Friday, January 23, 2015

Lathe: Leadscrew Handwheel

One of my biggest problems with the lathe is the carriage hand wheel isn't very precise for Z axis movement; it's hard to always stop it exactly. I don't like using the compound for fine Z axis movement since while carriage has a DRO on it, the compound does not. Also, I want to remove the compound eventually and replace it with a solid block of steel; the compound reduce rigidity of the system and I only use it for threading operations.

I know if I could attach a hand wheel to the leadscrew then I could put the leadscrew in neutral, lock the half nut, and slowly turn the leadscrew to move the carriage.

I decided to extend the leadscrew shaft past the pillow block to make a mounting point for the hand wheel. I removed the leadscrew, chucked it in the lathe, and drilled a hole in the end. It's already been center drilled which made things easier. I then took 1/2" steel rod (stolen out of an old ink jet printer) and turned down the end of it to the same size as the new hole in the leadscrew, making sure to leave a precise shoulder. After mating the rod and leadscrew together I welded around the seam, and then turned the weld bead down in the lathe.

Leadscrew extension sitting beyond the pillow block.
I bought a hand wheel from Amazon: Since it had a 10mm bore I turned the lead screw extension down to 10mm. I took the hand wheel and drill and tapped three holes in it to accept set screws. After positioning the wheel where I wanted it on the shaft I installed the first set screw fairly hard in order to mark the shaft well. I then remove it and the hand wheel, turned an extended nose on the set screw, and drilled a shallow hole at the marked spot on the shaft. I then reassembled everything and made sure the set screw seated into the hole. I then installed the other two set screws.

It ended up working really well and I now have easy fine Z axis adjustment.

I left the shaft slightly longer than necessary to allow for future adjustments.
The new hand wheel set screws are visible.


  1. Just found your blog via Home Model Engine Machinist forum. I am considering a mini-lathe and X2 mini mill myself and your journal of improvements is quite helpful.

    One question. If you had it to do over again, would you just buy the LMS Hitorque 3990 mini-mill which already comes with the belt drive, gas strut, solid column, larger table instead of upgrading a stock Grizzly?

    1. I didn't set out knowing I was going to do all these upgrades, they just kind of happened organically as I started using the mill. At the end of the day, it would have been cheaper to just buy the LMS HiTorque 3990. However, if I had to choose between buying the LMS 3990 or the Grizzly with TouchDRO, I would go Grizzly and TouchDRO without hesitation; the DRO makes that much of a difference.