If the locking screw pushes on the gib strip there ought to be an intermediate "pusher" rod with one end angled to match the gib strip and the other flat for the screw to push on. Around 10 – 12 mm overall length sounds about right as the length of such devices usually seem to be about twice the screw diameter.

Easy to make one if need be.

If the manual has a parts diagram its worth looking at to confirm or deny the supposition.

Clive

Jason keyboards faster!

Edited By Clive Foster on 15/02/2020 20:19:51

Bill

I have a WM16 and it has a brass plunger which the locking screw presses on.

I have just had a look at mine and I can see it when I remove the locking arm. It’s about 10mm in from the end.

Perhaps yours is missing this part.

Stuart

Bill,

I would think that all there is, is a drilled and tapped hole. Why would the maker create a cavity at the bottom and what for? Cannot think of any logical reason for an apparently useless cavity. Suggest you go ahead with making a brass slug and follow it up with the locking handle. Should work OK, at least I hope so. Just seems like an omission during assembly. Good luck, hope all goes well.

John

it would be almost impossible for the pin to escape from the machine side of the hole, since the gib is in the way. your options are:-

1. Have a shout at Warco and demand a prompt supplie of the missing pin.
2. pull the saddle off the base, push out the pin that's there and manufacture an additional one out of whatever brass/bronze you can find.
3. turn a brass pin of the right diameter to fit (use a drill or similar to find diameter), file to match the dovetail angle and live with it.
4. poke a drill down the hole to cut a conical face on the corresponding bitof the gib and use a longer screw fronted by a bearing ball of suitable diameter or a conical point to match the crater in the gib.

All of the above are valid methods, and there will be others. If the machine is brand new, No1 is the approved answer. If the machine is "pre-loved", then 2 followed by 3 followed by 4 would by my choices. I have used all except No1 (new machine, What's one of those?).

In the meantime, just use the locking screw that does work. If the gib is adjusted with minimal clearance it should be sufficient for locking the slide without any problems.

Warco site says the WM18 has taper gibs. If so the pusher must have an angled end matching the gib & dovetail angles.

Flat ended pusher or intermediate ball will distort the gib.

Obviously you cant have a hole or recess for the pusher to work in because that will prevent gib adjustment.

Best to strip it all out and look. More tedious and heavy than difficult.

Clive

Getting the angle of a push rod absolutely correct is made a bit tricky by the taper of the gib. However, many well-respected machines get around this problem by interposing a ball bearing between a flat-ended push rod and the gib strip. Of course, point contact is not ideal, but, in practice, taper gibs are stout enough not to be distorted (and there's nowhere for them to bend), in spite of Clive Foster's warning. At worst, a small dimple will be produced on the 'back' face of the strip, and it will take a lot of gib strip longitudinal adjustment before any raised lip of the dimple bears on the slide's gib-strip-bearing surface.

.

Possibly an innovative ‘cost reduction’ exercise at the factory

MichaelG.

.

.

To quote from your recent post on the ‘Screwcutting’ thread:

But I always bear in mind the words of Nevil Shute, […]

'An engineer is a man who can do for five bob what any bloody fool can do for a quid'.

Edited By Michael Gilligan on 16/02/2020 07:54:24

Or maybe the brass mine is shut down due to coronavirus.

Concerning the risk of gib distortion it depends on the style of gib.

A conventional thin gib can and will distort if the locking force is applied over a small area such as by ball or radius end. The action is also poor as not only do the very localised locking forces tend to pick up on minor imperfections in the machined surface but the whole action is inefficient. With a tapered end to the pusher the gib the gib should be firmly pushed up into the top of the female dovetail as well as against the male dovetail on the slide. Mechanically much firmer and the locking action needs much less force on the screw.

Not theory. I have seen and replaced gibs that sprung into a visible bend when removed due to small area locking. I have also re-worked gib systems so the locking screw, and adjustment screws in the case of ordinary plain gibs, act to push the gib up into the top of the dovetail recess. After such effort everything works much better with reduced working clearances and the slides lock more firmly with less force. Considerable effort needed to get things right but, I felt the improved performance well worth it when re-furbishing an older lathe or one where affordability to the first buyer meant some engineering infelicities had to be accepted.

Pete says that the angle presented by the outside of the gib is only 1 degree, much less than the dovetail angle. This can only be so if the gib is much thicker. Obviously a thicker gib is far less likely to bend but pushing on a reasonable area seems a much beter way of going about things.

Clive

A plain brass cylinder is all that you want, it pushes against a flat surface in this type of mill.