Single point threading on mini lathe

[redvan22]

I recall from shop class that you use the compound slide to advance the tool cut depth and the cross slide to pull away from the work at the end of the cut to reposition and move back in to the proper position before advancing the compound and then wait for the the appropriate number to come back around on the dial.

I believe my two major mistakes were:
1 - In shop class we didn't have Chinese lathes so they way I did it would have been correct in some ways if I was back there in shop class.
2 - Wrong end of the two ended tool bit was in use.

I'm definitely going to setup again and practice with the straight in method.

Thank you all for the quick responses and suggestions.
Michael.

 

[redvan22]

Awesome!
Set my Chinese compound to 60 degrees and used the correct end of the tool bit, ran another piece and what a beautiful thread I got now.

Looked into the straight-in approach because it seemed to me that both sides would be cutting and that could mean chatter and as I suspected, it was advised against if using a less rigid lathe (like my mini lathe) so I tried the 60 degree setup instead.

Thank again everyone.
Michael.

 

[DavidR8]

Glad you got it sorted out.
You would not be the first person to have gotten the angle wrong.

 

[WobblyHand]

Awesome!
Set my Chinese compound to 60 degrees and used the correct end of the tool bit, ran another piece and what a beautiful thread I got now.

Looked into the straight-in approach because it seemed to me that both sides would be cutting and that could mean chatter and as I suspected, it was advised against if using a less rigid lathe (like my mini lathe) so I tried the 60 degree setup instead.

Thank again everyone.
Michael.

Pictures of success are needed! (Pictures - or it didn't happen!) Show us the new thread you cut, it gives all our new machinists something to strive for.

When I was starting out, I had the angle wrong too. And I had some dreadful looking ragged threads as well. Thanks to help from HM and kind members, I was able to learn the right way to do it. Glad we could collectively help you pick up a new skill.

 

[redvan22]

Pictures of success are needed! (Pictures - or it didn't happen!) Show us the new thread you cut, it gives all our new machinists something to strive for.

When I was starting out, I had the angle wrong too. And I had some dreadful looking ragged threads as well. Thanks to help from HM and kind members, I was able to learn the right way to do it. Glad we could collectively help you pick up a new skill.

Little rough, can't find my scotch bright but much better results. Also didn't turn an entirely new piece, simply used a piece of scrap to test.

 

[savarin]

one thing I do if the threads are rough like on some mild steels is use a counter rotating wire wheel in an electric drill to burnish the threads.
Do it in both directions, you will be surprised at how it improves the look. Doesnt seem to reduce the thread strength either

 

[GeneT45]

Another trick is to make a couple "spring passes" as you finish up - those are second passes with no further infeed - cleans up some of the deflected material. I like Cratex sticks for a final polish (just the dark green / course).

GsT

 

[ericc]

Good thing you sent that picture immediately.

 

[koenbro]

What is the cutting depth per pass that you guys recommend for a thread?


Sent from my iPhone using Tapatalk Pro

 

[SouthernChap]

Good thing you sent that picture immediately.