Old Arn Rebuild--how to repair a worn shaft

[Matt Meiser]

I'm in the process of restoring an old Walker Turner 8" table saw just like this one (http://www.owwm.com/PhotoIndex/detail.asp?id=992) and have found that the arbor is worn pretty badly where the pully mounts. I'm looking for options to repair the shaft. So far I've come up with the following options:


Build up the worn area with JB weld and turn it back to the origianal diameter.
Turn the worn area down from 5'8" to 1/2" and buy a pulley for the new size.
Build the worn area up with weld and turn back to the original diameter.


Option 1 is the simplest and I'm inclinded to at least give it a try. Option 2 may compromise strength, and I'm worried about warping the shaft with option 3. My dad is somewhat concerned about the hardness of the shaft and how well option 2 would work.

I'm looking for alternate ideas or anyone who's had experience with any of these options.

[David Epperson]

When I worked in a motor rebuild shop we used an oxy acetelene torch to apply a powdered metal coating. This was then turned back to the original diameter. Not exactly welding like in your option #3, but more substantial than JB weld. You might want to call a local shop that does motor rebuilds and see if they will price it out for you.

[Ben Grunow]

Turn to 9/16 and use a bushing (assuming pulley bolts thru shaft).

Why is it worn (run with set screws loose.etc)? Have you run it this way?

I would think the JB Weld would work but if the pulley uses set screws, you might want to drill the shaft through (for bolts) to take some stress off the patch.

[Matt Meiser]

I think the set screw started the problem. I've never run the saw. The pulley that came with it is destroyed inside from running loose. I did put a different pulley on and it could probably work as-is depending on how far I push the pulley on the shaft.

[David G Baker]

Matt,
If you do not have access to the metal powder coating processs there may be other options.
A possibility, turn the shaft down in the worn area and braze or silver solder a bushing that is the size you need on the turned down area.
I have heard great things about JB Weld but have never used it.
If you decide to weld, try to keep the rest of the shaft cool to prevent it from warping, use some sort of heat sink. Use MIG instead of Oxy/Acetylene it keeps the heat localized much more than gas.
David B

[Bruce Page]

Matt, I’m just thinking out loud here. It sounds like you have access to a metal lathe. Can you do a minimum clean up on the shaft and then bore out a pulley to match? There’s no rule that says it has to be .562 or .500!

[Matt Meiser]

Matt, I’m just thinking out loud here. It sounds like you have access to a metal lathe. Can you do a minimum clean up on the shaft and then bore out a pulley to match? There’s no rule that says it has to be .562 or .500!

Yes, my dad has a metal lathe. That might work well--never thought of that. There's one part of the shaft that's gouged pretty bad, but I don't have to put the pulley on that far.

[David Epperson]

IF it's only damaged where the setscrew was, you might also look at a TaperLock pulley. File the high spots down on the shaft, slide it on and clamp her down.

[Matt Meiser]

IF it's only damaged where the setscrew was, you might also look at a TaperLock pulley. File the high spots down on the shaft, slide it on and clamp her down.

No, its much worse than that. It looks like the pully started to wobble on the shaft and hogged out the pulley with resulting damage to the shaft.

[Joe Chritz]

Not sure what the shaft looks like but is there any reason you can't just turn a new shaft?

Other than that I would turn the shaft to a smaller diameter and press fit a bushing in a pulley or go with a smaller hole in the pulley to start.

I just did something similar for a diamond wheel for a foley/belsaw. Works like a charm.

Joe

[Matt Meiser]

Joe, one end is threaded so if we made a new shaft we would have to recreate that as well. I'll try to get some pictures tonight.

[Robert Mahon]

If it were me, I'd:
1. Place the shaft in the Lathe using the shaft's centers.
2. Turn the existing shaft to a diameter just small enough to get a good, smooth straight diameter.
3. Turn a bushing to slightly press-fit the shaft and properly fit the pulley.
4. Press the bushing over the shaft.
5. Cross-drill a hole through the shaft and bushing just large enough to receive a 1/8" diameter roll-pin.
6. Press in a 1/8" diameter roll-pin.
7. Grind off any of the pin that is above the surface of the bushed shaft.
8. Smooth the assembly in the Lathe so it provides a good fit to the pulley (do not use a file to do this).
9. Re-assemble the machine.

I am hesitant to use heat of any type on shafts because too much heat may cause warping or soften of the metal.

[Rick Lizek]

1. JB Weld isn't really a repair but it's the cheapest thing you could try first depending how bad the shaft is. Might be money wasted you could use toward the real repair.

2. Turning the shaft down is the cheapest way and should be no problem with an 8" saw providing it's on the end of the shaft and not the middle. You could turn it down the least amount to keep as much metal there and rebore a pulley to fit your non-standard arbor diameter.

If it's in the middle, one way I've done it is to turn the shaft down and silver braze a split sleeve on the shaft and then turn that down. Silver brazing is often overlooked. Very high strength, that's how they put the teeth on a sawblade. Less heat problems. 1,200 to 1,400 degrees versus 2,600 degrees F to melt steel.

3. Welding can warp and distort the shaft and can cause more problems. Spray welding is the least invasive way but could be pricey. Plus there may not be anyone in the area but you could always ship it to someone. It would definitely cost more than a new shaft if you could buy one off the shelf. There are some processes that can be used with an acetylene torch but most common is a tig type torch with with a special applicator. With the acetylene torch bronze powders as well as ceramicc powders can be sprayed on different surfaces. The least heat transferable way to put a hard surface on something. I've sprayd bronze powder on particle board with no burning of the board.

4. You might be better of buying an arbor from another manufacturer and making it fit. Most arbors are pretty basic so it might take a slight modification to work. I've done it with Delta arbors on some old saws. You might try a Grizzly arbor as I'm guessing it would be cheaper.

I repair machines for a living so these are tried and true methods.

[Lee Schierer]

We get this sort of thing done fairly frequently. We have a local shop (Erie Hard Chrome) that will plate (hard chrome) the shaft and then regrind it to the desired dimension. This keeps the stregth intact and also keeps if concentric. They can even mask areas where no build up is desired. Shafts we've had done were as good as new and only took a few days.

[Carl Eyman]

I've used shops that specialize in shaft build up many times and always been satisfied.

[Cliff Rohrabacher]

Build the worn area up with weld and turn back to the original diameter.

That's what I'd do if I were serious about a rebuild. If all I wanted was to get it spinning I'd use some shim stock and a hammer