Lathe Machining of Delrin

[btvarner]

Here is an image.

 

[btvarner]

that makes sense as a possibility. Maybe I need to try a much shorter piece. I am trying not to waist the material as each item I am making is only about 3/4" in length. A 12" lathe is small enough that 2" stock will not got through the chucks or spindle....

 

[btvarner]

Ok, I do not know what is happening, but by last several responses have just disappeared and not posted. Trying again.

Charles scozzari: That makes sense as a possibility…. I am just trying to save the material as the pieces I want to make are only about ¾” in length. That would mean a lot of waste.

 

[Charles scozzari]

Here is an image.

I have never had a problem machining Delrin, but I would not have used that insert. I have success using a SPG322

 

[rwm]

How do you know your steady rest is on center? It may be causing wobble and pulling the work out.

 

[btvarner]

Thanks rwm. The same way one always checks center. Dial indicator attached to the ways.

 

[btvarner]

I just thought of something. Look closely at the study rest. Its not backwards is it?????????

 

[rwm]

That won't work? It will always read zero runout with the stock touching the followers?
It's not backwards.
Edit: I have always called that a steady rest. The other type of rest is a follower. That bolts to the carriage.

 

[btvarner]

Yes, sorry I meant study rest. How would you ever chuck something that long and get it straight, without the followers touching the material? Seriously asking???
I should chuck it without the sturdy rest. Dial indicate it, turning slowly until centered. Tighten the chuck. Then what? Adjust the followers to just touch or just not touch the material after that? Not understanding....

 

[rwm]

Center your stock in the chuck with an indicator. Move the steady rest as close to the chuck as possible and then bring in the followers to touch the work piece. Then move the steady rest to the desired position on the ways.
Alternatively, you can drill a temporary center in the far end of the stock and use tailstock support. Then set up the steady rest, then turn off the temporary center. I have done it both ways depending on how irregular the stock was.

If you have stock touching the followers and test it with an indicator, the runout will read zero even if you are way off axis with the spindle.(assuming the stock is round or course)