Threading on a Lathe - Just the BASICS
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- Опубліковано 23 сер 2024
- This is a viewer requested video that covers basic threading. It uses the "feeding with the compound" method. This is the method use in most South Bend, Logan, Atlas, etc. instructional manuals and in my opinion, yields the best results on smaller lathes.
PLEASE NOTE: My comment about total thread depth and reading it on the compound was way off. I pinned a comment to the top that explains this math.
20:50 actually if you need to go Z deep then the compound should be ~ Z x 1.15 so if your cross slide would have to go .050 then the same depth on the compound @ 29° would be .050 x 1.15 = .057, that is for TOOL travel for both cross slide and compound not diameters.
In this case if your minor diameter is .417 and the stock is .500 then .500-417=.083 so the cross slide must move .083/2=.0415
So the compound needs to move .0415 x 1.15 = ~.0477
If this is true (which I'm sure it is) I should have left my comment out of the video. I'm glad I made the text comment. Thanks for the info.
@@WinkysWorkshop There is another way too. Your clearance groove is roughly at the minor diameter and on your last cuts, you can see the tool just nicking that diameter so you know you are near the bottom. So if you make your clearance groove correctly it can be used as an approximate gauge too.
Another option is to precisely use the cross slide to cut the .417” minor diameter. While at the minor diameter set the compound and the cross slide to zero. Back out the compound to clear the work. Now without calculations you can start cutting the thread by advancing the compound to the zero mark.
@@billshiff2060 Excellent idea! Thanks. Also I pinned your other comment to the top. Good information.
@@davidlloyd6045 Cool. That works, but only if you cut the relief groove with the threading tool you are going to use. Of course You could always cut the relief with the square tool then touch off on the surface once the threading tool in in place and zero it then. You could also cut the back side chamfer with the threading too at the same time.
A good effort in explaining the basics for beginners. I'm sure you'll get a lot of "experts" telling you what you should have said, but until you know how, you don't know, so this is where videos like this help us learn. We all started from a position of ignorance after all!
So true
i don't see any of the Monday mornings quarterbacks doing any effort to show us beginners ! so they , in my opinion, can go pound sand
this video is obviously years before the fast retracting threading tool that you made and the half thread cutting tool. that little innovation still tickles me ! it proved for me that the threads are definitely cut only on one side of the threading tool.... which is no big revolation to most guys out there that have done any single point threading....but it does show the importance of putting the compound on 29.5 deg ! the ROUTINE here is the important thing to newcomers I think. the backing out of the cross slide and then returning it to ZERO every time and then advancing the compound the amount you want to cut....and the all important half nut..... I would like to add "what happens if you miss the line on your thread dial ?" well
what happens is your cutter is no longer in sync with the threads so the cut is that much out and usually cuts the existing threads in half and you have to start all over ! so that half nut is CRITICAL and on some lathes their sticky and don't like to disengage or don't want to catch on the threads you enguaged it on ...( it will slip back one thread and you will be out of sync) a half nut being sticky really SUCKS because you'll crash the cutter into the chuck bust cutting tools break gears and all kinds of nasty stuff can happen. a slipping half nut can be bad as well but usually only destroys the part you are threading..... if you miss dropping the engage in the thread dial spot IMMEDIATELY disengage the half nut chances are good that you can stop the cutter before it ever enguages the part. and simply try it again.... that is why I usually pull my cross slide back away from the part about 6" just incase I miss the half nut mark ! threading slower makes missing it far less likely !
however I am sold on threading away from the chuck no crashes possible that way.
I could have gone into a lot more depth but wanted to keep it simple. Yeah, a messed up half nut is scary.... been there!
sounds to me like you have a clausing !! i have one and it does what you described lol
@@danhoag373 no it's actually a Logan 911 as old as I am to the same month !!! I think worn half nuts is the cause of that behavior that and slow reaction times ! LOL
@@WinkysWorkshop you did great Mark ! I always like your videos keep up the good work !
@@bobkelly2447 thanks
Thank You so much for producing this video and for the personal recognition. I have watched literally scores of videos on making threads but they always fixate on the cutting aspect and nothing on the setup process. As You see from the comments, don't be surprised if this video goes viral since it's the best instructional video out there. I had envisioned the need to set the compound at zero to begin each cut, but I have never seen a video that identified the thread meter or how it works (long mark / short mark). You have helped me in two areas. 1st on the machine setup and the procedure for cutting threads (well explained) and 2nd ... on what type of lathe I want. I am enamored with the older equipment and now it's all I will consider for purchase. I want to thank You very much again for producing this video for all of us.
I'm glad you like the video. I left off one thing. If you get a lathe with change gears its a good idea to do what they call a scratch pass. This is making the first pass just scratching the surface. This is so that you can check with a thread gauge to make sure you have the correct thread per inch. With the quick change gear box it's probably not needed. I agree, I love the old machines. Buying and restoring a machine also gives you a very good idea as to how everything works. Be aware that the old machines will likely have significant wear. My South Bend is worn badly but I manage to work around it. Machinists tend to be obsessive about accuracy but quite often is doesn't matter plus you can do accurate work with a worn machine, it just requires a bit more work. As a hobbyist this extra effort is insignificant. If you get an old machine look for Broken gears. Gears are hard to make and expensive and sometimes very hard to find. Look at bearing ware. Most plain bearing lathes (like my south bend) have a bearing cap that can be removed... its a good idea to take them off and make sure they are not destroyed... a little scoring is normal. If the lathe has ball bearings, they can be replace but they usually cost about $250+ . Last, I recommend paying the extra for a lathe with a quick change gear box. Change gears are a pain.
@@WinkysWorkshop very well put!!!
@@WinkysWorkshop Thank You again. I've learned to guard against my fervor on purchases like this. My best results have been to engage a "mentor" (like You) to guide me. Our family has a gunsmith that is now a friend as well. He has a lot of lathe/mill experience and I've asked him to help us with the buy. We've found a lot of equipment on Facebook Marketplace but like You say, a lot of junk along with a few good machines that they incidentally want a fortune for. Patience seems to be the hallmark of getting a good machine for a reasonable price. Hopefully we will luck out and chips will be flying in our shop. Thank You so much again.
@@danhoag373 Thanks
@@richardgreen7811 Yes, Patience and Persistence. The good deals only last a few hours.
Thanks, I thought that I knew how to cut threads, but this was a useful refressher and I'll refer back to it.
The man who set up my first lathe fitted it with a VFD. He showed me a slightly different technique which doesn't use the threading dial. Essentially, at the end of the pass, you stop; back out the tool; run the motor in reverse; go back in and advance; run the motor forward. It's the same thing, but without disengaging and re-engaging the half nuts. It works well until your old lathe decides to spontaneously disengage the half-nuts, and then you have an issue....
Reversing works well but some lathes don't stop fast enough. Also, if you have a inch based lathe and install transposing gears to cut metric then you have to use the stop and reverse method. Thanks for watching.
This was a very helpful video for us novius operators. Very helpful.
Thanks for sharing.
Good to hear, thanks
Nice job. The collet chuck is really for accuracy, certain work holding and clearance, maybe rigidity on a screw thread spindle. Mines a D1-4 cam lock so there’s a lot of rigidity there. But I am getting a collet chuck eventually. I can tell you for sure, you definitely need to use the compound with those cheap import thread inserts. I’ve broken many using the cross slide. In reality, unless it’s a big thread the cross slide is all you need. I order higher quality inserts and that negates the need to use the compound. Cheers. Edit: I mainly single point metric. Rarely imperial. Just use a die for them. Quicker.
Yes I use a die for anything smaller than 1/2". Yes a threaded spindle (especially the smaller diameter spindles) is a weak point. The original chucks for these smaller lathes were very low profile but all the new chucks are at ,least 2-inches deeper. Usable? yes but collet chuck has the same stick out as the original chucks... MUCH more solid.
Something I do not understand is this idea that feeding with the compound is more difficult or more complex... or even undesirable. Even your statement, "negates the need to use the compound", implies that if you don't "need" to then feeding with the cross slide is better or that the compound is more difficult. Given a choice between the two I much prefer the compound because it's easier. You do not have to remember the dial setting when you go back for the next pass. You simply put the cross slide at zero every time and advance between .020 and .002 with the compound each time. The only reason I can think of that straight in might be preferred is to be able to direct read the depth of cut.
This is a very good review for myself, as I only cut threads about every 6 months or so. As I watched, I found myself thinking " oh yeah, I would have missed that important detail " !!!
Glad it was helpful! thanks
Great threading tutorial there Winky. Thanks for the video keep on keeping on.
Thanks Harold!
Pretty basic, but I always enjoy a well made single pointed thread. Enjoyed and thanks Mark, cheers!
Thanks, I agree, I enjoy the process.
Thank you, thank you, thank you, I might go downstairs and give it a try now. Now that I understand it a lot more.
Cool!
first one or two doesnt need to be perfect!!!
Another good video on threading Mark. I'm currently making an ornamental turning device for my wood lathe and I have to cut an 8TPI thread for the chuck. I'm going to briefly discuss the angles, but since my video is not on threading I don't what to take up much time explaining this stuff. I will link your two videos with some others on threading so that my viewer can get more info on the subject if they want it.
Sounds great! thanks. The device for your lathe sounds like fun.
Hello Winky, another good video, very informative, thanks for sharing. Cheers from me, 😃👍👍👍👍👍
Glad you enjoyed it
Good demo on threading,Mark.Thank you.
You are welcome!
Thanks Mark. Great and easy to understand explanation.
You're welcome!
Great explaining tutorial Winky.
Thank you! 🤗
Good one, Mark. Very well explaned.
And next week, metric :)
Good idea... although I have no transposing gears and no brake on my lathe. I have cut metric several times but but they were actually the inch equivalent. It works if you go a little deep and the threads are short. o:)
Excellent information winky, thanks for sharing..
You're welcome, thanks for watching!
Learned a lot!
Thats great!
Thanks
Your Welcome
Thanks very helpful.
you're welcome
Hi winky, I really enjoy yiur videos. I own a logan 211 lathe. I am needing some new gears as I managed to crash my lathe. Where is it you are buying yiur nylon gears from? Thanks Scott from New Zealand 🇳🇿
Sorry to hear about the crash. I bought them on ebay but the seller also has a web site. The gears work well but tend to hang on to metal chips. On the plus side they are cheap and also act as a safety gear. I had a crash and it took the teeth off the gear. Hopefully he ships to NZ. If I was you I'd buy a spare. printerdoctor.com/
Thanks for your recommendation regarding new gears. I habe just ordered a couple, also some 16 tooth gears for a quick change gearbox on another logan lathe I have in pieces for a future project, unknown model . One of many projects lol.
15:45 One thing guys fight with is how much to take per pass as you go deeper. To cut out an equal VOLUME of metal with each pass
First you pick your first cut depth which is typically 20-50% of the total projected depth (this works for either the compound or the cross slide) then you reduce each following pass by the square root of the pass number.
So for a projected depth of .048 and if starting with a first pass of .020:
The 2nd pass would be .020 x sqrt2=.0282 or .0083 deeper.
The 3rd pass it would be .020 x sqrt3=.0346 or another .0064.
The 4th pass it would be .020 x sqrt4=.040 or another .0054 deeper
The 5th pass it would be .020 x sqrt5=.0447 or another .0047 deeper
and the 6th pass(s) with .0033 remaining would be to bring it to final size
and so on till it's done.
In this case it could be done in about 6-8 passes.
I always just wing it and go by feel. Lots of ways to do it but that works pretty well for me.
I'm with ellieprice, I just wing it.
@@WinkysWorkshop I get that. Winging it is a luxury only diy home gamers have but it causes troubles when it's for profit and for a customer. Then it will have to be done efficiently and be in spec so it passes QC and still makes a profit.
I notice Winky that you do not take any spring passes, If the nut is still tight after deburring the thread I do a couple of spring passes without adding any more to the compound. With regards to a previous video where you showed how the trailing edge of the thread was a saw tooth effect from the compound avances here is what I was taught to do over 50 Years ago. As the nut is still a bit tight, advance the CROSS SLIDE by a 1/2 to 1 thou and make another pass. That will then remove the saw steps and make the thread the full form of the threading tool. Regards from Australia.
Yeah a spring pass might have done the trick although its a judgment call and the threads ended up just about a perfect fit. For sure the cross slide advance would correct the finish.
I also made a video with a deliberate repeat in it.
Using a different method.
I'll take a look
Very informative for me, thanks
Your welcome!
I know it’s off subject but l have several questions about the replacement motor for your index 40-H. I need to replace mine and I am not finding a suitable replacement on the Vevor website any help would be greatly appreciated
This is the motor I used. The only issue I had was wiring the drum switch and that was just my own inability. An exercise in logic for sure. I got it but it took me a while. I now have a 3/4 HP 3 phase motor with a VFD on the mill. Sometimes you can find a good deal on used 3-ph motors and the variable speed sure is nice, This is the vfd I used: amzn.to/4bU3axg
@@WinkysWorkshop that’s what I thought since Vevor didn’t have any options in 3 phase that you went with a single phase motor and must have been dissatisfied. I have found several three phase options from different sources but they are all 5/8 motor shafts and the 2 stack drive pully on the index is 3/4 id and I am not able to find a replacement for a 5/8 inch shaft. Did you just use a single pulley and rely on the VFD for your variable spindle speed thank you so much for your help and advice
@@phillipmattingly7826 Here's my 3ph motor and VFD install video link. Something interesting about VFDs is that you can safely (as far as I know) double the rated speed of a motor. You lose a little torque but a lot more when you go slow. You can use a pulley combination that is fairly slow and still get higher speeds. My mill goes from 200 to 2100 RPM with a single motor pulley in the top position. My motor had a very short shaft. It's works great. The VFD I linked to in the first reply also converts 110V to 220v 3ph. ua-cam.com/video/_wla3UP5s0Q/v-deo.htmlsi=22ub_ibp7VsRpWh6
@@WinkysWorkshop thanks for your help and yes I have watched the video you posted and will do so again. I haven’t watched them all but I have watched a lot. I really enjoyed the series on the index restoration. I would love to converse directly with you but I don’t know how is there a way I can post pictures of my rebuild. You are doing a great job and keep up the great work you have been a tremendous help
@@phillipmattingly7826 You can contact me at Winkysworkshop@GMX.com
Which is better, the auto retractor or manual in your opinion? Great job as always 73 dan
The auto retract in most cases but it require a bit more setup. This video was a basic starting point.
@@WinkysWorkshop yes it was and a darn fine job of it to
i can really relate to the pucker factor lol
@@danhoag373 Thanks
Is there any difference to cutting metric threads? I primarily work on Subarus, and oftentimes need a very uncommon long bolt that is 8" long, usually something like M10 x 1.25. I have been looking at buying a lathe for months but have not pulled the trigger as I was unsure if the gear ranges for thread cutting interchange between imperial and metric. With your chart I saw some that said 3 1/4 TPI or 11 1/2 TPI etc.
Thank you for the very basic into video, I never understood how the compound and cross slide functioned differently, or the use of a thread dial gauge.
Glad you enjoyed the video. As for metric, the process is exactly the same. However, some lathes only do inch and some only metric. Many modern lathes will do both but they are usually more expensive and have two different lead screws. With that being said, you can get what they call, Transposing gears for an inch lathe but you have to leave the half nut engaged, stop the lathe and reverse for the next pass. This requires that the lathe has a brake as coasting can be a problem. I have cut several metric threads that are close to inch threads but this is not ideal. If the thread penetration is less that 3/8" it works well enough (like a nut),
@@WinkysWorkshop Colchester and I think Harrison lathes (and probably others) use a 127 tooth gear in the primary gear train to convert from imperial to metric, I believe it's not perfect but very close, close enough. I have cut metric threads that way with success. From Cumbria, UK.
@@seapy2398 Yes and I'm sure you have to reverse the lathe instead of using the thread dial
Nice tutorial............next time for fun do some left hand threads.
Yeah, this are actually easier because you thread away from the chuck.
Internal acme threads are fun using amco 45 brass 😂 left hand
Nice work sir. He he. Basics is still difficult.
It takes practice but its easier than you think.
Don't forget, Whitworth form threads have an included angle of 55°. So set the compound accordingly, say 27°.
It's always good to get back to basics 👍.
Good point although whitworth is very rare and I wanted to keep this basic.
Also ACME, buttress, BA and square.
When cutting 60 degree threads, the compound is advanced 1.149 times the thread depth shown on a thread depth chart. Example: With the chart showing .047" as the thread depth for 13 TPI. the compound is advanced .054" (.047" X 1.149 = .054")
Good information. Thanks
Nice. I don't have a thread dial on my lathe. Do you have a video on making yours?
Here's a video. They are very basic and you don't have to make it fancy. The trick is, knowing what gear to use. I made one but also knew the tooth count and diameter. There is no load on the gear so any gear with the same diameter and tooth count will likely work. ua-cam.com/video/-BIX0cJw5Ls/v-deo.htmlsi=ogVFlN7madvy36Io
@@WinkysWorkshop thank you
After making a cut and you return the carriage back to the start does it have to go in the exact same spot or does it just have to be close?
Good question. It can go anywhere past the end of the stock. You just have to wait for the correct make when you engaged the half nut.
Good explanation. I don't think you mentioned using back gear on lathes that need it to go slow. I was also taught to do a spring pass before testing.
Both important but I think I mentioned the back gear. I left off a scratch pass and spring pass.
Very good thanks you.
You;re welcome
Isn't it amazing how much there is to know as a machinist? I think machinists are underpaid.
I totally agree. My knowledge is basic, about 1% or less.
It's more about understanding than knowing, but indeed, it's a lot.
@@RustinoxUnderstanding plus experience makes a good machinist.
@@WinkysWorkshop No way! There’s always something to learn but your basic is 90 plus.
What happened to a scratch pass?
I probably should have included this for those that have change gears. With the quick change gear box it's hard to mess up. Thanks
Hi I've got exactly the same hardinge lathe as you, I can post pics of the turret and threading attachments, I also have a large set of collets and gears, also index plates,, if you need any pics let me know, I posted a video on my other channel , metal micky thanks
I looked for your channel and did not see it.