Properly Aligning a new Z Screw

[rwskinner]

I'll be installing a new Z axis ballscrew in the 10x22 conversion and I was wondering if any of you have any neat tricks or tips for aligning it properly.

The Non-Fixed end will be installed in the bearing bore on the head stock end, which the original lead screw was driven from. Fixed end as well as the driven end will now be located at the tail of the lathe.

I haven't built the fixed in mount yet because I wanted to wait and hear opinions and take them into consideration when designing the mount.

Richard

[rwskinner]

Maybe that was considered a dumb question.... Just looking for tips.

I think I'll do something like turn down a pointed transfer punch that will fit into the lead screw bearing on the head stock end. I'll mount my Ball Screw mounts to the carrage and slide it up to the transfer punch to mark the center of that bearing. Once I machine the ball screw mount, I could put a transfer punch in it, then mark the rear mount.

That should get me pretty close. I have oversize holes in the carrage mount and the fixed end mount so I can fine tune if I need to.

Honestly, with as much flex and run out on the factory lead screw I can't see where it really has to be "that" precise, although the more precise the longer it should live.

My X Axis is only about 10" long. I ought to be able to leave the floating end totally floating without a bearing correct? Just have my fixed end bearings and ball screw?

Richard

[tauntdesigns]

Howdy Richard,

I'm not real familiar with the 10x22 lathe and what's behind the cover where the z-axis screw mounts on the spindle end of the machine.

If I understand what you're wanting to do, it's close to what I did to my 8x14 lathe.

Am I correct in my thinking?

Jack

[rwskinner]

Close but not the same as yours. I have a cast iron tranny there, and the bearing is captured internally and retained by a round, 3 screw cover plate. I think you actually had a side mount block.

At any rate, I guess I don't have to use that bearing but it's about the most true surface there. Everything else is rough casting.

My idea is, instead of gutting the old tranny, I planned to machine a new bearing retainer from 2.5" od round AL stock x 2.5" long. Drill and counter bore holes for the three bearing retainer screws and bearing bore. Remove the old lead screw, and old bearing cover, and replace the cover with this bearing block.

My old tranny stub shaft will stick in part of the bearing block on the left side but won't actually touch anything. New Bearing and retainer will be on the right side for the ball screw.

I always thought about making a mount for a lazer pointer for quick alignments but never did do that. To calibrate the lazer pointer, I could use the X3 and spot a plate with a center drill, move the Z up, stick the laser and adapter in the collet, then align the dot up with the center drill mark. Maybe two small set screws could set the X&Y alignment of the laser. The only thing is it would only get you in the ball park I would guess.

[dgoddard]

I recently finished conversion of the G0602 to CNC. Note from the photo (early stage) I took a slightly different approach by removing gear box entirely and mounting floating end in bearing block. Lined up Z ballscrew by aligning both bearing blocks and ballnut parallel to Z axis. For X axis I mounted ballnut on rear instead of mounting in original position. This avoided having to machine cross-slide to make room for ballnut.

Enjoying my 10x22. Have added indexing and replaced the ac motor with a 3ph for variable rpm.

Good luck on your conversion.