What am I doing wrong?

[matzo]

My threads are not vertical but seem to layover to one side. Using a sharpe 60 degree cutter, compound set at 29 1/2 degrees, cutter at 90 degrees to work.

I have added some photos of my setup. The pictures of the thread were taken through a magnifying light. I am keeping the cross slide at zero and feeding with the compound.

 

[Ed ke6bnl]

I am far from an expert BUT did you use a fishtail device to set the V at 90 degrees to the work

 

[Latinrascalrg1]

Just looking at it it would appear that your cutter is not 90° to the work or your cutting bit is not evenly ground to 60° triangle so that both sides are equal.

Going by the thread work it looks like the right side is at the 60° cutting angle but the left side is at 90°.

When feeding the cutting bit into the work you do so using the compound that is set to the 29.5° so that the bit cuts only on 1 side of the bit instead of plunging the tool bit into the work at 90° which will cut on 2 sides at the same time. Hope this helps some.

Please post a few pictures of your cutting tool so we can possibly tell you more.

 

[Cobra]

I would check that your compound is really set to 29 degrees.

 

[pineyfolks]

You have just cut your first successful buttress thread. Just kidding.
I agree that you need to use a center gauge to get your tool perpendicular to your work.

 

[mikey]

Very interesting looking work piece. I assume the odd shape of the work is an artifact of the lens? It looks trumpet shaped in one picture and bent in the other.

With regard to your thread form, I suspect the issue is that the compound is set at the wrong angle. Set it to 60.5 degrees and try again.

 

[JimDawson]

Looks like a buttress thread I'm going to guess that your compound is set to 29.5° from the wrong start point. Start from the compound at 90° to the lathe centerline and rotate 29.5° counterclockwise.

 

[JR49]

My threads are not vertical but seem to layover to one side. Using a sharpe 60 degree cutter, compound set at 29 1/2 degrees, cutter at 90 degrees to work.

I believe you had your compound set to 29 1/2 degrees off the spindle axis. It needs to be 29 1/2 degrees off perpendicular to the spindle axis. Not sure if I said that correctly, but basically the way your compound protractor scale is set up, you need to set it on 60 1/2 degrees. Hope this helps, happy machining, JR49

 

[JerryK]

The cross feed stays at zero, feed in the compound ( Maybe )

 

[British Steel]

With your belly at 6 o'clock, the 29 degrees you want is with the topslide handle pointing at 5'o'clock, not 4, and the threading tool needs to be pointing directly at 12

Dave H. (the other one)