Malt vinegar munches rust. Scrub with a toothbrush etc, then rinse and dry

Dunking for an hour may be necessary, you'll need to judge it yourself

Robin, for light use like you need on that part I use a wood dowel with a slot in the end and a bit of fine emery strip wrapped around. Chucked in a drill motor, or even hand spun, it will polish up a bore nicely. A loose wrap works best.

Pete

Edited By Peter Krogh on 31/03/2016 04:20:01

I wouldn't normally intervene because i can barely remember how i fixed this now but i bought a similar rotary table a while back and had the same problem, initially dismantled to clean up and upon reassembly the whole thing was dead stiff, i think i can remember it may have not been the mechanism itself but the plate that holds the rotary table together on the back was bolted up too stiff, just loosened by a few turns and it was working again.

Michael W

Slight corrosion in one area that should have been well protected by oil suggests that there may be similar issues in other places. Time for a careful strip down and good clean up everywhere. With appropriate attention to any areas where the need to meet an affordable price may have prevented the sort of detail fitting and fettling that makes a high end, highly expensive, rotary table that much nicer to use.

I've seen this sort of inexplicable internal corrosion before on things put away for store. I imagine there is some sort of local contamination of either oil or the parent material letting causing the corrosion. If the item is in regular use I guess the corrosion products tend to be swept away and distributed. Hopefully collecting in a safe nook or cranny away from bearing areas.

Clive.

Good result Robin!

Roger