Very informative. 👍

[@yorinov2001]

feed a man a fish and you have a kitchen to clean. - teach a man to fish and you get your weekends free...

[@VOAOURKZ]

I just got done watching the lathe and the mill series. I wanted to say thank you! I accepted a tool room machinist job last fall and have already learned way more from you than my actual trainer has taught me. Thank you!!

[@TellURide447]

Do you know what the Yamaha emblem represents?

[@fepatton]

Great explanation of a tricky topic! I want you to know that because of your lathe and mill series, I have cleaned off my mini-lathe and resurrected my micro-mill, which was getting rather forlorn. It's now all tuned and trammed up and has a new precision vise. Thanks for the inspiration!

[@Blondihacks]

Awesome! Glad I could inspire! 😁

[@ninthm00n]

Thank you Quinn. You have an affinity for breaking down subjects and making them entertaining and enlightening . #Saturdaysarefunagain

[@estoncoe5160]

THANK YOU, A ACTUAL EXPLANATION!!!!! Wow those charts really threw me off!! Thank you for giving a truthful insight into the topic!

[@reamer1363]

Quinn, i love the way you explain things. You should be labelled a hobby Machinists Legend, you would win that award for that definitely. And with that experience teachers us experience.

[@firebird8600]

I'm going to have to watch this again after I have a lathe... it was well put out, and able to be understood, but I save money slowly, so I will probably forget.

[@robertoswalt319]

I often save videos like this for future reference. They have come in handy many times.

[@MyTubeSVp]

Subscribe to the channel, and the videos will be with you forever (or as long as Google sees fit ... 😉)

[@gabrielbonannoo]

thank you so much. I have tried again and again to make sense of the calculators on the internet, and confused my self trying to use the handbook. What I really wanted to do is use the handbook! Thanks for showing us how.

[@zanep2689]

Ive spent months now trying to figure out what the diagrams and numbers meant on my (very) old craftsman metal lathe. Every guide I looked up was more numbers and units that really didn’t change my understanding. There was never an explanation of what the numbers meant. This video saved me. Thank you.

[@albarnabas8666]

I love your videos. Very educating. No nonsense. Very straightforward. Easy to digest. Thank you and happy new year.

[@clintchapman4319]

Nice video! Lots to learn when it comes to feeds and speeds, and so many variables... Anyhow, nice work! Keep em' coming!

[@AmericanMakerCNC]

My brain hurts. 😂 Lots of great info. Great job! I'll be watching this video again .... and again .... and again .... and again. I am loving this entire Lathe series and I don't even have one yet. Hopefully soon. I'm almost done with this playlist. Then it's time for the Mill series.

[@MrSmeagolsGhost]

The Adam Booth nod was well done. Gave me a giggle

[@IBWatchinUrVids]

if you like larger machines, don't miss Brian over at his channel, bcbloc02

[@dwegmull]

I can relate as I often make parts that are thinner than some of chips he produces!

[@kanmeridoc1784]

I most certainly did pause the vid and went back frame by frame to see the chart XD. With a safety reference I'm gonna watch the rest of the video now. Your videos have really been a great help to getting started with this, I'm constantly taking notes and printing out pages. I'm nearly to a machinists handbook now.

[@terrinewman7390]

Quinn, my new to me "40's era lathe is broke down getting its first goog cleaning in 20 years! So it's a work in progress for now but keep the video's coming !!

[@griplove]

A lot of information at a mostly easy to digest format. Well done, and thank you. -Joe.

[@davemason6273]

Very well put across Quinn, nice work.

[@zblprojects9753]

Great addition to the series

[@Just1GuyMetalworks]

Great video, Quinn! Not many of these tutorials really give a good "rule of thumb" for the tool radius vs travel. Thanks😊!

[@falconsinput2226]

Hey Quin, your attention to detail in theory and prac is perfect. I’ve just got my first 1973 old school vertical mill and love all your videos 👍🍺

[@unclebobsbees4899]

Love the explanation about Machinery's Handbook. Was always a little confused about some of the charts/calcs.

[@mrpdude84]

First time I've ever had the privilege.... First! Thanks Quinn! Keep em coming! Love the content!

[@lyndone.2682]

I'll be watching this several times.... great video, very instructional!

[@mxcollin95]

Great tutorial! As a fairly new home gamer at machining, I haven’t gotten very far in this aspect of machining yet. I’ve looked in “the good book” as people refer to it (Machinery’s Handbook) but holy crap there is a lot of technical info in that thing, so thank you for digging in that thing for us and breaking things down so well!!! Really enjoying your content and am learning a ton! 👏🤙

[@Blondihacks]

Yes, that book is difficult as a learning resource! Check out my Anniversary Q&A for some better beginner resources.

[@JeremyWilson]

Learned a great deal from this one video. Subscribed. Now processing data.

[@carlosalmeida4415]

Thanks for the info. I would be lost without this.

[@richardmeyer418]

Thank you - that was perhaps the best explanation I've seen to date. Also explains just why the Handbook is so wrong for hobbyists.

[@ALXG]

The most beautiful machinist's nails I ever saw :)

[@jonnyphenomenon]

I need to watch this one again after a good night sleep. This was a lot to take in.

[@willemdafuq]

I just got a lathe and this really helped!

[@howder1951]

Thanks for the info, something I had never formerly address due to the difficulty of it. Instead I learned feed and speed by the seat of my pants, which unfortunately resemble the fit of a skate boarder. Keep it up, and I will keep watching , cheers!

[@Blondihacks]

That’s how most of us learn it, I think. Hopefully this video will help someone skip that part. 😀

[@andrewh2341]

Excellent breakdown of the topic

[@danielpirone8028]

Another fantastic video! Calculator app purchased.

[@DesOwen]

Excellent Quinn

[@RickRabjohn]

Hey Quinn - another well done and fully packed video. Lots to think about and digest. Good to know there is more than just "400 / Dia. Of Stock" for lathe speeds......

[@randynovick7972]

I don't know that I found it useful, necessarily, since I have no machine shop.... but I did find this episode FASCINATING. It sent me down an internet rabbit hole of (on one hand) tips, tricks and rules-of-thumb and (on the other) very frightening dissertations about materials, physics and computation. I still have the chills after two cups of tea. Was the this the Halloween episode?

[@p3astar378]

Good job tackling a tricky subject Quinn - take home message: As your average hobbyist you need to work out what your tools can manage and do well - and then write it down! No point blindly using numbers that were calculated for machines that turn wheelsets for rolling stock or the like. Leave that up to Adam.

[@HWolfpaws]

Really useful video. I always looked at those charts as i would at a red balloon during rain. If it s explained in a manner like this it s really easy. Thanx. Math is actually really useful in most production processes. Thanx

[@HWolfpaws]

Btw could you maybe shout out few speeds maybe for gold alloy, silver or tantalum? I can t find those anywhere.... :(

[@johncooper4637]

Thanks, I didn't know about the other tables.

[@RacerX-124]

Great video, thanks! It has been a while since I've done this.

[@web3036]

New subscriber here, Im on like the 12th video of your channel and I really like How informative and how you explain things. Thank you!

[@stevesteve6545]

Thanks to you , I now have “tappy tap tap” in my head every time I tap a workpiece down in my vise. Thanks a lot.

[@TandaMadison]

Haha got a good laugh at the MEH from Adam. In the machining safety class I teach, inevitably a young mechanical engineer will ask what the numbers on the power feed mean.

[@Blondihacks]

Spinal Tap’s power feed goes to 11.

[@TandaMadison]

@@Blondihacks In case you need just that one more.

[@andyZ3500s]

@@Blondihacks that is so funny --- when you said something like the ten numbers don't mean anything that's the first thing I thought of. Great video by the way. You have a real gift for teaching.

[@PhaseConverterampV]

Brass and bronze also have a unique method of bulk material removal that reduces chip spray. Use neutral rake tool, bury it, as much as your machine can turn, light feed, 1/2 recommended surface speed or less. Works well, place a deflector above your clamped tool. It’s normal to bury full side of insert with this method. Good vid, cheers

[@bailey3668]

Thank you for explaining that.

[@georgesg10]

Good show, I learned in school to use the same formula , You answered the question why the machinery's handbook has different speeds and feeds , The SFPM I learned for steel is an even 100 , I have similar numbers for other metals from school This is a Guide THIS IS A GUIDE THIS IS A GUIDE My mistake is to use lower speeds not always good , After my course I used the formula a lot for turning ( Dia. of the part ) Drilling ( Dia of the drill ) Milling ( Dia of the cutter ) Today I play it by ear sometimes I will still use the formula ....

[@tribsat100]

This just took all the fun out of my new lathe. I bought it for recreational use to escape the complexities of work life balance. I will do it by trial and error it hasnt failed me yet. Maybe I,m in for a culture shock. 😅

[@JonBanquer]

You mention what a CNC shop does for feeds and speeds. Tooling manufactures recommendations, Machining Data Handbook and later HSM Advisor were my go to sources for speed and feed. Looking at the chip, sound and surface finish was what I used to dial it in.

[@cannonroberts5129]

Great explanation

[@rickpalechuk4411]

And only one MEH from Adam :)

[@DavidLindes]

2:54 had me laughing. Sooooo on point. :) Though, don't forget the sigh at 4:02.

[@williamlodato2147]

Love you videos. I’ve always gone with 1/2” steel at 600 rpm. Double the diameter and you’d halve the speed. Halve the diameter and you’d double the speed For aluminum double these speeds and for stainless steel halve the speeds. High nickels and super alloys go carbide and get a good book. I’m a welder by trade so I do mostly rough work.

[@6milesup]

I was just looking at the Machinery Handbook speeds and feeds. Scratching head asking "what-is-all-dis". Lo and behold (or is it beholden?) Blondie has a MH29 open on her bench, which is the same edition as mine. THEN, beyond all reasoning, including King George's reasoning, she shows me a PM1022 lathe. Holy fortnight George, that is the same lathe as mine. Are the planets in retrograde? They shalln't be I shall say. Anywho, thanks for the vid. New subscriber here.

[@rays2877]

Your explanation is the first I've heard or seen for depth of cut and feed rate. You make it simple. Why the 'ell didn't the instructors in the pre-apprenteship course pass on the use of MHB tables ? The course was machinist/millwright. Thank You. You are a great help. I'm just an old retired millwright learning a new skill.

[@Polynuttery]

Nice video !

[@OldtimeIronman]

Of course if you really wanted to be mean, you could always say you used three-fifths of a millimeter per rev on walnut sized stock. But then, I'm proudly weird like that. Good video! The hobby scene needs much more of this!

[@paulmorrey733]

Thanks Quinn

[@daltonmcillwain8600]

I liked the Abom79 pic lol. He’s definitely I deep cuts kinda guy. Love the videos!

[@jimrichey5919]

Playing with the numbers as you put it.. I had a job that required I turn a 12 inch long x 2 inch diameter shoulder on a hand full of 5 inch diameter 1018... best cut vs tool life I got on my big old monarch was a 15 thou feed, .375 depth(3/4 on od) and 300 rpm... chips were wicked, but I got 2 parts per tool sharpening

[@Halinspark]

I was taught that the Machinery's Handbook numbers are more like "do no exceeds", but that may have also been a factor of it being an Intro to Manual class and him not wanting us breaking tools at 2000+ rpm. But he's been doing it for 50 years, so if he gave us numbers, we didnt argue them.

[@dannyrc223]

Thank You

[@williamspiret1]

Hi Blondiehacks, if you have not read the book "The Amateur's Lathe" by LH Sparey, you should, in-fact every amateur should. Originally written for model engineers it is packed with information on the use of this class of lathe. Really useful information is in that book! It also has some machine drawings to make useful add on's for your lathe to increase its capability (Eg. collet set). Line boring, milling, reamer making, lapping, heat treatment, spring turning, spinning are just some of the topics covered. PS. He discusses a technique obtaining a very high finish using HSS, and it is not using the shear tool, although I think it is mentioned somewhere. Good quality content. Keep it up!! Cheers.

[@Blondihacks]

Thanks for the tip! I will look that one up.

[@johnrobertson2749]

Thanks for the tip as well, I've just ordered the book - cost just under $20CAD, well worth it I expect!

[@kaijin2284]

I really like your tutorial. It has made a lot of questions i have had for the past few years in my experience of using a lathe machine. I still have one problem. If the material ex. Metal rod. Was bowl shaped. Is it possible to get a nice surface finish? Material is an aluminum bowl

[@billbaggins]

You only broke my brain a little bit. My lathe restoration is very nearly done so I'll rewatch this a few times. Then it will be time to get some potato's and make some chips.

[@jimstamper7062]

thanks Quin...

[@robertpearson8798]

As a hobby machinist working on hobby sized machines my general rule of thumb is, if it sounds good and it feels good and it looks good, it is good. When time isn't that important I think cautious trial and error is probably the best option.

[@ryanjacobis737]

Good video

[@reinierwelgemoed8171]

This is a great video and what i was looking for. One question though. Im building a desktop type cnc lathe for making chess pieces out of aliminium and brass. If I direct drive my spindle from my 3hp 220v AC servo motor i only have 2500RPM. is that good enough? I can build a gearbox to got to 5000rpm if needed but that is alot more design a fab work.

[@rfsn]

Thanks Quinn, I have 40's era lathe with a top speed of 340 rpm, now I can over speed it with the vfd at a loss in hp I believe, any tips for a slow machine as all the rpms that are mentioned are way faster then I can achieve.

[@stevenfletcher185]

nice effort , thankyou.....

[@tonydeleo3642]

Great video, I have watched the series and I do not remember you covering steady and follow rests. I am an old guy, may have missed it. Thanks

[@Blondihacks]

I have a recent video on steady rests and this series is not complete.

[@7tuben]

Thanks for this nice information. One question, or comment: Regarding the true surface speed beeing the result of the two vectors, the horizontal vector as a result of feed speed has to be miniscule in comparision to the rotational vector. It will therefore add almost no extra surface speed. At least that is my understanding, willing to be corrected. Thanks.

[@Dancer148]

Thanks for the speeds & feeds numbers for some metals. How about plastics, any idea for those? Nylon, Polyoxymethylene (POM), etc.?

[@mathman274]

This is cool, now I have an idea where or for what to look. I know nothing about machining. I was given a benchtop/mini lathe and mill. I fixed all the electronics, built a controller (linuxcnc) etc, but when it comes to actually making stuff I'm clueless. Most time I waste on, what material is best to make this thing I want out of, what cutting tools/mill to use etc etc.?, This video helped quite a bit (usually when trying something on one of the machines, I figure when it makes more noise than my ex wife, something must be wrong... and go from there)

[@marcmckenzie5110]

Quinn, would you do us all a favor and rewrite and condense the big book for home hobbyists? Leather bound on vellum would be nice. It wouldn't take you but a weekend or two! 😜 Very nice job on this segment - thank you!

[@richardmeyer418]

Leather made from the skins of our enemies? :)

[@VectorNodes]

Awesome video find. KZbin needs to recommend more knowledgeable women engineers. This def surpasses most channels I've found

[@askquestionstrythings]

I do not look forward to needing to convert all the feed rates on an old artisan lathe as I likely need to convert the carriage lead screw to a modern ACME or ball screw. So far I have not found a good solution to recreating the 3/4"-double start 2tpi LH ACME thread on the worn-out leadscrew nut. So replacement and converting all of the feed rates is looking more and more like the only economical solution. Thanks for going over the general details.

[@mattbentley8958]

Do you have a similar video for depth of cut, chip load and rpm for end mills?

[@dwightcarlson7136]

My old head is starting to ache. But nice video. Have to watch again when I have more time to concentrate.

[@haydentaylor66]

What lathe do you use? Great videos

[@shazam6274]

The Machinery's Handbook is not directly applicable for machining with metal working equipment which weighs less than 1 bus or costs less than 10 buses. A guy I knew was a chef on an aircraft carrier. After his service, he was planning to use his personalized Navy cook books to open a restaurant. He did. And he failed before he opened. Most recipes were for 2000, the smallest for 200. Scaling to 1 or 10 simply did not yield food he could serve. You did a great job on this video, delving into the assumptions, details and the calculations.

[@Blondihacks]

I bet he could throw a hell of a huge dinner party, though.

[@Rustinox]

Great explanation. All i need to do now is buying a machinist handbook.

[@smallcnclathes]

Try a carbide insert for aluminium on brass and aluminium. The 20ø of rake really reduces the power needed to make a cut and the edges are ground so they are very sharp. They are so cheap that using them for steel is not unrealistic either. They work really well on free cutting steel, they don't last as long as they do on nonferrous materials but as I said they are really cheap.

[@johnapel2856]

Good explanation for a complicated subject. By the way, here in West Virginia we use squirrel tongues per itty-bit. Meow and thanks.

[@Thysddcf235]

Great video!! Can you suplement this showing how using cermented carbide inserts change the numbers?

[@nerd1000ify]

Basically Hss speed x2 or x3. Carbide likes to go crazy fast.

[@Blondihacks]

Yah, that’s it in a nutshell. Carbide wants 2-3x the speed and DOC.

[@SpookyFXdotCom]

what about plastic? Like HMD plastic (the often used by hobbyists), or PVC (one of the most used) ?

[@can5projects563]

good morning from OZ. You are my favorite youtube person what an awesome video. I love the fact that you take your time to explain things nice and clear big hugs for you. all I know about machining is from KZbin university and your channel is the best classroom .

[@Blondihacks]

Aww, thanks! I appreciate that! 😁🇦🇺

[@dalemcinnes1834]

Hi Quinn, what i would like is a video showing how to know when turning or even facing if your rpm's are to slow or to fast. How to know when your tool is happy or not. Even with all the figuring whether you are on track or not. Even milling whether speed up, slow down or it's cutting good. Even whether to change the depth of cut or it is fine. I would sure like to learn about that and could you consider doing a video on that. Thanks. Dale in Canada

[@Blondihacks]

Hi Dale! That’s really about feel and experience with your machine. What I recommend is starting with light cuts (10 thou) and low feeds (0.005 per revolution). Then work up slowly from there and notice how the machine sounds, how the cut looks, etc. You’ll learn where the upper limits are.

[@clydedecker765]

I'd go for the King George's thumbs per fortnight if I had to do all that math too ...My answers would be about as accurate. (Ooo. Is that before or after gnawing on that leg bone of lamb? Thumb accuracy does count the amount of grease on the thumbs, right?) You have convinced me that I'm too old to change professions from retired Analyst to hobbyist machinist. Head hurts now. Thanks Quinn.

[@makosharkcnc7730]

Good video. Say like to ask you how did you get so many subs on KZbin. You have any helpful tips?

[@ron.owensby]

OK, now take a breath. Thanks for the video.

[@lukasvercaempst44]

I recently bought my first lathe. It's a 1930s leblond 10" lathe and haven't had the finish results I expected. The max rpm of the lathe according to the chart is only 550 rpm wich seems way to less in comparison with the speeds mentioned in the video. I initially tought the bad finish was due to my vidia cutting tools because I later found out these have high cuttingspeeds. Since my lathe is so old I higly doubt vidia or tungsten was already used back then so I now switched to HSS and according to the the video finish passes for 1" is around 800rpm but my lathe doesn't even come near. Does someone know why the max rpm is only 550? I really don't understand how they turned proper parts...

[@MetaphoricTechnique]

I have the same machine as Blondi! I'm just getting started out and I am having trouble figuring out what change gear setup is best for steel machining. I had to change them for a single point threading operation and now I can't seem to get my feeds and speeds right for turning/facing.

[@MetaphoricTechnique]

Whoops, I just finished the video and I think I have figured out now lol.

[@DavidRamirez0897]

How did you measure the tool nose radius with calipers? I would've loved to see that part. I cant figure out how to do it myself.

[@edbailen9068]

MH assumes you know what material you are cutting. I have no idea what any of the material in my scrap bins are. On the mill, I go by ear to determine whether or not I'm pushing the Grizzly knee mill too hard. On the Atlas 618, the belt starts slipping if I'm pushing too hard. I have trouble remembering that carbide tooling likes high speeds.

[@lisag2771]

Quinn, I want a mini lathe really bad. Would you recommend the Harbor Freight. I don’t want to have to tear it down right out the box like some people suggest.

[@Blondihacks]

Good question- I haven’t used the HF one myself, but my guess is it probably isn’t great. For a Mini-Lathe, take a looks at Sherline. They make nice stuff. For a bit larger, the Sieg stuff is pretty decent.

[@lisag2771]

Blondihacks Thanks. I will check them out.

[@markengineeringSA]

Speeds and feeds ,🙄 come on you wind it till the machine stalls, then take it down by one King George's thumb /fortnight 😂. just kidding another great video Quinn.👍

[@kajbyman3006]

I have a hobby lathe and a hobby mill,i am new to machining..Have had these for a year now,and destroyed a lot of mill bits and carbide inserts.Reason is propably wrong speed. The calculation here is hard to understand,not familiar with inches.Can anyone explain,if i have a 10mm mill bit and cutting steel what is the right speed?