Single point threading

[Uglydog]

Note: I've not read this entire thread.
Check out:
http://www.hobby-machinist.com/threads/lathe-threading-several-techniques.52838/

Daryl
MN

 

[MattM]

Watched the Joe P, video. I was/am aware of that method, but still prefer to use the halfnut always in method. Seems it just eliminates one step in the threading process. I'm an amateur, amateur hobby machinist not interested in speed.

Today I cut a 3/4 x16. Took me maybe 20 minutes and it came out near perfect with absolutely no sweat. I know that's an eternity to the journeymen around here but for me that's probably a personal best.

Like has often been said, "There is more than one way to skin a coon.".

 

[Catcam]

First, you want the angle to be less than 30 degrees, never more. And that angle is measured from the cross slide direction, not from the spindle axis. Sometimes the degree markings on lathes for the compound angle are laid out measuring from the spindle axis at zero to the cross slide at 90 degrees, which will give you a 60 degree angle to the cross slide if you set it at 30 degrees on the dial. Get the compound pointed directly in line with the cross slide. That should be 0 degrees, not 90. Then swing the compound to the left as you count off the degrees until you get to less than 30 degrees. Anywhere around 29 degrees is probably fine, it is not critical unless it is more than 30 degrees which will leave a stair step finish on the right flank of the thread.

Hi For clarity. When setting up the compound to do single point threading you need to point the handle of the compound towards you, making this zero degrees. then swing the handle to the right away from the chuck, approx 29 degrees up to 29.5 degrees and lock in the compound. The compound will be used for feeding into the cut as it progresses.

If it was set up at 30 degrees from the axis of the lathe then the threads will be over cut along the axis of the thread and appear to give multiple starts or a smeared thread..

in theory using the compound or the cross slide to cut threads make little difference other than possibly more chatter on the thread if there is a big thread being cut.

 

[pstemari]

30° *exactly* would be ok, but anything over that will telegraph into the thread making the right side of the thread groove too flat.

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