Worn keyway

Looks like the key rolled. How badly mangled is the hub?

it's a14 in. fiberglass fan the keyway on the fan seems to be in good condition

it's a14 in. fiberglass fan the keyway on the fan seems to be in good condition

This motor seems small enough that it may just be cheaper to replace it than to fix it.

Richard W.

Brand new motor is over $200 how much could it cost to have a new keyway cut on the other side of the shaft

I'm not aware of anything special about your partiular motors, but new surplus motors typically sell for about $20-$40 from surplus sellers.

It might be worthwhile to look at few surplus sources, such as the Surplus Center, or various other sources.

You may need to drill a couple of mounting holes or shim the mount a little for a different style of case, but a new motor is good insurance for your business profits. You might even be able to find new surplus blower wheels for your dryers that have set screws for mounting instead of the threaded shaft of the original equipment motors.

If you have a good motor repair shop nearby, they may have some used rotors with threaded shaft ends, but I wouldn't consider it to be very likely.

Fractional-horsepower motors are cheap. When bought new, you can reasonably expect that the centrifugal switch, a capacitor or a bearing isn't going to fail in a month.

That shaft in the picture is mangled to the extent of being scrap. To be repaired correctly it should have the shaft built up to full diameter with weld, turned on lathe, then have a new keyway cut in it. It's unlikely that any epoxy or makeshift fix will be permanent.

I wouldn't know if this is a common problem with your dryers, but you'd be wise to routinely check each machine. Keys with set screws would be more secure for this application, but not if the screw threads would be in the fiberglas material. If there is a steel, aluminum or brass hub molded into the fiberglas fan, drilling and tapping an accurate hole over the keyway should ensure that the key doesn't start wallowing out the keyway on the shaft.

Can you attach one of the flanged or face-mount collars in the middle of this page to the fan and not bother with the key?

Brand new motor is over $200 how much could it cost to have a new keyway cut on the other side of the shaft

I got the impression you didn't have the equipment to do it, or why would you ask if it could be done with a file.

Richard W.

If you go shopping around for quotes I suggest taking one motor and fan with you.

I went to the surplus site and I see how with a little modification I could get a motor much cheaper. The other type dryer motors that i have one of which burned out and cost me over three hundred has approx. a 14 in. shaft with a thread on the end what would I do about that.

That looks like just what I need. Do I understand this, the collar locks to the shaft then I would attach the collar to fan drilling holes and using screws or even bolts. I had actually thought of trying to drill a hole through the nut to help secure it but this looks perfect. Thanks Martin

key?

>

You've got it. Since you're relying on friction between the shaft and collar to transmit torque, make sure there's no oil or grease on the shaft and ID of the collar. Grease the collar's clamping screw to maximize gripping force. If it's more convenient you can modify standard collars by drilling them yourself.

Good idea, Ned. The slot could be filed to take the key, since its slot extends through the threads.

The Surplus Center is only one of hundreds of surplus sellers in the U.S. I've seen quite a few appliance fractional HP motors with extended shafts over the years (longer than the motor case), like you mentioned, but I don't recall where.

An alternative for the long motor shaft might be a modification of the dryer housing if you can mount separate shaft between a couple of bearings. Then an ordinary motor with a shaft coupler might eliminate the need for the special motor.

The shaft collar solution Ned mentioned should work well for a blower/fan wheel load, as far as gripping the shaft and having a secure connection to the blower wheel.

You will want to get the collar aligned correctly to the shaft centerline (almost perfectly perpendicular) so you don't inadvertently introduce any wobble in the blower wheel. A continuous vibration/shaking in the wheel will likely break out the fiberglas around the screws that attach the wheel to the collar.

Without being able to see the actual machines, and not knowing what tools and skills you have to work with, makes speculating what repairs could/can possibly be done, mostly guesswork from a distant position.. but many motor applications can be implemented in various ways to do a particular task. With the addition of a couple of parts, or some modifiations, it's possible that one inexpensive motor could be used in different machines.

The down side of obtaining new surplus parts is, that they are often in limited supply, so if you find a particular part that is especially useful, get a supply of them.

FWIW, in this economic slump (or other preferred term), your public facilities may be more in demand, so having equipment in good operating condition is likely to keep happy customers returning to your business.

Any suggestions as to the best way to make sure the collar is correctly aligned.

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My suspicion also. If the key rolled it had to carve a passage through the fiberglass although it might not be visible externally.

Possibly a spacer bushing drilled lengthwise for the axial collar screws would allow the fan and collar to both be located where they work best. The drive torque would pass through the screws as shear at the junctions, so they ought to be hardened socket head cap screws.

The spacer could be a square block of scrap aluminum of the right thickness with a centered hole drilled for the shaft.

it seams as if a big part of the problem is that while the metal bushing inside the fiberglass fan is 1 7/8 in. the key used was 1 1/4 in.. I recently repaired one with this problem by cutting a key as long as possible and putting a tooth washer on each side to give the nut that holds it on more grip. It is still to soon to know if this worked long term or not. I always have one spare motor setup on hand so I can make a quick switch. Upon closer inspection of the fan the key way inside has some damage but not as bad as the motor shaft. I thought I could attach the collar to the fan by drilling holes through the fiberglass of the fan. I now see that the fiberglass at that point isn't thick enough and would surely break at the bolt holes. The collar would need to be attached directly to the metal bushing. My thought at this point is that by using a combination of whats left of the original key way, longer key and the bushing it will do. the loctite scares me because if i ever want to remove the fan to do the motor bushing I worry the fan won't come off.

Should read longer key and collar it will do

I've generally always gotten some level of enjoyment out of repairing stuff just for my own use, but for a commercial application that a man derives income from, replacing the motor would very likely be the most cost effective solution.

The objective as I see it would be to get the machine back in operating condition so it can be earning money, and not fail again within a short period of time (putting the guy back at square one).

Anything can be repaired, and this example is no exception. The OP said four machines have this problem (or four more of 'em), so the cost of replacement motors, although significant, will eventually be recovered, and the cost is closer to couple hundred instead of almost a thousand (at over $200 per motor).

The new motors will probably run reliably for quite some time. When repairing the old motors, they're still just used motors with lots of hours on them.

The mangled motor shafts could be repaired fairly quickly and effortlessly with the right equipment, and the mounting interface between the shaft and blower wheel could be upgraded/improved, or maybe better-made blower wheels could be sourced.

As many of the HSMs here know, having a couple of metalworking machines makes a great many things possible, and often practical.. but we can also remember when we didn't have the machining capabilities, and generally everything was much more difficult (and many times just beyond the scope of our capabilities with only limited tools).

Working with just a hacksaw, file, drill and/or a Dremel or die grinder can sometimes produce satisfactory results, although progress may be slow. Relying on epoxies and other band-aid "miracle" products can often be (should be)last ditch efforts because there might not be a second chance after trying those products.

Maybe it's mostly age, but I never liked to see someone bust their ass to attain poor results, yet that's what some folks are used to doing. Many large companies operate like this year after year.

I've looked at some repair jobs as an opportunity to improve the assembly or machine, to make it a little better than it was (what led to the failure/wear), or at least easier to repair the next time if the original design just demanded periodic repairs.

These methods continue to get more difficult to implement as products are made more cheaply, essentially throw-way products, and more frequently finding new products to be faulty as soon as they're taken out of the box. I'm beginning to dread needing to buy anything new.