Using the Cross Slide for Threading

[Bob Korves]

What has gone unsaid in this thread is that the cross slide versus compound question is really all about keeping track of the depth of cut. When using the cross slide, what you see on the dial is the depth of cut. When using the compound, it is the cosine of the actual compound angle from the cross slide axis times the travel on the compound dial. It is easier to just use the cross slide, sometimes better to use the compound, best to know how to do both, and important to understand grinding threading tools that will work properly with the chosen method.

 

[Ulma Doctor]

i read somewhere that, at a compound angle of 30*, each .001" of travel on the compound is equivalent to .0005" of tool movement towards the work.
so in essence you are moving the dial on the compound at half of indicated movement at a 30* compound angle

 

[f350ca]

The tool is moving toward the chuck .0005 and 0.000866 toward the work Mike. Makes a big difference if threading to a shoulder.

Greg

 

[Ulma Doctor]

thanks for the clarification

 

[Bamban]

My Jet 1024 has been set up to chamber AR 223 barrels, meaning the compound has been set to bore the barrel to the same taper as the case/reamer before running the finishing reamer, and I don't want to reset compound back and forth. With that set up I thread with the cross slide. So far life is good, I thread with half nuts closed the whole time and use the full feature of the VFD and the proximity sensor, threading close to the shoulder with no thread relief.

The threads come out with nice finish. This picture of a thread adapter was the maiden run with cross slide, did not want to push to the shoulder, just enough for the internal thread relief in the muzzle break to clear.

Using this special order Thin Bit carbide threading insert I can thread real close the shoulder.

 

[bfd]

there is a thread that I have cut that requires using the cross slide the compound is set at 90 degrees so you can advance the tool bit 1/3 of the way around the thread I was cutting was a triple lead thread that I was cutting for an apprentice project so you had only the cross slide to advance the toolbit bill

 

[Ulma Doctor]

well for better or worse, here is the threading from the cross slide in delrin
1.00" long threads, .750" OD x 18 TPI

 

[JimDawson]

Looks like it worked Mike.

 

[Ulma Doctor]

i'll feel a lot better after i try the 304.
i cringe every time i thread it

 

[Ulma Doctor]

i'm still working up to 304, but here is interrupted threads on a scrap aluminum shaft.
the threads are .500 X 26tpi X 1.00" long