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Help getting Powermatic 87 back in service

bobbyf

Plastic
Joined
Sep 29, 2022
Hi Guys,
I posted this in the metalworking forum and someone suggested that I might get more help here. I’m hoping you can help me out with a 1967 Powermatic 87 band saw.
It seemed to be in good shape when I bought it, I should have looked harder.
The most interesting issue is the lower wheel. It’s a cast wheel that’s supposed to mount on the transmission output shaft with a keyway and lock screws. The wheel itself was cracked (wish I had seen that!) so had to come off. Turns out that the lock crews were missing and the threads were gone on one side like maybe someone drilled them out. Instead of fixing that, I think they took the transmission apart, turned the shaft, added an oversized bronze bushing and pressed the wheel on. It doesn’t make a lot of sense but the bearing on the output shaft looks newer – maybe they were in it anyway?
I brazed the crack in the wheel. It’s 10-20 thou out of round and won’t fit in my lathe. Is that something to worry about? Also puzzling on how to get it back on the shaft.
Even if I find a new wheel, I'd have to replace the tranny shaft along with it which also implies gears and bearings. I'm not opposed except for price and availability so will probably have to make do with the one I have.
The rest of my issues are mostly parts. The tranny has a few gears that are worn to the point of being sharp. I can’t find a reference for the gears anywhere.
I’m still trying to cross reference some bearings etc…
I would appreciate any thoughts on the lower wheel situation and advice on parts sources.

Thanks!!
 
Nice machine.
Pictures would help.
Bandsaw wheels really should be "perfect" since the band will throb in the guide as it bangs side-to-side every revolution.

OTOH if you use it primarily for metal cutting, the out of round will probably be OK at those small rpms
& generally relatively thin work pieces (1" or 2" thick? steel compared with 6" or 12" thick wood resawing?)

If you can make the wheel turn, it can be trued on the axle it runs on. Either with abrasives if you are good and have practiced before. :) Or by mounting a small cross-slide and tool bit somewhere that will access the wheel face, and oriented across. Then you have to decide whether to put crown in the metal, or make that true flat and dead co-axial. Then glue on the tire, and crown that.

Gearbox sounds like "find a replacement" for overall time and cost efficiency. Though of course you can make all the new gears & parts and rebuild it. The other details you need to show pix or we will all be guessing based on our own mental pictures.

smt
 

bobbyf

Plastic
Joined
Sep 29, 2022
Attached are a few pics of the wheel. The worst bearings are in two pillow blocks that hold one of the speed adjusting pulleys. A quick search showed at least some Browning PBs available so hopefully that'll be easy. My thought at the moment is to put a layer of epoxy in the low area then try to mount it back on the machine. If I can bolt some type of fixture to hold a file or sanding block I should be able to take off the extra epoxy and true it up. Then glue on new rubber and go. It's not as good as truing the wheel in a lathe but is it good enough?
Assuming I can get by that and figure out a way to remount the wheel, I'd still like to source a few tranny gears. I've seen pictures of delta saws that looked the same and wonder if DoAll didn't use the same transmission as well. Any thoughts on getting gears?
 

bobbyf

Plastic
Joined
Sep 29, 2022
Sorry - had to reduce the image sizes
 

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That is a good looking repair.

If I can bolt some type of fixture to hold a file or sanding block
that can be an exercise in frustration as either one will work, but load up almost instantly.

I should be able to take off the extra epoxy and true it up.
That can work, if you have a good epoxy and bond.

Then glue on new rubber and go.
Final truing and crown the rubber, and then go. :)

It's not as good as truing the wheel in a lathe but is it good enough?

You are wrong there, it can be better than truing in a lathe, so long as the wheel is accurately set up exactly the way it will always run. Full attention to solid mount, and good bearings. I don't know what that copper colored pipe in the bore is for? The issue with truing in a lathe is getting it centered exactly as it will run in the machine after you take it off the lathe. Though that, too, is possible.

So, the place to start is figure out how and what you are going to use to mount the wheel, and then effect that, solidly, repeatably (dead repeatable to put back on if it is removed at some point). Part of this comment involves a question: "Is the bore in the wheel true?" Can you identify a fitting method if it needs bored oversize to true it?

I don't know how far out of round the wheel really is. But if it is close, i would true the CI and forget about epoxy. I would (have done) using an angle grinder and prop to true large CI flat belt pulleys & including truing and crowning large bandsaw tires. You cannot just lay the grinder on and relax, though. You want it to only kiss off the high spots until it is round all over. That does take some practice and a good touch and support.

If you use epoxy, it will be necessary to fall back and use a guided system, say a small slide and tool bit. Because the different densities will cut or grind differently and the result would not likely be round with a free-hand approach.
I do true the rubber free hand with an angle grinder and support, and finish up with 60 or 80 grit belts on a backer block, by hand.

The wheel with probably be in balance well enough to cut metal.
If you use it for wood at high speed, it might need some attention to balancing.

I don't understand what the pillow blocks are fore?

Typical sources for gears, bearings and shaft fittings are Browning, Martin, and Boston Gear among others.

Are you aware of the Vintage resource for old publications?

smt
 
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bobbyf

Plastic
Joined
Sep 29, 2022
Stephen,
My best guess is that this was used somewhere that had a machine shop. The transmission case has been repaired and the final drive bearing replaced. It looks like they turned the wheel shaft and added a bushing. That's the copper colored pipe in the picture. I think the wheel turns true. I tested it on high speed once without a blade and didn't notice anything obvious. The bushing, bearing and case repair look like they were done right. What do you mean by CL? It sounds like your saying just glue on a tire and true that?? If I go that route can I do the truing while the wheel is on the saw? There shouldn't be a lot of pressure and a 3hp motor at less than 1:1 should have good torque....have I got what you're saying?
 
What do you mean by CL?

I wrote CI
= "Cast Iron"

It sounds like your saying just glue on a tire and true that??

No.
true the cast iron.

Then glue on the tire, and true and crown that.

If I go that route can I do the truing while the wheel is on the saw?
Yes. So long as the wheel is correctly and solidly mounted in good bearings, truing it on the saw is better than taking it off and doing in a lathe.

However, it should run pretty fast, to have good control with hand-dressing it. If the wheel turns slowly, the inclination is to lay the grinder on and follow the existing contour (bad).

If you can brace the angle grinder and delicately offer it to the wheel until it is going "tick-tick-tick-tick" rapidly as the wheel spins and you are only hitting the high spot, and be thoughtful and patient, it will true fairly rapidly. You will have to stop and check periodically that you are not tapering the face, and not crowning the face of the CI too much. A little bit does not hurt, but the edges should never be rounded.

Then glue on the tire, which will need re-trued after it dries, to eliminate high spots; and allow a slight, uniform crown to develop. Again, don't ever taper the wheel face if you want the bands to run true. You can use a heavy coarse section of 60 or 80 grit sanding belt backed up by a wooden block to do the final touch up.

There shouldn't be a lot of pressure and a 3hp motor at less than 1:1 should have good torque....have I got what you're saying?

Yes, so long as the wheel does spin close to woodsawing speeds.
Obviously, don't do anything dangerous, and don't do it if you have a voice in your head telling you not to.
Pay attention to where rags, cords, falling tools and objects, etc, etc might be likely to jump into the wheel and flail you mercilessly, or cause a wreck. Don't do it on this project if you are not fairly coordinated with some past practice in previous similar endeavors. Etc.

3 HP is strong enough to maim you for life.

The grinder support can simply be a work rest at a comfortable position, securely clamped, that would never let the tools tip into the wheel between it. (which would cause a wreck and possibly injury)

The tool position has to be trailing the wheel rotation, not against it, which could force a slip inward. either wrecking things or causing injury or both.

Oh, crap. I did stuff like this all the time but now feel i have to tell you to never try it.
There are actual risks with serious potential consequences.

Published accounts do include things like attaching routers to slides or swinging arrangements for truing and crowning rubber. That always seemed really dangerous to me.

Your sandpaper on a board will work, just very slowly. and be sure you are cutting off the high spots, not following the wheel.

again, don't do any of it if it feels dangerous.
Or if you can't see that you should feel that it is dangerous.....

smt
 

bobbyf

Plastic
Joined
Sep 29, 2022
SMT,
I understand your concerns. I'm 62 and been working with my hands since early teens. I have a lot of good stories but have managed to get through with all the pieces attached. I'm a lot slower and more deliberate these days.
I'm leaning toward a block or file just because there isn't much to remove and even a fine flap disk in the grinder could easily alter the face of the wheel. The only gotcha there is that I need the tranny to true the wheel. I haven't had much feedback on gears so I'm off to search the names you mentioned....Thanks!
 
Well i am glad to hear that you have attained mature years safely!

If you use power, don't use flat wheels nor any "conformable" abrasive.
You want a rigid surface.solid disc that only contacts the high spots as the wheel turns.
I have used a portable 4 x 24 belt sander with a hard platen on flat belt sheaves.
generally i have found the angle grinder easier on bandsaw tires.
It does require periodic checking, to verify the face of the wheel is co-axial.

smt
 
I also appreciate you posting on this forum, and don't intend to re-direct welcome traffic :)
However, another online resource where people obsess over Powermatic and Delta machines, and have repaired and rebuilt many examples is the home site of the vintage forum; OWWM. It's a lot more seriously and selectively moderated than this one. OTOH, that suits some people. And you can still pick & choose.

https://owwm.org/viewforum.php?f=77

On that site, there are a few more forums on woodworking, and on metalworking that will not appear unless you sign in as a member. If you post the question you posted here, there will be a 1/2 dozen people chime in, 8 of whom :) will have done various versions of similar repairs to the ones necessary on your saw & one or 2 might even know where OEM spare parts were last seen.

smt
 








 
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