Manual Threading with Compound vs CNC without Compound

I have a question on Manual vs CNC single point threading. As I understand it, in manual threading, the
Compound is set at an angle of 29.5 degrees. As the thread is cut, successive cuts are made by advancing
the compound, not the cross slide.

Since the CNC machines, at least the ones I have seen, do not have a compound, the only way to make the
next cut is to advance the cross slide.

So, does a CNC machine actually engage the next thread cut at a variable point in relation to the indexed
point of rotation, thereby replicating the use of a compound?

I hope this question makes sense. I can see it in my mind. It's just difficult for me to put into words.

Big battle over the whole 29.5 deg thing. But yes, cnc have infeed patterns. Some replicate the 29.5, some do a zig zag pattern, some feed straight in. Depends on the thread type you want to cut. It's usually a preparatory code in your threading cycle.

I don't know too much about it, but a quick google search revealed that you can use different g codes and sub routines for different styles of cutting threads, some feed in at 29°, but it all depends on what codes are supported by your machine control, and if your using CAM or not.

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Thanks "underthetire" and "Dylwad." That answers my question.
Looks like I need to investigate the G and M codes.

Do you know what the reasoning is behind the 29.5 degrees?

I would suggest getting a book such as Peter Smid CNC programming.
The compound infeed the .5 degree difference avoids rubbing of the tool and excessive tool wear.
G codes are fairly standard and vary as to type of machine, Mill,Lathe, Plasma, EDM etc, M codes are dependent on the MTB and can vary between the same types of machine.
Al.

Thanks for the info Al. I'll checkout the book.