Cutting internal threads on Sherline lathe

[mikey]

You could make the adapter shorter if you choose. The ones made by A2Z to fit the Sherline mill were only about 3/4" long. Most of that length was threaded into the Criterion head, with maybe 3/16" sticking out the back of the head in a hex configuration. Worked well.

 

[BiggerNoise]

Ooo, that's nice.

I think I'll wrap this one up (it will be shorter than the picture, I haven't even started to lay out the criterion side). But I'm definitely intrigued by having the inside and outside threads overlap. Maybe I'll practice Rev B in aluminum.

 

[mikey]

Doesn't have to be a hex, either. Round with two opposing flats would work nicely, too. Just try to keep it short to improve rigidity.

 

[BiggerNoise]

Had a blowout. The drive dog pin on the lead screw extension popped out.

It looks like it's just a press fit. Is there a standard size machine screw that I could run in there to get a more reliable hold?

 

[BiggerNoise]

If anyone finds themselves in the same predicament a 4-40 set screw is wonderful

 

[BiggerNoise]

And, Rev A is complete:



On the mill with the boring head (pseudo blued the adapter):



Now I just need to learn to use the boring head

 

[mikey]

Very nice head!

 

[Django]

I am late to the party and still tooling up my Sherline lathe and mill. Using a compound to cut a thread reduces the chip load and being that internal threads use a boring bar with reduced rigidity, it would be nice to be able to feed in at 29 degrees with a threading bar. My solution is fairly simple and uses an inverted toolpost. There are two holes in the upper portion to access the 10-32 set screws. This one purposefully holds the bar .002 above center. It will hold boring bars with .375 or .3125 diameter shanks. It is primarily used for internal single point thread cutting, but it is capable of boring at any angle. I will use bushings to hold smaller bars. It has been tested and works well.