Rookie makes a Criterion type Boring Head adjustment screw. Lathe alignment and fine thread turning.

[@mikebarton3218]

Hi, could it be 50 tpi? That would make more sense. Also, have you considered that at the age of the item it could be a 55 degree thread rather than 60? Cheers.. Mike

[@EnoRestoration]

Good idea. I didn’t have a 50tpi gauge but will see if I can cut a test piece. Thank you for the idea.

[@EnoRestoration]

And no, don’t consider the angle, another good idea. Thank you Sir.

[@mikebarton3218]

Thanks for your replies. I certainly take my hat off to you for taking on this challenge. Isn’t KZbin amazing.. you upload a video and seven minutes later here in the UK an insomniac hobby machinist watches it and we have a dialogue! I must get back to the video as I have paused it 😂

[@EnoRestoration]

I'm glad I can contribute to your insomnia...! I appreciate your suggestions above, I think you are on to the right answer.

[@timothyosborne8285]

If it is like most boring heads, the dial will either have 20 or 25 divisions. Dials with 20 division have 50 threads per inch (50 times 20 = 1000 or 1.000 inches) and dials with 25 divisions have 40 threads per inch. (40 times 25 = 1000) Keep going, your working your way through it, and that's exactly how you figure it out.

[@EnoRestoration]

That makes the most sense, must be a 50. I'll try doing this again. I appreciate the feedback, thank you! Learn by doing.

[@ApacheRanch]

Well done

[@EnoRestoration]

Thanks!

[@Freetheworldnow]

Perseverence makes you a winner! 😅

[@EnoRestoration]

Thank you for watching!

[@axelknauff3928]

It might be a M8x0,5 metric tread as well. The pich would fit. The inner diameter should than be arround 7,5mm.

[@EnoRestoration]

I think you are right to think my thread pitch is incorrect. I do think its imperial simply due to its age, but if a 50 tpi thread doesn't work, I'll try anything else!

[@chrisstephens6673]

​@@EnoRestorationthe fact that the thread in the body has an insert could mean that someone in the past has, or was, trying to converted it to metric. One way to check small internal thread pitch is to turn a piece of close grain wood and just thread it into the hole. It won't damage the hole but will mark the wood which you can measure with thread pitch gauges.

[@EnoRestoration]

This is why I enjoy posting these videos, lots of great ideas from those with a lot more experience than I. You have a couple of astute points there, thank you!

[@fengelman]

seems to me that the "hard spot" might have been where the locking screw comes in?

[@EnoRestoration]

Thanks for the suggestion but I'm thinking now (based on a lot of feedback from my viewers) that I have the wrong thread pitch. It its indeed a 50TPI and I used a 48, then my screw could have gone in a bit before it started to wedge against the different pitch thread.

[@fengelman]

@@EnoRestoration yes, I’ve been reading the comments, and 50 tip makes a lot of sense

[@CothranMike]

@@EnoRestoration correct, wedge is the right term. Two Archimedes screws interior pitch 50 while the exterior of created screw part is 48. You'll be able to engage for at least three turns before the tightening requires lots more force and at that interface there is a bit of float before the torque required makes a 'no set screw required' fitup.

[@EnoRestoration]

Yes... that's it for sure. The best teacher is experience. And a helpful group of YT viewers. Thank you!

[@horacerumpole6912]

That was maddening to watch-JUST BUY A TAP!!!

[@EnoRestoration]

Yeah... but I'm stubborn... and if I did buy a 48tpi tap it still wouldn't of worked. I needed this group to tell me its a 50!

[@chrisstephens6673]

I think you are going the wrong way in trying to make the hole conform to your perception rather than changing newly cut thread to fit the hole. I suspect that thinking it 48tpi is not correct and as others have suggested it is perhaps metric. A 0.5mm would make sense but a 48tpi doesnt as graduations would be hard to work with. When adjusting your tailstock the two adjusting screws are there to move the body and not usually meant to hold it in place. Over tightening things just isnt a good plan, even cast iron acts like rubber on the micron scale of things, once used to move the body merely nipping them up should all that is needed, you are not trying to anchor the Titanic.😂 Edit PS, once you had forced the thread through it would have been a good opportunity to remeasure the pitch, almost certainly not 48.😢 At the that is how it is looking from several thousand miles away. 😅 With all the possible things that didnt go quite right, i forgot to add congrats on getting it fixed.👍

[@EnoRestoration]

Good tips on the tailstock. Getting that aligned properly has alluded me. I'll try your suggestions out. Clearly I was anchoring the Titanic! As always, thank you for the support.

[@FullSendPrecision]

Send it to me and I'll laser engrave the index marks for you.

[@EnoRestoration]

That would be great! Let me rethread it and I would like to take you up on that. My email is on my channel page if you would send me your contact info.

[@Airtight215]

Are you kidding? You don’t know what a threading insert or hss tool is? You aren’t cutting a thread without one.

[@EnoRestoration]

Not kidding, new to a lot of this stuff but learning everyday. Thanks for the support and for watching!

[@charlesmoody4304]

Frustrating it’s part of the trade

[@EnoRestoration]

Yes it is and I guess that's part of the reward. But I did learn something that I applied in my last project. I needed to be more careful about determining thread pitch. Thank you for watching and your comment!