Jib repair on compound rest

For starters if you search around on this topic, use the term "gib" as this is how it's spelled. But most of the repairs I've seen on bits like this involve sistering in a bit of cast iron, using screws or braze or pins to hold the new piece in.

If it were me I would probably spend the 49 and scrape it to fit, not really that tough. Or, machine it out and make a bit of cast iron to braze in place, and then machine back to size. The braze is pretty strong, so even that approach should work. The trouble would be to keep the braze from wicking all over the place, and build up enough material to do what you need to do.

The gib is a tapered key type, right? Not the kind where you have a bunch of setscrews all in a line on the side of the slide, all pushing inward?

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

Yep, this Gib is a tapered key type deal, not the run of the mill Gingery style. I had thought of using a bit of cast iron to make the corner and silver solder or braze it in place. Once its there it should be more than sufficient to allow adjustment. The more I look at this "broken" corner the more it looks like it was installed new that way. The complound on this lathe has always been stiff from the get go, and all subsequent adjustment trying had failed to get it a little more free. Thats when I tore it all apart and found this piece. Origonally when I got this lathe JET told me that it was fit that way and with a little use it would loosen up. Once it gets into that tighter position it stays put, and eventually it gets to the point yu can't turn the handwheel without using two hands.

Thanks

Visit my website:

If you have previously brought the tightness to the attention of Jet and if they had act at that time and it was still under warranty they would have had to replace the part. Point this out to them politely and ask that they replace the part gratis noting their response that it would wear in. Nothing ventured nothing gained.

Chuck Pilgrim

Steve Acker in HSM or MW had same problem with his Enco Mill. Fix was drill, tap, install small screw that gib screw adjusted on.Hope this helpes. George

I was scratching my head trying to think of a sail boat with a cast iron jib.....

Gunner

'If you own a gun and have a swimming pool in the yard, the swimming pool is almost 100 times more likely to kill a child than the gun is.'" Steven Levitt, UOC prof.

Those of us who have 'em often refer to our Atomic 4's as 'The Iron Jib'...

mickey

Can you just grind the end of the gib square and flat again and use a longer adjusting screw to regain the "reach" you need for adjusting? Ken.

Could you not drill and tap a new hole further up onto the remaining part of the gib, if adding to the gib is not practical?

RJ

Why not just grind it clean/square and make a longer adjusting screw?

Roger

Roy wrote:

snip

The adjusting screws are 1/2" diameter heads, and just a slotted screw type, but the threaded portion is about what would equal a #10 thread size diameter. The head is recessed into a hole in the compound rests base casting. Drilling this hole out much deeper would make it run into the dovetail area. Its only about 1/8" . I think I will try to drill and tap the end after dressing it up, and perhaps braze it back to shape or add a piece. If tghat fails, I'll order one from Jet Visit my website:

Since Jet is offshore, it is almost certainly a 5mm screw. 5M0.8 is a standard metric coarse series thread and is *very* close to 10-32.

Ted

OK, Here's how you fix it, I've seen this on many old lathes... Cut a new slot farther down, and shim full length behind the gib. When you get the correct shim you will be back into the adjustment range. Paul

Visit my website:

Hi Roy,

I think what Paul's suggesting is to make a new slot for the adjusting screw head a little bit further along the gib (say 1/4" or so). If you assemble the gib and screw using this new slot the gib will be 1/4" further out of the cavity than it used to be, and the compound will therefore be very sloppy. You fix that and get back to the original adjustment condition by putting a suitable shim (the length and width of your gib) between the compound and the gib i.e. on the back face of the gib where the locking screw(s) bear, not between the gib and the dovetail on the cross-slide. Because the gib and compound move as a single unit there is no tendency for the shim to be worked out of its position.

Good idea Paul.

Roger

Roy wrote:

You've got a lathe.....

Mark Rand RTFM