Recent content by AndyPandy64

Thanks J-G. I think you have identified my problem. Helix/clearance angle The shaft OD is 7/8 but everything about the thread is ACME 5tpi. Tool geometry, apparent pitch, DoC, etc. ie 0.110 DoC. Just its a two-start thread I got all the data from the Machinist Handbook My plan was to first...

You are probably correct I measured the cross lead screw thread with a pitch gage, its a 5tpi thread. So my practice nut was a 5tpi. I was then confused then it did not fit on to the old lead screw. Eventually I figured out its was a two start 2.5tpi thread. If, on my Student 1800 you set it up...

I see you have a Colchester Student. I've got a Student 1800 and had the same problem. You are correct that the thread is a two start 2.5tpi ACME. I found out the hard way, but fortunately had just made a test nut to check the fit on the unworn ends of the lead screw I found, by accident (or...

I modelled both the cross feed screw and nut insert a few years ago and the below are links to Fusion 360 models of both the Cross Feed Screw and the nut insert in case anyone needs them Note the thread on both is not a two start ACME thread. I just modelled something Nut insert Screw I've...

I had to replace my cross slide screw and nut on my 540. You are correct, it is a 2.5tpi multi start thread. If you use a 5tpi screw you will have to turn the handle twice as much for the same distance. I've got a Colchester student 1800 and by some miracle I figured out that you can do a multi...