Hi friends,

I got me a case of the jumpin' gibs,

I'm making a miniature milling machine and the vertical plane uses a dovetailed slide which holds the knee by a gib strip, this has 4 grub screws to nip up the slide, i spotted through with dimples on the strip and rounded off the screw head, but whenever i tighten them up, it tries to hop out!

Perhaps the screws are touching close to the edge of the gib and it's throwing it off. I'm thinking of placing two hold down screws ontop of the exposed area of the gib to keep it in it's place but, do you think that will work?

Michael W

Ah it's ok i've fixed it.

The dimples are nearly completely aligned, i sandwiched the whole thing together with a G clamp to spot through and make sure they were right in place.

Here is a crude illustration to show you whats going on;

The writing is a little small but i hope you can see it,

The gib is dislodged from it's seat whenever i tighten up the grub screws (it's pushed up and away).

My solution was to make two steel "finger plates" as i call them. with 1 hole in the middle and another at the top. One is tightened right up against the body with a socket screw and the other is left to apply pressure to the top of the gib to keep it in place. Unorthodox but seems to be working and i can't think of another way to make it stay there.

Michael W

Ps. i only just caught sight of your post Neil, but it makes sense i dont know why i didnt think of that. I'll know in future what i should do!

Edited By Michael Walters on 13/04/2016 13:33:52

You're all right, and you've identified the source of the problem, thank you.

But the solution isn't quite so easy, the gib is pushing onto an open planed vee, the cross slide image shows the Vee ways both closed. Im pretty sure i've made the drawings to spec, why they have designed it this way i'm not sure, it isn't possible to insert screws on the left hand side because the column is dovetailed both sides. I'm coping on my solution for now.

I think what you mean is that the form of the bed dovetail needs to be reverse so that the gib is pushing onto a closed surface.

For eg. On the same model, there's a small bed stop that needs to be 20.54mm long, with a slot most of the way down the body to 17.75mm, then an M5 hole needs to go through below that, but i've only got less than 3mm of room left? it's not a critical part but the measurements just don't add up, it's very frustrating when the way it's been drawn just doesn't make sense in reality and you end up scrapping something.

Michael W

Edited By Michael Walters on 14/04/2016 09:51:04