opening sheaves

[operator]

Whats the easiest way you guys have found to open adjustable sheaves?

How do strap wrenches work?
Need to open one on a liebert unit.

[airworx]

loosen allen screw take a couple of pipe wrenches and break loose then adjust.

[Islander]

loosen allen screw..find it won't move..spray with wd 40..give a couple raps with pliers or something heavier..not on any edge..try hard by hand..if it will budge at all you got it..just keep working it back and forth.

if it did'nt budge by hand go get the pipe wrenches.

have not tried a strap wrench.

[tab-tech]

........ WD-40 is not really a very good penatrating fluid.
I use PB Blaster from the car parts store (it eats the rust away). Try it once and you'll be sold on it. :)

[duct_dude]

I use two spanner wrenches with the 3/16" pin. you remove the set screw and put the wrench on there and they work great.

[rubobornot]

pull it off and replace it with a fixed sheave that puts the OD the same , less wear and vibration. If you look at the start up instructions on most AHU's the var. pitch sheaves are for start up only and should be replaced once the blower has been set up. Very seldom does it ever happen.

[sirtab]

Originally posted by tab-tech
........ WD-40 is not really a very good penatrating fluid.
I use PB Blaster from the car parts store (it eats the rust away). Try it once and you'll be sold on it. :)
Have you ever tried BrakeKleen I put it on a shaft and fell on my ass when I went to yank the pulley off it worked so good, and it was a pretty crusty shaft and pulley, been using it ever since.
If 2 pipe wrenches don't work stick it in a vise and try.
But if it's got that many crustys it's probably ran at that pitch for quite a while, changing pitch after the pulleys worn that much will probably cause belt slippage.
Most VP pulleys are fairly cheap anyway.
I will try PB Blaster though.

[Islander]

rodger on the pbblaster and brakekleen will have to give it a try.

[seaboard]

The PB Blaster works great and is available at more places now. Aerokroil works well also. With pulleys and fan blades, weigh the cost of the labor to remove the part vs. the part (marked up). In many cases, it's not worth the labor especially if you waste an hour and have to buy one anyway. Small adjustable motor sheaves should be replaced every few years (depends on the run time). If you look down into a motor sheave and you can see paint worn off above the belt, the pulley is worn. You can feel it with your finger. You may be tempted to close the pulley and thereby raise the belt back up to a clean surface but you shouldn't do that. As the pulley wears again, the belt will slip into the old groove and get wedged. I've seen many bearing and motor brackets ripped apart by someone doing this or by opening the sheave too far (past the veed surface). Norm has an excellent article on another thread that shows the math behind air flow in relation to motor pulleys. You can use those formulas to determine exactly how many RPM's the worn pulley is robbing from you. My compressor rebuilder believes worn motor pulleys is the #1 killer of compressors.