Compound slide feels gritty

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dml66
Posts: 41
Joined: Fri Apr 29, 2022 8:21 am
Location: SW Washington State, Steelhead Country

Compound slide feels gritty

Post by dml66 »

As I'm getting to know my new-to-me lathe, I've come across something I can't sort out. The compound slide (the one I can rotate to different angles) feels like it has sand in it when turned in and out. The only way I can reduce some of that feel is to relax the gib screws to the point where the tool post is no longer rigid; I can wiggle it with my hands.

The cross slide on the other hand, feels like butter, and it's tight in the dovetail, quite rigid.

I removed the gib and noticed some surface imperfections, particularly on the edge which engages the narrow part of the dovetail, and removed them beyond visibility by stoning the gib down to 1500 grit; It still feels like sands' in the action when turning.

I realize this machine ain't no Leblond but, if the cross slide can punch above it's weight class, I don't see why the compound can't as well. What sort of things should I be looking at to try and improve the compound slide's feel?

Thanks.
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10KPete
Posts: 440
Joined: Wed Sep 30, 2015 5:29 pm
Location: Nordland, WA, USA

Re: Compound slide feels gritty

Post by 10KPete »

Start by stripping, cleaning and detailing. That will reveal the issue and probably solve it.

Pete
Just tryin'
davidhayes
Posts: 12
Joined: Sun Aug 16, 2020 7:44 pm

Re: Compound slide feels gritty

Post by davidhayes »

per chance, would this be a Chinese lathe. Does the gib have a ground surface facing the none sliding surface? I think you may have the same situation I had with my 12x36 Enco lathe. If so,flip the Gib over with the notch down and hold in with your fingers and adjust. It appears they ground the adjusting
screw notch on the wrong edge of some of the Gibs and installed them anyways. If that fix's your problem, be careful when grinding the new notch.
dml66
Posts: 41
Joined: Fri Apr 29, 2022 8:21 am
Location: SW Washington State, Steelhead Country

Re: Compound slide feels gritty

Post by dml66 »

So far I've stripped and cleaned the parts, ran some valve grinding compound through it, then cleaned and lubed. I'd say it's 50% smoother than it was but still not even close to being as smooth as the cross slide.

I'll check the gib next per davidhayes suggestion, nothing surprises about this specimen.
plumberzpieco
Posts: 60
Joined: Wed Oct 06, 2010 10:32 pm
Location: north east ohio

Re: Compound slide feels gritty

Post by plumberzpieco »

Normally you’d blue the surfaces to see where your contact points are and scrape it. Plenty of videos on machine scraping to kill time.
plumberzpieco
Posts: 60
Joined: Wed Oct 06, 2010 10:32 pm
Location: north east ohio

Re: Compound slide feels gritty

Post by plumberzpieco »

Forgot to add, what’s the condition of your screw and nut? Do you have a thrust bearing or some form of bushing/washer arrangement on the screw too? I just made a new nut for my Yam/Cadillac compound and got new thrust ball bearings, two of them, and it made a huge difference.
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