Lathe Cross-Slide Lock

[Susquatch]

But I was more apprehensive of buggering of the gib.
So I tried this first & it worked. To recap = the brass angle mates the gib angle & presses laterally. Yes its bending the gib, but I would guess very little just based on the existing sliding fit.

Other than marring of the surface with a turning screw end, I wouldn't worry about damaging the gib. As you say, it's already a close fit and can't really bend much at all. The main locking force isn't the wedge or the screw anyway. It's the fact that the dovetail on the opposite side locks across its whole length that locks everything up solid.

When I install my DRO (hopefully this summer) I'll take a really close look at making a wedge arrangement for mine if only to reduce the marring that will inevitably take place with a lock screw that is turning against the gib.

 

[PeterT]

That's true, bite marks are unsightly but mostly harmless because they are on opposite side of critical sliding surface. But an undesirable secondary issue is when you torque a plain screw edge against the gib strip, it can have enough torque to displace the slide itself. I've proven this to myself many times on both lathe & mill with same mickey mouse system. But its really evident when you install DRO which records the event. Set DRO to 0.0000", lock table, DRO now says 0.0025". That's a bad thing. Locking is not just about securing the slide, its about freezing a particular position during a machining operation.

 

[Susquatch]

I've proven this to myself many times on both lathe & mill with same mickey mouse system.

Yup. Absolutely true. I've seen it many times too. So ya, that's gotta get fixed!

Remember our discussion about gibs rotating upward because of the adjustment screw? I think we wore out everyone else's patience on that one, but it was an absolutely great discussion.

I'll never be able to look at a gib again without remembering all that mental geometric acrobatics! Might even be why I had a stroke shortly afterward! LOL!

 

[Mcgyver]

I also would not worry about damaging the gib. I've seen the arrangement that Robbin showed, and also set ups like the sketch below with a brass pad. Below imo would be the easiest to implement. On straight gibs, instead of tapered, you can just make a flat counterbore into the gib with a flat bottom drill as the gib doesn't move relative to the lock

 

[PeterT]

That's essentially what my brass shoe does. Actually because (at least on mine) the threaded hole is same diameter right through, maybe a ball end might serve the same purpose since its just translating the force to the broader gib strip area anyways. I just like the idea of matching angle & wanted to work with existing M6? hole if possible. My RF-45 mill had 2 lock screws spaced apart. Probably a few ways to skin the cat.

 

[thestelster]

Ok ladies and gentlemen (do we have any women in this group?). It works!! Doesn't need much tension and locks up solid. I couldn't budge the cross-slide with all my weight.