Question re shaper spindle rotation

[Doug Herzberg]

I inherited a 1/2" Craftsman shaper from my dad's shop. Generally, I use a router table, but occasionally, like today, I find a cutter in his collection I can't match with my router bits.

The shaft has a right hand thread and the spindle rotates clockwise when you look down on it from the top, so the natural tendency of the inertia of the nut holding down the cutter and the rotational force of the shaft is to loosen the nut, which would allow the cutter to ride up, possibly in the middle of a cut. Is this right?

It is possible my dad replace the motor without checking the rotation. Should I change it?

[Doug Herzberg]

I think I answered my own question. I found an owner's manual online at http://www.managemylife.com/mmh/lis_pdf/OWNM/1110341L.pdf. It says the motor shaft should rotate counterclockwise. Further down, it talks about reversing the rotation in order to use a cutter upside down, but that leads to the problem I discovered.

[Rick Lizek]

Use a double nut and you won't have any problem with the cutter coming off. Standard procedure with this operation.

[Mark Wooden]

Your machine has a slot milled into the spindle threads. There should be a hardened keyed washer that goes under the nut that will stop the nut from loosening when running clock wise. They often get lost and are hard to find these days, but sometimes found on the auction sites. Also, your spindle nut is probably an Acme thread, and the nuts are a not so common hardware item any more, but available.

If the keyed washer ( #6 in "Getting to know your shaper") is lost, you can use a 1/2" stop collar with a setscrew. The set screw should be ground flat on the end, and if necessary, on the sides, so it fits the slot well. Use permanent Locktite to hold it in place in the collar. Use it with all shaper set ups.

I've found that double nuts can still slip. Usually there's double nuts because someone lost the keyed washer.

[Doug Herzberg]

Thanks. I have keyed washers top and bottom, and they are helping. Just finished a day running clockwise without any mishaps. The nut came loose once, but I caught it before any harm was done.

[Mel Fulks]

I've used machines that only had the keyed washers ,no extra nut , and that worked fine. I'm surprised that it started loosening even once.

[Mark Wooden]

As with Mel, I've never had a keyed washer let the nut slip. Was the tab of the washer under the nut engaged in the slot? Can the motor you have be re-wired to turn CCW?

[Peter Quinn]

I to inherited a craftsman 1/2" shaper from my father, has the keyed washer, I replace the original anemic emerson motor with a grizzly TEFC, bit more power, specifically added a reversing switch to match the original. Runs fine in reverse, tighten the nut sufficiently to keep things held down. Ive run much bigger shapers with much bigger cutter heads in reverse, all run fine with the lock washer involved. Fairly secure concept. Good luck with it. I use mine as a coping machine.