Single Point Thread Chasing on a Manual Lathe

I had a small threading ob come up where the customer wanted two new shoulder bolts to match the shoulder length of an original part which requiring machining the threads further back. I show you my techniques on how to line up on an existing thread and progressively cut them to match the original. I understand that after filming this video some of this may be hard to understand or even see in the video so I would like to revisit this subject and film it again in more detail.
#abom79 #singlepointthreading #manualmachining #machining
Paypal Channel Donation: www.paypal.com/cgi-bin/webscr...
Support though Patreon: / abom79
My Amazon store where I'm adding many of the tools and products I use in my own shop. Amazon.com/shop/abom79
Visit my second KZbin channel where you can follow our travels, camping, RVing, cooking, and bbq!

[@joepie221]

Greetings Adam. Congratulations on the new shop and expansion of your machining capability. You should be very proud. Now for the hard part. Your setup was destined to ruin the original threads from the start. Locating the threading tool on the right side of a 60 degree thread with the compound set at 29 1/2, doesn't work the same for chasing as it does for cutting a thread from scratch. To simplify, imagine 2 cars on the freeway side by side, but the one on the right (original thread profile) is slightly ahead of the one on the left. Now the car on the right turns 30 degrees to the left while you only turn 29.5 degrees to the left. A collision will occur. Exactly the same thing happen to the original threads on this rework. I don't have the parts to inspect, but I'd bet ya dinner, the original thread PD is now smaller than additional threads you just cut. Align the 'V' first as deep as you can then back out the tool and creep back to that position. I hope you accept this in the good faith it was offered. Stay well.

[@quadrannilator]

I was wondering the same thing... not knowing how the original thread was made (process, geometry, tool wear, machine integrity, etc etc), one would be forced to first align the re-work tool to the thread as closely as possible before setting up a hard rule like the 29.5° compound setting - otherwise one is pretty much destined to cut over the original thread somehow somewhere...

[@danneumann3274]

I havent done it a lot, but when I do I put the compound parallel to the work engage threading and stop the spindle when in front of the threads then just dial the compound until the thread lines up. Ok so I am feeding straight in, Its a repair job.

[@verteup]

look like the nut threaded on great to me.

[@FinnoUgricMachining]

Actually .... this works just fine. The right flank of the cutting tool is aligned parallel with the right side of the thread "wall". When feeding is done with the top slide, the flank of the cutting tool keeps the distance from the right wall of the thread groove. This works because the top slide is in the correct angle which makes it parallel with the right wall of the thread groove. If Adam would have the habit of keeping the top slide parallel with the ways and would feed using the cross slide (like I do), this definitely would ruin the thread if aligned as shown. In this case the alignment is done perpendicularly to the middle of the thread groove.

[@FinnoUgricMachining]

@@danneumann3274 That's how I do it as well. I usually do not confuse myself with the 29 degree stuff. Actually I have my top slide dialled to be parallel with the ways. This makes it much easier to feed along Z-axis (along the ways).

[@VacFink]

The close up showing the tool tip riding in the previous thread was fantastic. Great explanation.

[@SixOFord]

Hobbyist lathe operator here, I've chased a thread on my lathe one time in the past, and this looks much easier than how I did it. Thanks for the education.

[@rickhand8228]

On my badly worn Sheldon lathe I engage the half nuts then push the saddle to the right (for right hand threads) when lining up the tool with existing threads. It must be a joy to use a tight, high quality machine like that! Another great video!

[@patrickirish9427]

I am a level 3 machinist apprentice and I have to say I've never seen a thread chased this way with a compound at 29°. Fresh threading yes 29°, but for chasing, I alway set my compound 90° aka so the ways of the compound are parralel with bed. Then I engage split nut, and feed back and forth with compound using a dial on compound to show when I hit either side of the thread wall. Then I split the difference, do an eye check and this ensures youre in the bottom. Then some guys like to take some pressure off one cutting edge of the tool which is fine and would be acheived by moving compound in direction of chuck maybe 0.002". Then use oil and gradually feed in using the cross slide over multiple passes until you gently clean it up.

[@thomasrebbeck6877]

Thanks for the video Adam

[@willjosephson]

Thanks in particular for showing what's important and what's less important. Knowing that is what comes with your years of experience, and what really helps the rest of us be better. Thanks as always.

[@timthetoolman223]

Exactly the kind of content I come here for. Thanks Adam!

[@ThomasLips]

It took me watching the setup two times to understand what you were doing with the cross feed and compound. I got it after the second run through. Thanks for sharing the information Adam!

[@mudgutsisgeordie]

Those camera angles were perfect. Seeing that back edge just clear the existing thread and start to cut the new one was amazing. Your content never gets old!

[@rexmyers991]

Your camera angle REALLY helped me to see what needs to be done to make it all work. Thanks

[@imbok]

It's always good to see a 'Hey Man' job turn into a learning opportunity. Thanks for sharing.

[@bigdatapimp]

how can anyone think that videos of cutting soap and other BS is satisfying, when there are videos like this that exist? This is a billion times more satisfying to watch.

[@paulcopeland9035]

Well, if you had a lot of soap and it was your job to make it fit somewhere, then cutting it might be interesting!

[@jmcexx]

Thanks, great video. I really appreciate the up close video during the cut. Also the shot when you're making the second bolt and we get to see how you're manipulating all the controls is really impressive and helpful to really understand what's going on.

[@tomkennedy5956]

I'm glad you have a new shop but I just enjoy the videos of you working from home better but I wish you all the best in the new shop

[@howardtoob]

The close ups are really helpful. Your explanation of how to pick up the existing thread is the best I've ever seen.

[@waynespyker5731]

With my eyesight on a thread of this diameter I would have used blueing on the rolled portion to confirm final alignment. Shallower threads would make viewing difficult.

[@matspatpc]

Nice. I had to do something similar - I thought I'd cut a deep enough M18 x 1.5 thread on a custom bolt I was making, and found that it wasn't quite far enough - so I had to pick it up again, and do another few passes on it. I just made it up as I went along, nut cam up with more or less the same method - using the compund-slide to adjust the position sideways and cross slide for depth. It worked! ;)

[@phrozenwun]

Really enjoyed to display of skill and technical know how! Thank you for sharing your knowledge of such an involved process - keep up the good work!

[@KimbrellBrad]

Critical technique there Adam. I've done it and destroyed my workpiece and done it with perfection (likely by accident LOL). Great video and glad to see you are back home.

[@DownToNerd]

That PM lathe looks so smooth to operate. You probably heard it before but congrats on the new shop Adam! Thinking back to the first few videos and seeing what the new shop looks like now. The progress made is amazing! Thank you for your content. (edit spelling)

[@tonyn3123]

Good camera angle, especially on the first bolt. Enjoyed. Thanks.

[@mdvener]

Really nice job. I could watch you n your work all day. Thanks

[@acurarl9929]

Great wrk. Always a pleasure watching you do your thing

[@bigbloodaxe]

Spot on as always Adam

[@mustafatoruk1791]

The lathe looks amazing

[@nolanchristiansen4040]

Close up shot is fantastic

[@richardkan8499]

Superb filming - so great to see the cutting process

[@howardosborne8647]

Top job,Adam. One additional little tip I use is to blue the original thread with Dykem and it makes it easier to see where the tool is initially making cutting contact with the thread flanks....it does help getting the alignment spot on.

[@nicholasgreening9946]

Fascinating and very informative Adam Thank you.

[@1903A3shooter]

For a gear head lathe that one is sure quiet. QUALITY.

[@darkmann12]

That golden-coloured knob on the toolpost looks very nice!

[@thegadgetcorner]

Thanks, this helped a bunch with an assignment in my machining class

[@kimjohnson4304]

Thanks Adam, I have a project coming up similar to this and have been thinking of how I was going to do it. Your timing making this vidio is perfect for me! Thanks

[@sanches2]

Thanks man! Liked this one a lot!

[@robertconklin3322]

Particularly good one Adam, thank you

[@jdmccorful]

Thankyou for the education.

[@isbcornbinder]

Thank You. Always the best.

[@ukp42]

I know cutting threads every day, normal for you, but it's still magical to watch the threads being cut. Especially when they match up, with existing threads, on the right hand side. Great video Love from Scotland 5* 😁

[@crazybrains777]

Thank you for these videos I am learning a lot.

[@llapmsp]

Great video Adam, thanks for sharing.

[@dirkkelly9596]

Thanks very useful and good camera angles

[@listprop]

Great detail. Thank you.

[@werkspartsllc7856]

Outstanding video! Really good camera work on this one. Gives me confidence when doing my own work when I learn how from you!

[@rodneywroten2994]

THANKS FOR SHARING

[@bombardier3qtrlbpsi]

Great job as always 👍

[@christophercastor6666]

Super helpful! Thank you as always! -CY Castor

[@RobertKohut]

Great video, and perspectives... 🙂

[@robr6369]

Great job thanks for teaching!

[@plainnpretty]

Interesting camera angles thanks for sharing

[@jacobframe8769]

Great video and work!

[@steveb9270]

Hi there and greetings from down under, I work for a valve manufacturer and cut threads on a daily basis have done for 30 years, there is no need to turn the top slide around to halve the thread angle. Keep it set to 0 and engage the halve nuts then simply adjust the top slide unit the tool lines up with the existing thread happy days, I hope this comment might speed things up a bit for you. Cheers

[@jamesbrussels5776]

Thank you Sir for sherring your expertise

[@silasmarner7586]

is sherring when you drink Sherry and offer the man across from you a swig?

[@buulb]

I'm looking forward to see more video like this even i don't have lathe now once you showed me i really would like to buy one and start to do my little DIY work

[@francisschweitzer8431]

That Precision Mathew Lathe is sooo quiet

[@floridaflywheelersantiquee7578]

Good job thanks for sharing

[@ron827]

Excellent tutorial and remember to remove all backlash if using an old worn lathe.

[@angelramos-2005]

Very interesting video.Thank you.

[@Nebulorum]

Kind of magical seem the transition between the factory and new thread…

[@onehot57]

I bet Joe really likes having you so close now!

[@jonminer9891]

Hey Adam. I think you changed from advancing at the angle to advancing on the vertical. That is why you started to cut the original threads.

[@__austrianoldboy_9861]

Thank you for sharing!

[@Smallathe]

Very cool. Not sure I got the hang of it... but it's a wonderful demonstration of skill! :)

[@scrotiemcboogerballs1981]

Thanks for sharing

[@peterspencer6442]

Nice work, you really clearly showed how the compound advances along the thread profile and it helped my understanding a lot!

[@dalton_5233]

Thanks for making the video! I've is been wondering for awhile how to find a new thread.

[@DavePB420]

Really interesting video Adam. As interesting as the main subject is here, it's actually helped me visualise the effect of using the cross slide as you feed it in, it really helps you see how it appears on a fully formed thread. Must admit, I still haven't mastered the cross slide on single point cutting, don't know why it puzzles me so much.

[@douglasbattjes3991]

I can't seem to locate the correct threading bar and bit for the Walter tool you used on their site, Great video , thanks so much👍👍

[@tonymackey370]

Great Video

[@realflight01]

Nice work Adam!! Ive always wanted to know how to chase a thread.. Cheers

[@gusm5128]

Internet engineers out in force in this one .

[@stefandr5252]

Indeed, 'I watched 10 videos about thread cutting and now I know better than a professional machinist'

[@patrickirish9427]

In peoples defence I'm a level 3 red seal machinist apprentice and the way he chased this thread here I don't believe to be the best way to do it. That's just me having worked with this stuff I'd say a little bit too with 50 other guys. Doesn't mean I'm right but this is a trade and anyone who has certifications to back it up should be allowed to criticise. Any normal machinist is used to constant scrutiny.

[@arfonjones7188]

@@patrickirish9427 'Any normal machinist is used to constant scrutiny'; what a refreshing counter to the tiresome 'armchair experts' nonsense. I applaud you young sir.

[@edwardralphsmithbezuidenho492]

cool video!

[@PhilG999]

Interesting! Never seen that done before. Without knowing anything about the application, I won't comment on the rolled vs cut thread question. Bolt torque, etc. Don't know if it has to be exact because using a castle nut means you may have to go a little tighter to get the pin hole lined up (never back one off to do that). Mechanical Engineer (now retired) IRL BTW. 😁

[@ronnydowdy7432]

Good job

[@tonythompson7448]

Not me Adam you do it how you want I'm watching good job as always

[@deakindog7525]

i have a chart that shows infeed at 30 or straight for all thread pitches. so far it has not failed me. for normal threads i have not needed to test fit

[@JayDee28]

that old bolt sure took a beating

[@kimber1958]

great lession, i just had to do the same on my p & w clutch rod, i think i got luckey !!!!

[@JohnSmith-lm1no]

This is an excellent video. I finally understand the use of the compound for thread cutting. Beautiful!

[@erneststorch9844]

I needed (2) 5/16-18 socket head cap screws 2" long with the thread all the way back to the head . They don't come that way. I did just exactly as you did . The main advantage to using the compound is your cutting on the left side of tool only. When you use the cross side you cut on both sides of the tool. That creates twice as much surface cutting and is more likely to cause chatter in the thread . You must use another depth for the compound than the double depth marked on a thread gage. My machiest hand book has the correct depth setting for the compound.

[@jondoes7836]

Worked at a shop years ago where we frequently had to pickup & chase existing threads on cylinder rod ends, SKF nut threads on shafts and rolls because of damage. Was always my job because I was the young apprentice.

[@jeffanderson4979]

Nicely done. Best thread chasing video on the net

[@Shop-Tech]

Joe Pie did one on his channel a while back.

[@samrodian919]

Did any one notice when the thread was first being chased that there was light showing either side of the cutting tool? If you are going to go in at 29 and a half degrees to only cut on the left side of the tool then surely the right side has to be within a thou or less of the left side of the thread( to the left of the peak) otherwise if there is say 8 thou gap to the right side of the tool then the centre of the new thread being cut is 8 thou to the left all the time. Also as the tool got deeper did anyone notice that the original thread was being cut and chips were coming off. Which to my mind says my original statement was correct Adam was off too far to the left when he set the tool up to the original thread.

[@Rorschach1024]

He addressed that at aporox 17:30.

[@markgordon4368]

Thanks ☺️

[@drthik1]

Nicely done

[@markthomas5699]

Good to know better than making a new part

[@user-oj4xh8cg2l]

nice trick to know. I'm a bit puzzled by the tiny gap one could see on the close up views to the right side of the tools with the original thread : would that not mean that there is a slight misalignement of the tool with the existing thread (i.e. when one is plunging at 29°1/2 without touching to the right, when bottoming the right of the original thread will still remain a bit further away on the right side of the tool) - should not the tool be in light contact of the right thread trailing surface rather than a few thou away?

[@eliduttman315]

I believe we are seeing remnants of the original thread relief that was present on the provided bolts.

[@rogerscottcathey]

I saw that too, and it definitely started shaving the original threads. In the end one thread looked flattened

[@1903A3shooter]

He is feeding the tool in on an angle, but the tool is set so the thread form is correct, tool is at 90 to the work piece.

[@ryanlukens9280]

What you are seeing is the original thread was actually tapered at the shoulder end. Watch closely around the 12:15 mark and you can see both this taper and the cutting tool slipping almost exactly in between the original threads.

[@user-oj4xh8cg2l]

@@ryanlukens9280 which is my point: should not the tool be just touching or almost the right side, since it's going to be fed in at 29.5° , hence along the right side of the thread?

[@chrisarmstrong8198]

Alternatively, turn the chuck by hand (with the half-nuts engaged) far enough to remove backlash in the gear train. Then, with the work stationary, line up the RH flank of the tool with the RH flank of the existing thread. Rotate the chuck by hand a little and tweak the cross-slide and top-slide settings if necessary.

[@chrisarmstrong8198]

@@bigboreracing356 Maybe OK, but not guaranteed to remove the backlash since it depends on which part of the lathe stops the fastest (i.e. spindle or gears in gear train).

[@belatoth3763]

There is always a backlash. It would be simplier to turn the compound square, engage the feed, dive it by hand until the carriage moves, then find the bottom of the thread by playing with the compuond X and cross slide Y. Small threads can be cut by feeding Y square.

[@conejoyconejamillan3340]

Thank you for sharing!!👍🏽👍🏽👍🏽👍🏽👍🏽👍🏽👍🏽

[@MAC_6.7]

Good content

[@leontierralta]

Hola buen día saludos desde Riosucio caldas Colombia

[@Joe___R]

Why did the threads at the transition from old to new break? If you were matching the existing threads why did you cut them as well while cutting the new ones?

[@Sun-ut9gr]

They didn't break, he was machining through the original relief

[@Steelcrafted]

It's funny even though I KNOW I can engage the half nut on every other number of the thread dial, I still only go on the same number every time, just to be safe lol 😆😆

[@CatNolara]

I would propably just have prepared that thread similar to how you did, but then cut it with a die. Should work pretty well since the existing thread gives you a nice start. But doing it this way gives you a way nicer thread, so thumbs up.

[@3-body-problem]

How can your eye even see that small detail? I'd need three magnifying glasses to even see the tool tip let alone making chase a thread. The closeup footage helped explain this really well.

[@jemijona]

What you need is a GoPro hooked up to a 75" TV so that you can see the detail. 🙂

[@noeldickerson2798]

Adam any tips for making my compound more ridged ??

[@user-gm4pi9bd2x]

Здравствуйте. Не понял почему съело один виток резьбы между первоначальной и последующей? Там был выход резца? По видео не видно.

[@demonknight7965]

I noticed that too. Where it transitioned from the original threads to the new. There was a flat thread.

[@firesurfer]

Я думаю, что это было старое облегчение от предыдущей темы. Когда новые нитки были обрезаны, от старых нитей не осталось достаточно мяса, и на одной нити осталось плоское пятно. I think that was old relief from the previous thread. When the new threads were cut there was not enough meat left over from the old threads, leaving a flat spot on one thread.

[@stevenhavener7327]

I have picked up a thread 3 times, almost back to back on customers parts, I was terrified, still am... but it can be done !

[@skipgoryews1356]

Hello you mentioned the nut may have a burr on it. it is so close but just not there. I mite try running a tap in the nuts just to make sure . Thanks for the vids .

[@bobwatkins1271]

12:18 It looks like the cutter is slightly ahead of the existing thread during these initial cuts. Does the 29.5 degree compound angle compensate for this by the time the thread is finished?

[@silasmarner7586]

Yes!

[@markkuaaltonen9153]

That Walter tool must be good quality, it hurted my eye watching how deep cut you made few times.