Tough pulley removal - need suggestions

[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