9x20 Cross Slide Lead Screw

[savarin]

I have a lot of backlash in my cross slide lead screw so I thought I would have a go at making the delrin nut.
As I will have to dismantle the cross slide to do this I thought I might as well make a new lead screw, thicker, longer and with bearings in the front.
So, decision time.
If I make the lead screw with a 1mm thread pitch then one complete turn will advance the cross slide 1 mm.
therefore each division of the dial will be 0.02mm instead of 0.025 as it is now.
I think I will use a 10mm dia shaft.
The question is - will a 1mm thread pitch be too fine for this application.

 

[hman]

I don't think that small a change in pitch will do any harm. The main result would be that you'd have to turn the crank 5 times instead of 4 (or some fraction thereof) to get where you want to get. Just very slightly more tiresome, but no big deal.

Other factors to consider - you'd have to mentally convert the scale readings on that one dial, but not on the others. Then again, the compound's leadscrew is already metric, but the dial reading in pseudo-inches is already a kludge. If you did go with a 1.25mm pitch leadscrew (maybe 8mm x 1.25mm or 10mm x 1.25mm) the dial would continue to read the same (slightly kludgy) way as it does now, so you'd experience no change in behavior.

Then again, if you had a DRO on the slide, you wouldn't have to worry about the exact pitch, or any periodic or cumulative errors.