Bob,
I have a Sherline lathe and do threading / turning on it. It was a giift, has the x axis extended table, steppers
are around 125 in/oz, microscope attached to it, uses a single index for the pulse to do threading, motor is the newer more powerfull version, and use ean MPG with it. I use it for making small model parts as it fits the need. If you look at what I made thread you can find some postings from me.
I plan on doing some modifications to it. Just struggling with what i really want to do to it, make my owne lathe,
or modify a mint 6" Atlas i rebuilt and that is laying around, finish a add on attachment for the larger lathe for doing fine work ( basicaly a put in place, very accurate ball screwed x / z ).Too manny options, maybe i will do them all.
The "punny" lathe, no knocks on Sherline, but it could easily take a ride on Hood's lathe carriage.
Just want to keep things in perspective.
Since your interested in turning, you may want to start following the LazyTurn ( currently being developed ) thread and take a peek at LazyCam Turn ( Lazyturn will replace it ). There are manuals in the Members Doc's about both which could be of value to you. I am not going to update / or enhance the LazyCam Turn manual and the LazyTurn manual is constantly being updated to reflect some 250 plus pages of posted text. Feel free to comment as i am open to constructive comments.There is the Mach III Turn manual but there is no Sherline specific manual.
As far as threading, there are numerous posts about it but nothing captures it concisely for a punny lathe.
Now on to your questions:
Yes you can do threading with it and we have done down to 1/80's. The threading really works well for the
punny lathe users as Art made provision to address issues associated with punny lathes in Mach.
Sorry but it's my lathe and i can call it anything i want! A major problem that someone will have with threading
is accuracy. It dosn't take much to screw up a thread.
I would recomend larger steppers. Tools should be razor sharp and cuts need to be very small / and plenty of passes.
Spindle speed, steppers used, accuracy of the lathe all act as a system. Each can affect how you need to run
the punny lathe for threading and will define what the outcome is. You can use the PP with backlash compensation,
the SS ( backlash is coming ) and modify the threading wizard for g32 output instead of g76.
I got to go and will post more later. You can write a book on all of the above. I get a chance I'll put something together on this if time allows. Feel free to ask questions.
RICH
MODIFIED: mACH VERSION 3.042.12 AND ABOVE IS FINE ( if memory serves me) , LOCKDOWN X.*********.20 IS GOOD FOR THREADING.
HAND CRANKING A LATHE HAS IT'S PLACE BUT CNC IS SO MUCH BETTER. NO YOU CAN'T SLAVE THE Z AND MECHANICALY HAND CRANK IT LIKE IN DESK CNC. NO I DON'T WANT TO COMPARE APPLES AND ORANGES.