Tapered gibs

[Robin GrahamParticipant @robingraham42208]

I'm recomissioning my WM14 mill after a year of storage. There were a few spots of superficial rust on it, so I thought I should strip it down to check the ways etc were OK (they were). The machine has tapered gibs which have always worked fine, but when I had it in bits I saw that there were also brass grub screws set in the dovetails – piccy below. These don't protrude beyond the face of the dovetail, so are doing nothing. If it ain't broke don't fix it I know, so I'm not planning on fiddling with them, but I'm curious – is this standard practice on tapered gibs? I can only think that they're there to correct any mismatch between the taper on the gib and the dovetail.

Robin

[Robin GrahamParticipant @robingraham42208]

[Clive FosterParticipant @clivefoster55965]

Probably intended as slide lock screws. Tightening up would push the gib hard against the slide locking the travel. Objectively speaking imperfect engineering but my Chester Lux style mill had two such which seemed to work well enough.

Whilst you are in there do check that the adjuster screw head is a nicely snug fit in the slot in the gib. Also verify that the screw is both straight and running parallel to the gib. Problems in this area are not unknown and even small errors result in monumental frustration with a gib whose adjustments won't behave or, worse, self adjusts from too stiff going one way to too slack the other. My Chester suffered from both errors. Fortunately the female thread in the machine was in line but the screw was a bit bent, the head cut on the slant with appreciable difference in depth from side to side and a couple of mm or more excess clearance in the slot. Took me ages to finally figure out the trouble but a new, carefully made, screw transformed things.

Clive.

[Robin GrahamParticipant @robingraham42208]

Gawd I feel stupid now! They are indeed the slide locks – I'd taken the Bristol locking levers off, which I'd assumed bore directly on the gibs, and when I saw the brass bits from the 'inside', thought they were summat else.

Lesson learned – engage brain before posting.

It's nice that they put in brass slugs tho.

Robin

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