Tough pulley removal - need suggestions

[Matt Day]

I’ve removed and pulled my fair share of pulleys over the years but I’m stumped on this one. The bandsaw is a 1980’s Vintage Centauro 600 CO, and to remove the motor the pulley needs to come off first.

Problem is, I can’t find a set screw that would lock the pulley to the key. I’ve looked everywhere about 6 times. Peeking on the motor side you. An see the shaft and the key/keyway. But no where is a hole for a setscrew, either on the inside part of the pulley or through the belt area. I tried pulling off the pulley with my big puller but didn’t want to force it and break something.

Any ideas? Just hit it with PB Blaster for a while and try to pull again?

[Tim Cardinal]

Bottom of the shive in line with the key?

[Matt Day]

Assuming you meant sheave, that’s the first place I checked.

[Peter Kuhlman]

Do you think it is a 2 piece sheave? From the pics you have very little room to work on that. Almost looks like it is a press fit one piece pulley. Sorry no right ideas for your dilemma!

[Allan Speers]

Heat it with a blowtorch?

[David Buchhauser]

Matt,

I would measure the outside diameter of the motor shaft on the side between the pulley and motor. Then compare this to the diameter of the round center portion of the pulley on the outside of the pulley (side away from motor) to see if they are the same. If this second dimension is larger, then perhaps that small round area (the one that has a small hole in it) is actually a removable cap that if removed might reveal some sort of bolt retaining the pulley onto the shaft. This would mean that the center of the motor shaft is drilled and tapped for a retaining bolt. This is only speculation and my best guess based on the photos. Also - the first photo showing the exploded view seems to show that the keyway does not extend all the way to the outer end of the motor shaft.

Otherwise - perhaps the pulley (sheave) is actually a press-fit onto the motor shaft and there is no retaining setscrew. As and aside: Early Chevrolet 283 (and some 327) engines simply used a press fit to retain the harmonic balancer/pulley to the nose of the crankshaft with a woodruff key to lock the balancer to the crankshaft nose rotationally. Later versions of the 327/350 engine added a retaining bolt. These versions had the center of the crankshaft nose drilled and tapped to accept the bolt. I know this because I have drilled and tapped some of the early crankshafts to accept a retaining bolt.

David

[David Buchhauser]

I would not recommend heating with a torch (unless you are not worried about damaging the motor). It would probably be best to apply penetrating oil ("PB blaster") for several days and then use your large gear puller (or a bearing puller) to remove it. It does look like the end of the motor shaft (if that is indeed what I am seeing in photo 2) has a small hole for centering the nose piece of a gear puller. So I guess now that I think about it - the presence of that small hole might indicate that the sheave/pulley is indeed pressed on.

[Matt Mattingley]

If you're absolutely sure that there is no grub screw! Spray it with WD-40 or (brake fluid) for a couple days, then put the torch to it. Many fitters use Loctite as a setting compound. Only heat will turn this to a Caramel sludge to reduce the hold. As well only adding heat to the sheave in a uniform fashion quickly Will allow the sheave to grow. a puller Will work great in these conditions. Many many motor rotor are assembled this way.

In some rare situations the key has a taper to it. Try to knock the key out a we bit before adding any heat. If the key is a taper fit there will be most definitely Loctite, and heat will be needed.

[Bill Dufour]

use a bearing splitter or you will bend the pulley. the diagram does not show a setscrew so I think it is a taper shaft press fit.
I would enlarge the opening to pull the motor with the pulley attached then look at it up on the bench. You can make a sheet metal shield later if needed to keep sawdust out.
Bill D.

[robert wiggins]

Too often the mechanic applies heat in close proximity to the shaft because that's where it's stuck. Big mistake because that also heats the shaft plus the sheave can't expand because the outer diameter is still cold. Attach the puller with a reasonable amount of torque then apply the heat to the outer periphery of the sheave allowing the heat to conduct to the center portion. With this method I've had 4ft. diameter bull wheels release heating with 2 rose bud torches for bout 20 minutes, while the portion contacting the shaft is still at a temperature we could comfortably touch.

[Paul F Franklin]

It almost looks like you could unfasten the motor and then lift it up and angle it to slide pulley out the opening while still attached. That would make it a lot easier to work on. Of course, your photos don't show the motor side so I don't know if there is clearance to do this.

[Bill Orbine]

Red stuff on the shaft behind pulley appears to be Loctite or some kind of adhesive? With no mechanical fastener on the pulley, perhaps the adhesive to "fasten" pulley was used . Use a puller set, preferably with a bearing separater tool behind the pulley. Is this pulley original to the machine?

[Richard Coers]

Red stuff on the shaft behind pulley appears to be Loctite or some kind of adhesive? With no mechanical fastener on the pulley, perhaps the adhesive to "fasten" pulley was used . Use a puller set, preferably with a bearing separater tool behind the pulley. Is this pulley original to the machine?
If red indicates Loctite, they put it everywhere. It's on the machine and the motor housing. A big puller and bearing splitter is the best option, but I bet it will take some heat as well.

[Matt Day]

It almost looks like you could unfasten the motor and then lift it up and angle it to slide pulley out the opening while still attached. That would make it a lot easier to work on. Of course, your photos don't show the motor side so I don't know if there is clearance to do this.


Paul you were right. I had to lift the motor and remove the motor mount, then tip the motor and barely got it out. So good news is the motor is out and I have easier access to work on the pulley.


I needed to get the motor off to lighten it but also for clearance down the steps and around a couple turns and into my shop. Saw is stripped to bear frame now.

Better pics are below. You can see that they’re definitely is not a set screw anywhere. Shaft measures 28mm. I will likely stop by the hardware store and pick up some MAPP gas and put some heat to the pulley, on the outer parts, not the shaft as has been pointed out.

[Paul F Franklin]

Good to hear. But if pulling the motor was the only reason you needed to get the pulley off, I'd leave that sucker on there......

[robert wiggins]

Agree, I see no appreciable wear to the pulley so I'd not open that can of worms by removing it unless you're working on a degree in industrial education.:D

Now that it's off you can determine if the shaft is tapered by 1) the difference in shaft diameters and also 2) if tapered I doubt the key will be parallel to the shaft.

[Peter Christensen]

I would stand the pulley and motor in a cake pan so the pulley can be submerged in ATF and Acetone (50/50) for a few days. The soaking should penetrate all nooks and crannies of the pulley, shaft end and key/keyway. Then try to remove it. You just need to be patient.

[Matt Day]

By ATF you mean Automatic Transmission Fluid?

I would like to remove it and clean out the motor and check bearings and such.

I still don’t know what that red stuff it but it’s everywhere.

[Peter Christensen]

Yes atuomatic transmision fliud.

[lee cox]

Soak in 50/50 ATF and acetone. Turn motor so pulley is flat, soak one side of the pulley shaft touching the pulley and then turn motor and soak the other side so the fluid is running down into the crevice of the pulley. You want gravity on your side. Soak maybe a day or 2 on each side.

[Allan Speers]

use a bearing splitter or you will bend the pulley. the diagram does not show a setscrew so I think it is a taper shaft press fit.
I would enlarge the opening to pull the motor with the pulley attached then look at it up on the bench. You can make a sheet metal shield later if needed to keep sawdust out.
Bill D.

Bill, I don't know if you're guess is correct or not, but I'm glad you posted this. I've never removed bearings before.
Did a little googling, and now I know what a bearing separator is.

It's also good to be aware that some pulleys might indeed be press-fit. I never knew that, either.

- Thanks!

[Carl Beckett]

I still don’t know what that red stuff it but it’s everywhere.

Sometimes the winding laquer spray is red. Sometimes they spray it on the windings before closing it up, just as another layer of protection. (Usually do this if I pull apart an old motor). Really shouldnt be on the shaft though (dont know if it could have been 'dipped'... doesnt seem likely but what do I know)

Loctite for the shaft would be more localized.

[Allan Speers]

If it was Loctite, wouldn't any sane person use the blue stuff?

[Peter Christensen]

"But I had the red and didn't want to go to town to buy something else."

[Matt Day]

You guys don’t understand, the red stuff is EVERYWHERE in the machine. I shop vac’ed about a gallon of the stuff out. This pictures is just part of what was picked into the back of the lower wheel (there’s a cavity from the belt sheave that’s on the back of the wheel) after I pulled it.

edit: you can see half of the tire that fell off too.

[Allan Speers]

^ Aliens have landed in West Lafayette!

That looks like something Mr. Spock would find on a distant planet.


Maybe some fool tried to use this saw to cut metal, and that's cutting fluid + metal dust that got all over the place?

[Matt Day]

Doubtful. My guess is it was whatever the company was cutting with it. Maybe sound insulation for inside the pianos or something. I briefly looked up how pianos are made and there’s some felt in there and some other felt-ish looking stuff.

I’m going to start soaking the pulley tonight.

[Mike Kees]

Matt ,when I took my motor in to get the bearings replaced I also could not figure out how to get the pulley off. They ended up pulling the motor apart and taking the shaft right out and then pressing it apart. It is the exact same pulley as on my saw.

[Matt Day]

Mike, so they got the pulley off the shaft with a bearing press or something?

[Mike Kees]

I think it was their large shop press. But yes they did get it off and replaced it as well. My pulley was flush with the end of the shaft when I took the motor in,now it is about 1/32'' out from flush. I was fine with that,motor has room to move on the mounting plate.

[Matt Mattingley]

I set Guide pins, gears, sprockets and plates... quite often. We call it an interference fit. We always freeze or heat. Any motors we use Loctite 620 and no freezing. Just a little bit of heat will reveal if Loctite is your culprit. As I said before, you will see this liquid candy pushing out of the fit if it is not interference. Sure, any hydraulic press will break this retaining compound. I’ve even driven pins in that have a 0.010 interference fit with a 800 ton press with no locking compound. It would probably need a 1600 ton press to remove this with new weld fit.
408630

[Matt Day]

If I do resort to heat, would MAPP gas be preferred over propane?

[Carl Beckett]

Doubtful. My guess is it was whatever the company was cutting with it. Maybe sound insulation for inside the pianos or something. I briefly looked up how pianos are made and there’s some felt in there and some other felt-ish looking stuff.

I’m going to start soaking the pulley tonight.

Agree it looks unrelated to how the pulley might be attached.

[Robert Engel]

On the pulley, with no grub screw, my guess is a tapered shaft/press fit.

[Bill Dufour]

Mapp gas ceased to be made around 2008. the current MAPP-pro gas only burns 100 degrees hotter then propane. I assume it has more heat then a propane flame. Waste of money for heating a pulley, if you have time to wait, a little longer for the temperature to go up. Probably safer to use propane, less chance of warping and cracking.
Bill D.

[Bill Dufour]

At yard sales I pick up twist lock electrical plugs,cheap. When I pull a difficult motor, like this bandsaw, I cut the cord and install a male/female twist lock on the motor supply. Any future motor work will be much easier and at a minimum I do not have to stand on my head to reconnect the motor wires.

[Matt Day]

Thanks Bill, for both tips.

[Matt Day]

Got it. Big puller and it came slowly with a decent amount of pressure. Thanks guys. Now to see what the motor looks like, guessing red!

[robert wiggins]

Pulley re-install will be interesting.:)

[Matt Day]

I’ll freeze the pulley which should help. I might do a light sanding of the shaft to take a thou or two off, and add a drill and tap for a set screw.

[Al Launier]

Glad to see you had success. Obviously I'm late with a suggestion, but what I've done in the past providing the motor casing is substantial enough behind the shaft & is sufficient to withstand the pressure is to use 3 bolt & nut combinations (making them up if needed) & install them between the sheave/pulley & motor. Unscrew the nut to apply a bit of pressure at a time while tapping as you go. Doing this slowly will pop the pulley. Although a wheel puller works well I've always feared breaking the outer diameter flange; the use of bolts would not. The downside with the use of bolts would be a motor casing that is not beefy enough to support the pressure of the bolts. Care is needed here.

[Al Launier]

I’ll freeze the pulley which should help. I might do a light sanding of the shaft to take a thou or two off, and add a drill and tap for a set screw.

You might also apply some anti-seize to the shaft once sanded.

[Andrew Seemann]

It would be heating the pulley for reassembly; it needs to be larger, same as for disassembly. I suppose you could dip the shaft in liquid nitrogen instead:)

If the motor has a standard shaft size, it might make more sense and be a lot easier to just find a regular set screw pulley from Graingers, McMaster, etc.

[Peter Christensen]

You would heat the pulley to mount it. If you cool it it shrinks and the hole gets tighter making it harder to put on. Put the pulley in the oven at 250ºF to 300ºF and it will probably slip on without the need for a press.

Andrew types faster than I do.

[Al Launier]

If you are looking to have a set screw are you able to drill & tap a threaded hole through the hub, even if at a slight angle, or, if there is enough wall thickness at the bottom of the pulley "V" drill/tap there but keep the head of the set screw below & lock with Blue Loctite.

[robert wiggins]

Please don't change to a set screw pulley. What you have works very well and will never screw up the ( expensive part ) the shaft. Set screwed pulleys are notorious for shafts needing replacement. If you make a pulley change at least go with an industrial standard, a split taper bushing sheave. To install or remove there is no heat, freezing or someone's macho hydraulic press needed, it's all accomplished with 3 little hex head cap screws.

[Matt Day]

Heat the pulley, yes, sorry. Like a bearing in the oven. In my head I think about how when water turns to ice it expands. I guess I can crank the heat up on the pulley a bit more than a bearing.

Robert- I’ve never seen a pulley with a set screw that tightens on the key be an issue. Are you thinking a set screw to the shaft? If so, then yes that’s a bad idea.

[robert wiggins]

I'm thinking both, keyed and screw to a shaft or screw to a flat on a shaft. With a set screw there is no interference fit as yours has. It isn't, if the set screw ever fails, it's when the set screw fails, and that's all too often and with negative results because that assembly is now loose on the shaft. By taking the set screw approach you are degrading a well built expensive piece of equipment to something we might see on imported equipment.

That split tapered bushing is nothing to sneeze at. Those are common to attach a 12 ft. dia. fan blade to a 2" shaft or a 2 ft. dia. 6 groove V pulley to a shaft.

[Brian Runau]

Metal to metal contact of components over time, with vibration, can introduce fretting corrosion. The metal components start to weld themselves together due to contact over time with the vibration. WD-40 and let it sit plus a little heat on the OD of the sheave might help.

[Matt Day]

Brian, the pulley is off already. See previous posts.

Robert - When I reinstall the pulley, I’m hoping that just heating the pulley will be enough to slip it back on without much trouble. If it doesn’t work, I will consider other options.

[Bill Dufour]

Glad to see you had success. Obviously I'm late with a suggestion, but what I've done in the past providing the motor casing is substantial enough behind the shaft & is sufficient to withstand the pressure is to use 3 bolt & nut combinations (making them up if needed) & install them between the sheave/pulley & motor. Unscrew the nut to apply a bit of pressure at a time while tapping as you go. Doing this slowly will pop the pulley. Although a wheel puller works well I've always feared breaking the outer diameter flange; the use of bolts would not. The downside with the use of bolts would be a motor casing that is not beefy enough to support the pressure of the bolts. Care is needed here.

If there is room, a bearing splitter can be used this way. They normally have two threaded holes parallel to the pulley shaft. Those can be used to pull or push.

[Bill Dufour]

Is the shaft tapered or straight?
Bill

[Matt Day]

Straight shaft.

And there was not enough room for my bearing splitter. The pulley is about 5 1/2 inches in diameter.

[Bill Dufour]

You can always replace the pulley with a taperlock one.
Bill D.

[Brice Rogers]

I thought that I'd throw out some numbers. When solid metals are heated they expand. For aluminum, it'll expand roughly 0.3% for every 100 degree F increase. So if you have a 1/2" shaft and heat it to 100 degrees above ambient or cool it below ambient, expect about a 1.5 thousandths change.

Steel and iron are roughly half of that.

From the pictures it looked like the pulley was steel/iron. So, if you heated it in a toaster oven (or if your wife isn't around, in your kitchen oven) to, say, 270 degrees F (a 200 F increase over ambient) your pulley (if steel/iron ID would increase by about 0.0015" (assuming the diameter is 1/2"). That should help a whole lot to put it back together. There should not be an issue of heating it higher - - say to 470 degrees F to achieve a 3 thou expansion. Some people think that when you heat a pulley that the ID gets smaller. It doesn't. It expands just like the rest of the pulley.

I suspect that you could probably heat the iron pulley up to 800 or 900 degrees F. without any issues. It is soft steel so you wouldn't be messing with its hardness. When the pulley reaches around 1500 F, it will be a nice orange color.

You'll want to wear good insulated gloves (no synthetics) and quickly and fluidly push it on in a single motion and then lightly tap it with a dead-blow or mallot. If you do it right, a single tap should do it. Then let it cool down and lock in place. You don't want to bang too much on the pulley because the forces are transferred to the motor bearings.

In theory you could also freeze the shaft with dry ice. I have had less luck doing that because it tends to frost up, and that has interfered with the quick positioning of the pulley. Doing both heating and freezing could also be done if necessary, I suppose.

[Matt Day]

Thanks for those figures Brice. So now I know I don’t need to heat it at 450 like I was thinking!

[Jerry Bruette]

If you have your mind set on reinstalling the sheave with a shrink fit don't polish the shaft with any type of abrasive cloth. Reducing the O.D. of the shaft or making it out of round in any way could affect how tight the fit will be.

If it were me I'd take Robert's advice and get a new sheave with either a Taperlok or QD bushing. They go on easy and at any location along the axis of the shaft. You'd be doing yourself and any future owner a big favor.

[Matt Day]

You’re right about not removing any material off the shaft. But I’m not going to spend what $30-$50 on a bushing and new sheave for the next guy.

[Allan Speers]

Please don't change to a set screw pulley. What you have works very well and will never screw up the ( expensive part ) the shaft. Set screwed pulleys are notorious for shafts needing replacement. If you make a pulley change at least go with an industrial standard, a split taper bushing sheave. To install or remove there is no heat, freezing or someone's macho hydraulic press needed, it's all accomplished with 3 little hex head cap screws.


These are aso better because they keep the pulley centered, thus better balanced.

[Erik Loza]

Matt, I tried to reply to your pm about the bandsaw but your mailbox is full.

Erik

[Thomas McCurnin]

Quick Internet Research--Reflected that other models of that same bandsaw did not have any set screw holding that main drive pully onto to the shaft. See, for example
http://www.targetmanufacturing.co.uk/wp-content/uploads/Centauro-CO600-700-800-900-Bandsaw-Manual-Parts-List.pdf

I suspect it is press fit

[Matt Day]

It was press fit. Pulley is off.

Appears the motor fan is too, but much less to grab onto and a lot more brittle.

[Matt Day]

Anybody have any idea what kind of puller would fit here to pull the fan?

[Paul F Franklin]

It looks like a regular two jaw puller would work, but if the holes in the fan are too small for the puller arms, then search for "thin two jaw puller" for many options with thin arms. You're going to be well equipped for pulling stuff by the time this job is done!

[Peter Christensen]

That's a nice cast fan and probably not very strong. I would snake a wire between too adjacent holes and form them into a loop that I could get a slide hammer on. Then I would take a hot air gun and heat the fins at the base around the shaft and when hot pull it off with the slide hammer. Wrapping some kitchen foil around the outside of the fan's fins will help to contain the heat. I'd worry the gear puller would break the fan if used on the outside.