Should I build this up with Brazing?

[rmuell01]

I didn't want to intrude on the "brazing 101" so I'm starting a new thread.

This is a very expensive wheel from my surface grinder. It is some kind of cast metal, hopefully someone can tell what.

One option would be to cut down the hub and make a new one that I could silver solder (maybe? I'm guessing here).

Second option would be to build it up with something. JB weld? or something.

There are no excessive loads on this wheel but it is constantly in use to raise and lower the grinding wheel.

 

[NASTYZEN]

Almost looks like cast Aluminum from the picture. Have you tried putting a magnet on it to see if it was steel?

 

[sr71]

Kinda looks like a cast aluminum alloy...if so a good welder would be able to TIG a repair. Cast aluminum is really hard to weld with surface prep being critical...got to get all the grease out of the pores (super clean is imperative).

Functionally I'm guessing that there is a keyway of sorts in the broken piece which will complicate the repair. I'd be inclined to cut the remaining broken piece off flush to the flat area......weld a new tube on top and if concentricity to the black bushing is critical, leave enough material to turn concentric on a lathe.

 

[rbgearz]

It could be faced off in a lathe. counterbored, and then a piece could be pressed in and then finished.

 

[kald]

Is epoxy an option?

 

[BWS]

First thought....If that came through here it would be dialed in with 4-jaw on lathe.Then,new pce turned and probably an interference with a bit of locktight.As posted above.

 

[baugie]

watch video here.....maybe will work for you...

http://www.weldingtipsandtricks.com/mig-welding-techniques-edge.html

 

[toolchaser]

+1 for BWS, face, bore , press in a plug

 

[Galaxieman]

Is that cast iron? If so, and you have the broken off piece, you can just mig weld it back on. I recently completed a similar repair to the hand crank on my mill and it turned out just fine.

 

[EvilWelder]

Looks like sintered steel to me, you can get away with building it up with TIG. I would make a patch piece, weld it in ,bore the hole true, and shrink fit a sleeve the size you need.

 

[gorilla]

I would not use any heat on that handle, I would be afraid of distorting the outer rim that the graduated dial must rotate on. I would machine a new hub and press it into the handle and maybe hold it in place with a dutch key. Does the missing piece have a keyway? It's much easier to broach a keyway through a new hub than in a blind bore that you would have if you built up the missing piece.

 

[rmuell01]

I would not use any heat on that handle, I would be afraid of distorting the outer rim that the graduated dial must rotate on. I would machine a new hub and press it into the handle and maybe hold it in place with a dutch key. Does the missing piece have a keyway? It's much easier to broach a keyway through a new hub than in a blind bore that you would have if you built up the missing piece.

I wouldn't want to warp the wheel, that's true. I don't have the missing piece, it was missing when I got the SG. there is a setscrew but I don't believe there is a keyway.

Unfortunately, this is what state my lathe is in right now.

I'm in the middle of reconditioning it. this is a pic of the ways being ground. I've got the apron/compound/cross slide scraped in.

Here's a pic of an precision angle I've just completed. It's for scraping in the dovetails of the lathe bed.

 

[RECox286]

Is the mfg of the SG still making them, or out of business ?

It is iffy that there will be enough strength left in the center hub

to bore and install a new bushing. Perhaps give a thought

to finding a new part if a sholdered bushing doesn't do the trick.

Uncle Bob

 

[philjafo]

Too bad you don't have the missing piece, just put them on and toss a hose clamp on it, would be almost as good as duct tape

 

[geologist]

I agree that it looks like sintered steel. Have you tried a magnet? Pressing in a new sleeve isn't such a bad idea.

 

[Kevin54]

If it were mine, I would cut it off, bore out the center hole a little larger, then press in a new sleeve. You could pressfit the new sleeve, then lock it in with a setscrew. The darker back would represent the new sleeve inserted into the handwheel.

 

[rsanter]

Another way to look at it
Do you have a mill or a friend with a lathe?

You could get another plain wheel that is about the right diameter preferably a litle smaller. Then machine the center out of yours to the point that you only have the outer ring left with the graduations. Then a little machining on the new wheel so the outer ring will fit on it with a light press fit

Or

Machine a hub that will fit the machine and then machine off the back of this wheel and attach to the hub with four or six smaller screw. Just like how they have center less pulleys or sprockets that you put the desired center in and bolt them together

Bob

 

[rmuell01]

after all the help I got from the forum I did a quick repair until my lathe is rebuilt. I bought some glue products from NAMES called tech-Bond and thought I'd give it a try.

put some of the adhesive on one part, sprayed on the activator to the other and pressed it in. It worked so fast I almost didn't get the part set. I used the surface grinder for three hours and so far so good.

thanks again

 

[rmuell01]

If it were mine, I would cut it off, bore out the center hole a little larger, then press in a new sleeve. You could pressfit the new sleeve, then lock it in with a setscrew. The darker back would represent the new sleeve inserted into the handwheel.

Kevin, thank you for taking the time for this drawing.

Another 4 hours on the SG and the whell hub is holding!