AO Smith Motor Shaft End Nut

[Duckman]

I bought 1954 Greenie for $35. It basically amounted to a couple of boxes of parts. I am in the process of pulling it together to use as a sanding station. Pressed on some new bearings for the headstock and rebuilt the motor. This is the original motor (A.O. Smith) with the nut holding on the spring and sheaves. The nut is missing. The washer is missing too. I have the key, spring and sheaves. I tried a couple of different nuts at Ace Hardware. None worked. Anyone know what the size and thread type is? Is it a proprietary thread? Is it reverse threaded? Where can I get it?

[JPG]

IIRC it is a left hand thread.

[Duckman]

My cheap HF digital caliper indicates it is 1/2 inch. I will go onto granger and see if I can get a couple of reverse/left thread nuts of different thread types and see if one will screw on. I have to believe it would be something fairly standard. I may see if I can get a new washer from the mother ship and see if that will work. Unless someone has a better suggestion? I

[DLB]

My cheap HF digital caliper indicates it is 1/2 inch. I will go onto granger and see if I can get a couple of reverse/left thread nuts of different thread types and see if one will screw on. I have to believe it would be something fairly standard. I may see if I can get a new washer from the mother ship and see if that will work. Unless someone has a better suggestion? I

More of a question than a suggestion. A new washer from the MS will be 5/8" ID. On the original motor, was the washer meant to be on the 1/2" or 5/8" part of the motor shaft? Maybe Granger has something like this too and you'd only get hit for one shipping charge.

- David

[Duckman]

Honestly, no clue whether the washer should be 1/2 or 5/8 on this. I have a headstock from the 80s I am working on, I will check it out and compare. Suspect a washer with 1/2 inch ID will be the way to go. I will check out granger. Also I am going to count the threads to see if I can get an idea of whether to go with 1/2 13 or 20 in a lefthand/reverse thread at Granger. I will check Fastenal too.

[Duckman]

I bought some 1/2 inch 20 thread per inch, reverse/left threaded nuts online. Had to buy 8 for about 5 bucks, 10 with shipping. It worked. Now what to do with half a dozen nuts I have no use for.

[jsburger]

Next time someone on the forum needs one you can send them one.

[chapmanruss]

Duckman,

Looks like you found a good solution for the missing nut. The original nut (part A2802) was a special one and did not use a washer. In the parts diagram section shown below is the nut with the hex part only on the outside end of the nut while the inside end is round for the spring to go over. This was the same for both 1954 manuals.

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1954 Motor Shaft Nut.jpg (164.77 KiB) Viewed 538 times

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Your $15 nut plus a washer was probably a lot cheaper than getting an original nut if you could find one.

[Duckman]

The picture is really helpful. I could never find an owner's manual going back to when the motor shaft spring was held in with a nut versus a retaining ring and washer. I am pretty sure they went to the retaining ring by 57 or 58 at the latest. I did not realize the original nut was big enough to hold on the spring without a washer. I ran across some pictures that made it look like the nut or retaining ring was on top of a metal shot glass that covered the spring. I have never seen that "cup" for sale on ebay or anywhere else. I suspect it was only done a short production run. My plan is to use a washer with a 1/2" interior diameter. Not ideal or original but it should work. Might put on a dab of locktite although it should not be necessary with the reverse thread.

[Duckman]

Mr. Russ: A question. Most pictures and videos I have watched of early motors shows the capacitor mounted on the back of the motor, sort of over the centrifugal switch "box". But this motor has no provision made for mounting on the back. However, there were two holes drilled and tapped in the motor casing (appear factory made, not dyi) and the wires for the capacitor come out near those threaded holes. It looks like the capacitor mounts on the side of the motor inside a housing, similar to motors today. My plan is to design a 3d print a capacitor housing that will fit the capacitor and be mounted to the side of the motor using those two holes. What does the old owner's manual you have show in terms of the capacitor mounting?