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torker
05-31-2006, 12:33 AM
Hey guys!
I need some advice in regards to the gib on the knee on this old mill.
The present gib (1 1/2" wide, 18" long, tapers from about 1/2" it 3/16" at the top.
It has one adjusting screw on the bottom similar to those on my mill drill but the mill drill has one screw on each end of the gib.
There's no way I can wrestle this thing (about 300 pounds or more) or fit it on my mill drill to machine a similar setup as the bottom has.
There may be a couple of spots where I could put a big setscrew that could tighten the top of the gib into the inside of the dovetail so it wouldn't shift up and down as I lower and raise the knee.
Anyone have any other ideas?
My head is tired...a very long day! :D
Thanks!
Russ

GRH
05-31-2006, 10:20 AM
Can a small keeper plate be screwed to the top of the knee with a tapped hole in it so a pusher screw pushes against the gib ???? You now have a way of stopping the gib moving up and down, on my surface grinder the gibs have a slot in them but the screw head was narrow and the gib kept moving so I
made new screws, bigger dia. head and width/thickness of head a light tight fit in the slot.

Graeme

Evan
05-31-2006, 12:31 PM
Russ,

If all you really need is to prevent it from shifting then drill a hole in the top of the gib that fits the head of a socket head cap screw loosely. Drill and tap a hole in the side where the gib fits and install a cap screw to key the gib in place. Of course, make sure the head doesn't stick out of the hole in the gib. Grind off a bit of the head if needed. BTW, the head of a 8-32 capscrew is 5/32 tall.

torker
06-01-2006, 08:24 AM
Evan, I was looking for an idea that may have already been there.
Under all the grease and grime I found a couple of broadhead screws that apparantly push in on the gib from the sides, forcing it into the corner of the dovetail. Still adjustable but very hard to get at.
Graeme...I like that idea.
Thanks!
Russ

Evan
06-01-2006, 11:54 AM
This post is to work around the date stamp problem and will throw the post off the top of the list.

pcarpenter
06-01-2006, 01:21 PM
Seems hard to imagine that the thing has been floating around all this time with the need for something to hold it in place:)

I assume you have the gib out and can verify that the head of the adjustment screw does not ride in a slot in the edge of the gib as is common. that scheme holds it in place without the need for anything else.

Since you found the side adjustment screws, I assume it is not tapered in two dimensions...as is also common. The double tapered gib needs movement in only one dimension to tighten it in two dimensions. If it has those side adjustment screws, then there should be no need to clamp it in place in some other fashion. If everything is adjusted right, it ought to stay. The type of gib that has side adjustment screws like that usually has indents that the screw points ride in. When properly adjusted, it won't go anywhere on its own.

Paul