Rusty Lead Screw

[CJ5Dave]

I am changing out the X leadscrew on my Bridgeport to do away with the defective geared power feed. A friend had this apparently new leadscrew, the right length, sitting in his shop. He was not sure where he got it or how long he had had it. It was wrapped in fabric but had some surface rust. I have cleaned it up with Evaporust as far as it will go, The threads on one end have some rust you can feel on the top of the threads. the other end cleaned up OK. Not sure where the contact and wear area is on these. Can I use some 600 grit and clean this up to preserve the nut? This would not damage the edge contact area of the threads. Is the diameter critical, or just the edge screw wear?

 

[CJ5Dave]

 

[whitmore]

Install it. There's a few milli-inches looseness required for lubrication, so it isn't
a critical dimension, and you don't have any reason to believe the thread uniformity is
compromised. After installing, you can test the full travel for backlash problems, and
if the half-nuts are adjustable, take up that micro inch that was lost...
A bit of texture (pitting from the removed material) will hold your lube better, anyhow.
From the pix, it hasn't lost its surface finish.

If I find a lead screw in some corner of my garage though, I'm gonna paint it with boiled linseed
oil before rewrapping it; thanks for that hint.

 

[benmychree]

There is clearance designed in between the screw OD and the root diameter of the nut threads; de rusting the screw OD will make no difference in the accuracy of the screw/nut assembly, only the flanks of the thread assembly do the work. to a great extent.