Slideway locking screw bottoms out

I've recently bought a Warco WM18 and am still in the process of checking things over.

I've met with a bit of a puzzle in the Y axis locking screws. Basically the locking screw nearer the front of the table bottoms out (i.e. goes all the way in) but even then doesn't actually lock the table. I've put a longer M6 screw in just to test how far down you need to go to reach a stop, and it is the full length of the supplied screw plus about 5mm. The female threads in the hole in question are in good condition.

I feel sure there is a simple explanation for this, but it eludes me at the moment. Any help would be much appreciated.

ETA: I should mention that even when a longer screw is inserted and it reaches a stop it doesn't very effectively lock the table.

Edited By Bill Phinn on 15/02/2020 20:14:14

If they are like some of the sieg machines then there is a small round slug that goes into the hole before the screw you may be missing it in that hole, what do the parts drawings show?

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

They usually have a tiny brass cylinder down the hole. Remove both screws and check the depth of the holes, you will then know how long the cylinder should be that just goes down the hole.

Thanks for your answers.

I've attached a scan of the relevant page. Slightly unhelpfully, it appears to depict an older version of the WM18 but I think it does show the presence of a brass pin; at least that is what part no. 14 is described as so I'm assuming the y axis is the same.

Is it possible the brass pin is in there but has dislodged from its correct position? If so, how would I go about getting it back into position and having an operable slidelock?

14 it is, you could make one out of a brass woodscrew in five minutes with a hacksaw and a file.

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

I've uploaded one photo of one of the x axis holes with the screw removed clearly showing the brass pin, and two photos of the y axis hole not apparently showing a brass pin. I couldn't swear to not being able to see it, mind you; my eyes are not that good down holes.

Obviously making a brass pin is not going to be any problem. An ongoing concern though is whether there is a brass pin in there somewhere but it has got dislodged sideways somehow only to jam up the y axis at some critical moment. Is this possible, or is there nowhere a brass pin could be hiding other than down that hole?

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

There does after all appear to be a brass pin in there, only it's very deep in the hole, so deep that it has apparently fallen into a recess in the gib strip. Not sure how to proceed.

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.

IMO the pin is (supposed to be) there to present a flat face to the gib so that no burr is ever raised. Being a tapered gib if you use a screw with any kind of point it might raise a spot on the gib which will get lifted on the edge of the hole when later you come to adjust the gib for wear. I'd re-make the brass peg or even perhaps use some lead shot in the hole so the gib remains un-marred.

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

Many thanks to everyone for your replies.

A short while ago I managed to persuade a much younger pair of eyes than mine to peer down the hole - the conclusion: I'm imagining the presence of anything brassy down that hole. Since, also, a long thin drill bit inserted into the hole appears to reach all the way to the near side of the gib, it's difficult to imagine where any brass pusher that may have been in there could have disappeared to, unless the pusher was for some reason ludicrously short.

I'm going to try and get hold of the appropriate pusher from the retailer (sorry, Mark, I did buy new) and hopefully just get on with using the machine.

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.

Most likely was never put in there at the factory. Would not be entirely unheard of with Chinese machinery. Or possibly fell out during shipping due to vibration etc and some Helpful Harry put the screw back in place but left the pusher on the floor where it lay.

.

Possibly an innovative ‘cost reduction’ exercise at the factory

MichaelG.

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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

The angle presented is only roughly 1 degree. Simply putting a very shallow concave on the end of the brass pin would be adequate, and you wouldn't need to orientate it.

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

This is similar to an experience I had when working on my WM14 mill, much smaller than the WM18 but from the same family. A quote from my website

"When adjusting the gibs and clamping screws I had an interesting problem trying to get one of the brass pads in place behind the clamp screw. Every time I pushed the pad into the hole as it approached the gib strip it would tumble through 90° and disappear. Investigation revealed that the tapped hole for the adjustable gib screw had been drilled way too deep and had intersected the bottom of the clamp screw hole. After a bit of head scratching I overcame this by blanking off the gib adjuster screw hole with a short grub screw screwed in tight and then re-drilling and tapping the clamp screw hole."

Don't know if this helps with your particular problem but may throw a little light.

John

Edited By Journeyman on 16/02/2020 10:18:11