Unisaw Arbor Nut Issue

[Dimitrios Fradelakis]

I have been putting off on starting this thread but unfortunately I have run out of options. I have a right tilt Unisaw and I have a extremely hard time getting the arbor nut on and off when it's almost off the arbor. When putting the nut on It will thread in almost all the way and then it stops. Sane thing happens when I'm taking it off it will come off 90% of thruway and then stop. To remove it I have to take a pair of vise grips and clamp down on the washer to the right of the blade to keep the arbor from spinning to remove it. The same fiasco applies to when I need to install the nut. I have tried grinding down the end of the arbor and nothing. I have tried filing it and that doesn't help either. Does anyone have another solution to fix this problem? The arbor nut will sit close to completely flush with the end of the arbor and stop turning. It has caused me to not want to work in the shop because when it comes time to swap blades or put my dado set on its a long drawn out process.

[Bob Vavricka]

From your description, I suspect the threads on the arbor are damaged at the point where it is hard to get off. I would think if the nut was damaged that it would be hard to turn all the way. Can you see any nicks or damage to the threads at the location where it binds up? I believe that is a left hand thread, but I don't know what size/threads per inch. If it was right hand, I would suggest getting a thread die the size of your arbor and see if it will straighten out the threads. I don't know if a left hand die will be readily available. Besides damaged threads, the only other thought is a bent arbor, but that would seem unlikely.

[John Piwaron]

I would suggest getting a thread die the size of your arbor and see if it will straighten out the threads. I don't know if a left hand die will be readily available.

Not only that, but the threads on my Unisaw arbor look like Acme threads. I was about to say I'd never seen a die like that, but thought to open my McMaster-Carr catalog. Sure enough, on page 2561 of catalog 118, they offer several different sizes. Maybe one of them will work. They have a 5/8 - 8 and a 5/8 - 10 thread size. They don't say if they're right hand or left hand. Each of them cost $67.62 Not cheap, but cheap enough to save an expensive saw. And probably cheaper than a new arbor.

[Don Huffer]

I have the same saw. While I haven't had any problems as you mentioned. The threads are in fact acme left hand.

At the point of difficulty when the nut stops. that is where your problem is. Sounds like its not on the end. I would get a bright light and carefully look the threads over. Acme threads can be roughed up pretty good before they jamb. I thin file will probably be all you need.

Don

[Rich Enders]

Sounds like the arbor threads, and they need to be chased which is an industry word for cleaned up. However the arbor is probably hardened steel so the clean up may not be so easy.

Can you light up and magnify the arbor, or photo or video it and then blow up the photo or video? To solve the problem I think you need to clearly see what is causing the problem. To confirm that it is the arbor rather than the nut, screw the nut on facing one way, and then reverse it and screw it on again. If the arbor is the problem, then you will not experience a difference whichever way the nut is applied.

A die may not be able to cut the hardened steel, and since you are not trying to cut new threads, a grinder may be all you need to clean up the existing threads. Even a metal file might work.

[Dimitrios Fradelakis]

I took my Dremel to it with a grinding wheel and cleaned up the end of The arbor the best I could. For god measure I turned the saw on (blade removed of course) and ran a wire brush from side to side to clean up any grime between the threads. Put the original nut back on and it went on with no issues! Don't know whch one of the two did the trick but I'm just happy its fixed. Thank you to everyone who responded to this thread!

[John Piwaron]

It's fixed! Yay!