What are some possible causes of crooked threads?
What are some possible causes of crooked threads?
(OP)
I have this machine that is threading tapping lock nuts at a defect rate of ~1800 PPM. The thread perpendicularity spec. is .005" and the majority (85%) of the parts fall within the lower half of that.
I've attached a picture of the machine, it has a loading station, chamfering, tapping, and unloading. The part can move approx. 1 mm when seated in the fixture, this space is needed for the loading operation. There is nothing holding the part down while the tapping operation occurs.
So, please take a look and let know what you think, I'm getting really tired of having crooked nuts. (sorry couldnt resist)
Other info:
1018 material
M36 x 1.5 threads
part is 5 mm thick
fixtures are flat and parallel to table
I'm thinking possibly:
Parts need to be held down while tapping?
Possible that a chip from chamfer station curls under the part tilting it?
Thanks
I've attached a picture of the machine, it has a loading station, chamfering, tapping, and unloading. The part can move approx. 1 mm when seated in the fixture, this space is needed for the loading operation. There is nothing holding the part down while the tapping operation occurs.
So, please take a look and let know what you think, I'm getting really tired of having crooked nuts. (sorry couldnt resist)
Other info:
1018 material
M36 x 1.5 threads
part is 5 mm thick
fixtures are flat and parallel to table
I'm thinking possibly:
Parts need to be held down while tapping?
Possible that a chip from chamfer station curls under the part tilting it?
Thanks





RE: What are some possible causes of crooked threads?
RE: What are some possible causes of crooked threads?
RE: What are some possible causes of crooked threads?
RE: What are some possible causes of crooked threads?
RE: What are some possible causes of crooked threads?
At only 5mm thick, you shouldn't have to worry about stretching the thread as long as the feedrate adjusts to pitch once the thing digs in. Your first couple of threads are incomplete anyway, and the tap will clean them up nicely as it finishes through.
Good luck.
RE: What are some possible causes of crooked threads?
RE: What are some possible causes of crooked threads?