Accommodating Gib And Way Wear (bridgeport Y)

[mws]

So here’s my dilemma. I’ve cleaned up the Y axis on my Bridgeport’s saddle and knee surfaces. It didn’t look too worn, still showed some flaking. So I took a light scraping to take down the obvious dings and high spots, knowing a more intense scraping would likely be in my future.

What I didn’t expect was when I test fit the saddle I discovered that the gib needed to go in about 0.350” more than the adjuster was capable of providing. That’s about .005” gap in the way. And naturally, when fitted snug it’s way too tight at each end.

Assuming that scraping things straight will make this gap worse, my question is: Do they sell oversize replacement gibs anywhere or does one simply add a shim between saddle and gib and call it done?

Looks like I’m also in the market for a good 24”-36” cast iron straight-edge, but even the raw castings seem a tad pricey.

 

[Smithdoor]

Machine tool re-builder will use a epoxy
Look at http://www.devcon.com/products/products.cfm?brand=Devcon&cat=Metal Repair for more info
https://www.freemansupply.com/produ...d-repair-materials/devcon-bronze-putty-bronze

Dave

 

[Kernbigo]

Use 24 hour epoxy glue and a plastic shim in back, i use to rebuild machine and that is the way it is done

 

[4GSR]

You could also cut a brass or steel shim from shim stock material and use it as is or glue it with Loctite 404 adhesive.

 

[wawoodman]

How is this done? Do you put the filler in the female dovetail and machine it back to the original fit?

 

[Kernbigo]

Don't over think this it is not rocket science, just get some plastic shim stock in different thickness, find the write thickness, by putting in the back of the gib. When you get it fitted up, glue it with 24 hour epoxy and clamp it down to a flat surface, and allow a little bit for the glue to increase the thickness. You are done.

 

[mws]

Thanks for the replies. I measured the ways both quick and dirty and using the official dowel/trig method. Either way I came up with .004" that the gib cannot make up. If I scrape the ways true again and back the gib out into the first third of its adjustment range I'll end up with a .010+" shim when I'm done. I can't use, and shouldn't need to use, epoxy since the table lock needs to work through that side of the gib. I can't believe there was so much slop in a "working" machine but it ain't like I wasn't warned about 50 year old Bridgeports. Thank you again guys.

 

[4GSR]

Place a steel shim behind the gib, doesn't necessarily need to be glued in place. Let the table lock work against the steel shim on the back side of the gib. Done this several times in my past. Doesn't hurt a thing. I'm not a fan of using plastic shims on gibs. I either use steel or brass shim, or I just make a new gib. Lots of manual work, have done it a few times in my past.
BTW- I hardly ever use the table lock on my mill. I use the cross slide lock often.

 

[Kernbigo]

I have used steel shim in the past and i like plastic better for the simple reason you can remove stock from the plastic shim easier if it is to thick. You want to glue it so it remains in the proper position, rebuilt a lot of machines and that was the normal way of doing it. Making or buying a new gib can be a pain fitting it up.

 

[tertiaryjim]

Ive lately been machining new gibs for my lathe and mill/drill. After machining one side for taper, they curl like a banana.
Gotta cut them thick and straighten after each pass. Flip and do the other side until they are reasonably flat- then scrap them flat and parallel.
Lotta work! A lot can be learned doing this but it takes time and can result in a lot of frustration.
Needed to use the lathe after scraping in the cross slide but didn't have the new gib ready so I put some plastic backing on the old gib.
Used the material from a file folder and it worked great. As I had already started the new gib I completed it but was tempted to go with plastic backing for the mill.