PDA

View Full Version : How to repair gib adjuster slot?



Peter.
09-08-2011, 07:43 AM
I'm looking for advice on how to repair this gib. It's quite small - for scale the thread of the adjuster is M4, OD of the large diameter is 8mm.

How can I repair the slot so I can make the adjuster serviceable? I have access to a pretty damn good welding guy with a tidy TIG. I'm thnking grind or file off the high spots, build the edges with tig or braze then file the slot back to width. Would this be an acceptable repair?

http://peterrimmer.myby.co.uk/images/gibrepair.jpg

Your Old Dog
09-08-2011, 07:53 AM
Not trying to be flip but hit it with a hammer. The secret is to use a light weight hammer and a little patience. Gunsmiths know the can peen buggered up screw heads by lightly bending the metal back in and then re cutting the screw head with a warding file. You should be able to clean it up enough that it will be serviceable for a long time.

Welding over the bad part and re cutting the notch would be another answer but move involved in my estimation.

Good luck.

Davo J
09-08-2011, 09:12 AM
What about opening up the slot to remove the damage, then either make a new screw with a wider collar, or get your mate to build it up with weld on the unthreaded side and machine it back to size.
Welding on that side of the adjuster wouldn't hurt anything.

Dave

Carld
09-08-2011, 09:23 AM
You have a situation where the collar is not going into the slot deep enough. You can have it welded up but it will just happen again unless you can figure out a way to get the collar full depth into the slot. Perhaps you may have to make a screw with a larger collar and open the recess it fits into.

If you just weld it up and put it back it will fail again. You need to find out why it failed and correct it.

portlandRon
09-08-2011, 10:27 AM
Can you reverse the piece (flip end for end) and cut a new slot in the other end?

Carld
09-08-2011, 10:33 AM
Gibs like his are tapered and only fit in one direction. Some gibs are the same size the length of them and use snubing screws along the length of the gib to adjust it. Those usually have a pin that keeps them located.

aboard_epsilon
09-08-2011, 11:14 AM
Gibs are made of cast iron ..although that ones looks too ductile to be it.

i would only risk braise on them if they are

all the best.markj

hitnmiss
09-08-2011, 11:19 AM
Looks pretty small but how about milling off the damaged area flush to the grove and drilling and tapping a 2-56 socket head cap screw so the head is tangent to the old groove.

Peter.
09-08-2011, 01:32 PM
You have a situation where the collar is not going into the slot deep enough. You can have it welded up but it will just happen again unless you can figure out a way to get the collar full depth into the slot. Perhaps you may have to make a screw with a larger collar and open the recess it fits into.

If you just weld it up and put it back it will fail again. You need to find out why it failed and correct it.

Funny you should say that Carl - I just noticed something odd. It looks to me like the adjuster groove has been machined in the wrong side. Reason I think this is because the frosting is all intact on the side that has the oiling groove but is worn away on the side that just has the plain through-hole showing. Now surely the oiling groove should be on the face that slides?

http://peterrimmer.myby.co.uk/images/gib1.jpg

http://peterrimmer.myby.co.uk/images/gib2.jpg

Both were packed with dried out gunge so I guess that could account for the gib sticking and the wear in the slot.

Carld
09-08-2011, 02:17 PM
Yes, I think your right, the oil groove should be on the rubbing side. I have run into the problem of the collar not being large enough to fully engage the slot on even quality lathes and had to make changes to make it right.

Peter.
09-08-2011, 02:24 PM
Well then, since the gib measures a taper in only one plane and seems to be a parallelorgram in cross-section I guess the cure for both problems is to re-cut the adjuster groove on the opposite side.

Now, if only I had a working miniature precision horizontal milling machine to do it with :D

aboard_epsilon
09-08-2011, 02:50 PM
Is it one of those "Childs" milling machines you have there .

lets see a picture of the whole thing please .

all the best.markj

Don Young
09-08-2011, 09:21 PM
Well then, since the gib measures a taper in only one plane and seems to be a parallelorgram in cross-section I guess the cure for both problems is to re-cut the adjuster groove on the opposite side.

Now, if only I had a working miniature precision horizontal milling machine to do it with :D

You probably do have one. It's called a file. Could probably have it done before you could get it set up in a mill. Dremel type tool should do it too.

Peter.
09-08-2011, 11:06 PM
Yes I have files of course :)

Mark, its a Rawyler mill. I did take some pictures before dismantling it but my digital camera has had a benny and saved all the photos with lines across them like a bad tv picture. Looked ok on the viewfinder but no good on the sd card.

aboard_epsilon
09-09-2011, 06:16 AM
So its this then

http://www.lathes.co.uk/rawyler/

..looks a lovely little thing ..nice .

all the best.markj

quadrod
09-09-2011, 06:51 AM
The gibb was installed in the correct position, the groove on the oil hole is so oil can get into the hole as the gibb is adjusted through its range during its life time. As you move the gibb the oil hole will not line up if it only has a small round hole to pass oil through. Clean up the damage on the gibb and make a new screw with a taller collar to fit the slot in the gibb.

Peter.
09-09-2011, 07:33 AM
The gibb was installed in the correct position, the groove on the oil hole is so oil can get into the hole as the gibb is adjusted through its range during its life time. As you move the gibb the oil hole will not line up if it only has a small round hole to pass oil through. Clean up the damage on the gibb and make a new screw with a taller collar to fit the slot in the gibb.

Yes, that makes alot of sense, especially as I since noticed the other is the same.

Making a new screw will be easy enough, that is what I shall do.

Peter.
09-09-2011, 01:38 PM
Well a bit of file work and a new adjuster and all is rosy in the world of tapered gibs :)

http://peterrimmer.myby.co.uk/images/gibnewslot.jpg

Bit of a cruddy image, but you get the idea. Thanks to everyone who replied - sometimes you just need a bit of encouragement and jobs become really simple.

Pete.

Davo J
09-10-2011, 09:10 AM
Good to see it worked out for you.

Dave