Loctite on Sheldon hub?

[Mike Weaver]

This is taken from the following thread:
http://www.sawmillcreek.org/showthread.php?t=14439&highlight=sheldon


Here are some instructions that I used.

If you are installing the normal counter-clockwise-rotation (as viewed from the blade side of the blower wheel) 14" impeller from Sheldon’s Engineering on a motor that has a 7/8" shaft, normally no instructions are provided with the
wheel. The following procedure is provided to assist you in getting a proper installation.
1. Remove the three screws that hold the QD-style split, tapered bushing in the hub that is welded to the center of
the blower wheel’s backplate, then remove the bushing.
2. Take one of the screws, and insert it, one at a time, into each of the threaded holes in the split, tapered bushing, and verify that it can be screwed all the way through the hole with no significant resistance due to paint or other interference. If the screw does not go smoothly through all three threaded holes, use a matching tap to chase the threads and clean out any paint or debris before continuing with the assembly. Failure to perform this step will result in incorrect torque values when tightening the impeller onto the bushing later in the procedure. When finished, remove the screw and place it with the other two.
3. Place a 3/16" square key at least 1 inch long (usually supplied with the motor) in the keyway on the motor shaft, then slide the key toward the motor body until it cannot be moved any farther while still fully down in the
keyway slot. Align the split, tapered bushing with the key, then slide it onto the shaft with its big end toward the motor. Position it so that the face of the large end is flush with the end of the key, then verify that the key
cannot be moved any farther toward the motor — that it is all the way to the end of the slot. Use an Allen wrench to fully tighten the setscrew in the QD split bushing so that it engages the key and holds it firmly in position.
4. Before placing the impeller on the hub, use a clean, dry cloth to wipe the outside of the tapered part of the bushing and the interior of the hub on the impeller to make sure there is no debris or other contamination that
could interfere with the proper seating of the hub over the bushing.
5. Align the unthreaded holes in the impeller hub so that they match the corresponding threaded holes in the split bushing on the motor shaft, then gently slide the impeller onto the split bushing. Insert the three bolts supplied
with the impeller into the three unthreaded holes in the hub, then screw them into the matching threaded holes in the split bushing. Screw them in until the heads of the three screws rest against the hub and the impeller is lightly seated around the split bushing.
6. Carefully tighten the three screws a bit more so that the bushing will not slide on the motor shaft, then carefully rotate the impeller as you observe it from the side. Watch the distance between wheel and the motor mounting
plate to make sure there is no wobble. There should be very little wobble, if any at all, other than normal distortion in the metal from welding.
7. If the impeller is running true with no wobble, tighten one of the screws until the torque required to turn the screw reaches 6 foot-pounds (72 inch-pounds). Repeat for the other two screws, tightening each one to 6 footpounds. Repeat, one more time: tighten all three screws again to 6 foot-pounds, but do not tighten any more once the torque is reached a second time. Do not oil or lubricate the screws in any way before installing them. Torque specifications are for clean, dry screws only. The spacing between the blower wheel backplate and the motor mounting plate should be about 1/2" to 3/4", but may be more, depending on the length of the slot and length of the shaft on the motor.
Impeller removal:
Should you ever need to remove the impeller, remove the three screws, insert them into the threaded holes in the hub that is welded to the blower wheel, then use them as pushers to force the hub away from the split bushing holding it to the shaft. Remove the blower wheel from the split bushing, loosen the set screw holding the key, then slide the bushing off of the shaft.


Hope this helps.


Has anyone used loctite on the screw threads? I think I'd like to use the Blue Medium strength stuff, but am curious about the resulting torque needed (bare screw needs 72 in-lbs)

Thoughts?

Thanks folks!
-Mike

PS my filter stack is built, for better or worse....

[Jim O'Dell]

I don't know the answer to this particular question, but have heard not to use any type of anti-sieze material as this will void the warranty. If no one has a definitive answer on this, I bet a call to Sheldon, or go to their web site, there might be way to email them with the question. i think they would be the best source. I have thought about the same thing myself as I am in the process of assembling my Clear Vue cyclone with their new impeller, and it appears to be very similar to the Sheldon you have and Clear Vue used to use.
What cyclone do you have? Jim

[Ken Garlock]

Hi Mike, when I assembled my Sheldon/Echoles blower I did not use anything other than a wrench. The fan is pretty well balanced, so I don't think vibration is an issue, YMMV.

The Sheldon people usually respond to Emails in a day, two at most. Give them a shout for the expert opinion.

[Mike Weaver]

I don't know the answer to this particular question, but have heard not to use any type of anti-sieze material as this will void the warranty. If no one has a definitive answer on this, I bet a call to Sheldon, or go to their web site, there might be way to email them with the question. i think they would be the best source. I have thought about the same thing myself as I am in the process of assembling my Clear Vue cyclone with their new impeller, and it appears to be very similar to the Sheldon you have and Clear Vue used to use.
What cyclone do you have? Jim

Jim,
I have a Pentz built cclone. He actually produced a few complete units and I was one of the lucky few.

I've posted a few updates, but no pics yet.

Thanks,
-Mike

[Mike Weaver]

Hi Mike, when I assembled my Sheldon/Echoles blower I did not use anything other than a wrench. The fan is pretty well balanced, so I don't think vibration is an issue, YMMV.

The Sheldon people usually respond to Emails in a day, two at most. Give them a shout for the expert opinion.

Ken,
Thanks. I'll drop them an email and report the findings in case anyone else is interested.
Thanks,
-Mike

[Jim O'Dell]

Mike, please do post the findings. I for one would be interested, even though mine is not a Sheldon unit. Thanks! Jim.

[Greg Mann]

Mike,

The tapered bushing and hub create a mechanically wedged lock, similar to that of a router collet, but with more mechanical advantage. You could probably remove the screws after they have been torqued to spec., and, without any unusual vibration present, the hub wouldn't come loose. But I wouldn't recommend it. There is no real stress on those screws except the 6 foot pounds, which is all it takes to create the mechanical advantage. While I think Loctite is great stuff, this is probably not a good place to use it. If you ever did need to take it apart the residual Loctite in the holes could sabotage your subsequent tightening procedure.

Greg

[Mike Weaver]

Mike,

...While I think Loctite is great stuff, this is probably not a good place to use it. If you ever did need to take it apart the residual Loctite in the holes could sabotage your subsequent tightening procedure.

Greg

Greg,
That's why this forum is great...you guys think of everything!
I hadn't thought of that either.

Cheers,
-Mike
PS I did contact Sheldon's to be complete & will post their comments should I get any.

[Leo Hill]

First caveat - I only spent 22+ years in heavy industry as a millwright and in that time I did not deal specifically with dust blowers... But...

I've worked on taper-loc™ bushings and hubs nearly every day of those 22 years.

IME, hubs this small usually use 1/4-20 bolts and do not need to be over-tightened. We usually (almost) never used anything beyond the torque that a 7/16" wrench would provide. We (almost) always used a split lock washer and the Taper-Loc™ was tight enough when the washer was fully compressed. Never used a torque wrench so I don't know how much beyond the torque specs quoted above we went.

But I do know that too much torque on the bolts does contribute to the hub spliting - usually at the key way. But this is also more prevelent on the hubs without flanges - but not unknown on the flanged hubs.

As for lube, never-seize or loc-tite. Nope. Nada. Zero. Zilch. As Greg Mann mentioned, there is no need for "enhancements" as the geometry of the hub and bushing create a self-locking (as in together) whole. Much the same way that a drill taper remains in the quill of a drill press and transmits the torque of the motor through the drill bit and drills into metal.

So I would suggest nothing more than a lock-washer under the bolt head and since torque spec's are provided, use them. No torque wrench? Then nicely snug using the appropriate sized wrench will most likely be good-e-nuff.

Best,

Leo in San Antonio

[Mike Weaver]

First caveat - I only spent 22+ years in heavy industry as a millwright and in that time I did not deal specifically with dust blowers... But...

I've worked on taper-loc™ bushings and hubs nearly every day of those 22 years.

Uh, that's WAY more experience than I have,so no caveat needed IMHO...



IME, hubs this small usually use 1/4-20 bolts and do not need to be over-tightened. We usually (almost) never used anything beyond the torque that a 7/16" wrench would provide. We (almost) always used a split lock washer and the Taper-Loc™ was tight enough when the washer was fully compressed. Never used a torque wrench so I don't know how much beyond the torque specs quoted above we went.

But I do know that too much torque on the bolts does contribute to the hub spliting - usually at the key way. But this is also more prevelent on the hubs without flanges - but not unknown on the flanged hubs.

As for lube, never-seize or loc-tite. Nope. Nada. Zero. Zilch. As Greg Mann mentioned, there is no need for "enhancements" as the geometry of the hub and bushing create a self-locking (as in together) whole. Much the same way that a drill taper remains in the quill of a drill press and transmits the torque of the motor through the drill bit and drills into metal.

So I would suggest nothing more than a lock-washer under the bolt head and since torque spec's are provided, use them. No torque wrench? Then nicely snug using the appropriate sized wrench will most likely be good-e-nuff.

Best,

Leo in San Antonio

Leo.
Thanks for the information and I don't think I need to get Sheldon's input to proceed.... No loctite for my hub - the expert has spoken and I'm listening. :D

I will still post Sheldon's comments for those interested when I get them.

Thanks again Leo,
-Mike