Gib position

Maybe it was worn and the dovetail behind the gib was the only good one left.

John H stelde de volgende uitleg voor :

Very intriuging question. One could also wonder why headstocks are always to the left. As most people are right handed, it seems easier to hold the spanner left and turn the set screw with the right hand.

More likely it's easier to hold the chisel with the right arm, pushing it toward the headstock. Before 1800 hand-held chisels were used on metal lathes too.

Take this with a shovelful of salt (useful in the snow) - most turning operations will be towards the chuck, putting the cutting force against the headstock-side dovetail way - the gib will have a (slightly) smaller contact area so a higher rate of wear on gib and dovetail if the force is applied to it, and any slackness in the gib will allow some movement of the cross-slide relative to the saddle if it's taking the load from the cutting forces? So... reduced wear, better accuracy?

Dave H. (the other one)

that I have.

A more fundamental question is, what's the difference between the normal and gib sides?

I don't really know, but speculating..

the normal side, when in compression (no slop), is better at handling forces directed into it, without losing accuracy, especially when those forces are in a wide range or when they are large.

So if, as is more common, you work towards the chuck, any lateral forces will be better coped with if the normal side is towards the chuck.

?

--Peter Fa9irbrother

The saddle and compound tapered gibs on my 1965 South Bend are on the tailstock side, which takes the lateral pressure when cutting towards the headstock. I cured most of the slop in the compound slide by surface-grinding the bottom of it, and a little by blueing and filing the gib. The other surfaces had much less measurable wear. jsw

sorry, I don't understand that. The cross-slide could have a gib on the tailstock or headstock side, as it is at right angles to the head/tail direction, but afaics not the saddle, and not usually the compound.

which takes the lateral pressure when cutting towards

I don't understand that either??

-- Peter Fairbrother

he that I have. On most lathes the crosslide gibs are normally on the side farthest from the chuck. Is there any reason why the gib should not be on t he side nearest the chuck? Thanks. John H

Thanks for the replies.

I think Dave H has come up with the most logical reason.

The crosslide in question was marketed as an alternative crosslide. It had no compound rest but two toolposts, front and rear. It was for use as a ? mini capstan? lathe, able to do two operations.

It looks as though I will have to transfer the gib to the other side, when I have time!

John H

The compound's gib adjusting screw is to the right of the compound handle and dial. There is a similar screw indistinctly visible under it on the "C.R. Base" , South Bend's name for what I think you call the cross-slide. That gib takes up play between the C.R. Base and the Saddle top. Both are on the tailstock side when the compound is swiveled to 29 degrees as shown to cut threads.

This is mine. The gib screws are out of sight to the right.

jsw

On Thu, 24 Jan 2013 18:59:07 -0500, "Jim Wilkins" <

What sort of tool post is that please?

Bill H Derby

It is a Swiss Multifix. I bought an incomplete set cheap and filled it out with Chinese clone toolholders which fit it perfectly.

They claim 0.01mm long-term repeatability (Wechselgenauigkeit), which my lathe won't prove, but a removed holder goes back to within a few ten-thousandths of an inch worst case.

Rotating the toolholder is very handy with hand-ground HSS bits, not so much with carbide. jsw