Gib Strip Positioning

[Peter G. ShawParticipant @peterg-shaw75338]

I am making new gib strips for my Minimill/X2 clone and have taken on board all the information shown elsewhere about domes/ball bearings/dimples etc.

 

Fairly obviously, one wide face of the new gib slides against the sloping portion of the matching dovetail and the other wide face has the gib adjusting screws bearing on it. But what about the narrow faces?

 

One narrow face will be in the corner of, and will move with, the female dovetail, but what about the other narrow face? Should this be clear of the relative sliding surface, or should it act as an additional bearing/sliding surface?

 

The new gib is made from unknown steel but thought to be fairly tough as it came off steel used for constructional purposes. The dovetails are cast iron, and as they can be easily scraped, are not hardened. Also, the slide on the non-gib side are somewhat wider than then that on the gib side.

 

This particular new gib, although an unknown steel, is intended to be disposable if necessary as this, being the first gib to be remade, is somewhat experimental. I do have a length of EN3B steel specifically bought for this purpose if it is felt that this would be better. But, if the unknown steel does indeed work satisfactorily, then I would leave in situ.

Regards,

 

Peter G. Shaw

[Peter G. ShawParticipant @peterg-shaw75338]

[blowlampParticipant @blowlamp]

Keep the narrow face of the gib strip clear of the part of the dovetail nearest to it, as there’s no meaningful way it can provide any support.

 

My prefered approach if possible is to use a stout pin in the strip at each end, such that they are tight in the casting but free in the strip.

 

This locates it nicely and removes the tendency for the gib to wedge on the cone-shaped tip of the adjuster screw when moved.

 

In addition, I drop an angled pressure-pad (usually 60 deg) down the hole, followed by the adjuster screw which has a spot of thread locking compound on the threads and do away with the locking screws.

 

 

Martin.

[Peter G. ShawParticipant @peterg-shaw75338]

Thanks Martin.

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