Pm 66 arbor shaft threads complaint

[Bernie Kopfer]

Whenever I mount a full (3/4") dado set on my saw the arbor nut only goes on about half way. Apparently one time I overtightened the nut and distorted the threads slightly on the arbor shaft because now the nut no longer spins freely but I must use the wrenches to screw it on. Can almost do it with my fingers but not quite. Examination of the arbor threads looks like they are slightly "distressed". Mostly annoying!! Might buy a new nut and see if it helps. The RH arbor flange washer appears to be fixed on the shaft and I use the identical PM flange washer against the dado set for even pressure on the left. Am I missing something or does PM not intend the 66 to take full dado set?

[William Hodge]

There's not enough room for the flange and a thicker dado set. The choice is threads under the nut, or a flange and the nut hanging off. I just skip the flange when there aren't enough threads for the not to be all the way on the shaft.

Hanging the nut off with distorted threads doesn't sound like a good idea. I have always wondered what happens when the nut falls off when using a dado set.

[Bill Dufour]

They make thread files for acme and buttress threads as well as the standard 60 and 55 degree pointed ones.
Bil lD

[Lee Schierer]

When I use my adjustable dado I don't use the outside flange washer. I then have enough threads to properly secure the dado with the nut.

[Paul F Franklin]

If the nut is only sticky at the end of the arbor, and turns freely further down the shaft, then the arbor threads are damaged. If the nut is tight the whole length of the arbor, then it is likely the nut that is damaged.

If it's the nut, then replacing it is probably the cheapest way to go.

If it's the arbor, you can buy a rethreading die of the appropriate size; they are designed to repair slightly damaged threads. They cost a bit, but cheaper than replacing the arbor if the threads become too damaged. McMaster is one source.

You can get rethreading taps as well, but it would probably cost more than than a new nut.

As others have said, you are better off leaving off the flange washer and fully engaging the nut.

[Frank Pratt]

Leaving the outer washer off is standard operating procedure when using all the chippers.

[Bernie Kopfer]

Thanks for the help, will leave the flange washer off from now on. As I said the arbor threads are minimally damaged and i can live live with it., getting a new nut will help a little.

[Alex Zeller]

If it's just a small segment of the arbor you can use a small file to clean up the threads. It's easier to see when the threads are damaged from something hitting them but even if it's slightly stretched out you can fix them.