Tablesaw arbor nut comes loose - and I now know why

[Travis Porter]

Re: Tablesaw arbor nut comes loose

Roy, it is occassional as you suggest, but it has been frequent enough and I used the saw enough this past week with the standard insert that I would have thought it would have reoccurred.

Bruce's suggestion to shift the belts makes sense. I will do that tonight and go back to the ZCI and see what happens.

Pete, I have tried "recutting" the ZCI twice to make sure it isn't the culprit. It made no difference. I do hear the ZCI dragging some as it is a commercial one with a formica face, still, it seems wierd for the nut to come loose.

 

[Toddler]

Re: Tablesaw arbor nut comes loose

Do you get more blade vibration with the ZCI rubbing against the blade? It might not be adding sufficient resistance to tighten up the nut, but could be causing some vibration that is decreasing the friction holding the nut tight.

Just a thought. I'll be curious to see if the nut loosening recurs when you put the ZCI back in. Maybe cleaning everything resolved it.

Todd

 

[Travis Porter]

Re: Tablesaw arbor nut comes loose

Heard back from WHM tool group yesterday. Got a phone call and an email with two different answers.

The guy on the phone was hooked on the arbor and the bearings. The email said that it could be the threads wearing out and that the arbor nut was the likely culprit.

I got pricing from them for the arbor assembly which includes the arbor, bearings, locking pins, and nut is $79. Chepaer than I would have thought. So, I am going to bite the bullet order the arbor assembly and two new belts. If it is the arbor/bearings it is not something I look forward to changing. It looks like I will have to take the top off the saw just to get to it good.

I took Bruce's recommendation and shifted the belts around on the saw last night and put the ZCI back in, but I haven't used the saw enough to have any confidence that it has done any good. Once I get the parts I can go through the process of elimination.

I really can't complain. The saw is 15 years old and this is the first time I have really had to do anything to it.

 

[sapwood]

Re: Tablesaw arbor nut comes loose

Travis, I think replacing the arbor assembly will remedy the problem. With a 15 year-old saw the new bearings will make it run so much smoother and quieter. Of course, removing and replacing the top will be a PITA. :roll: Thank goodness I had a cheap saw. The Griz arbor, bearings, and nut only cost $24 shipped. :eusa_shhh

Good luck,
Roger

 

[Travis Porter]

Re: Tablesaw arbor nut comes loose

I shifted the belts as Bruce suggested, and it hasn't come loose in almost a month. If that fixed it, which it appears it did, I still don't understand why it fixed it.:eusa_thin

I did get the arbor, bearings, nut, and belts. Since I am going to make a new extension table, I may go ahead and replace them anyway.

 

[Grgramps]

Re: Tablesaw arbor nut comes loose

Travis, I'll take a guess. I think that anything that would place a drag on the rotating assembly, including motor, belts and bearings, but not the blade, at the time power is shut off could cause the nut to loosen due to the inertia of the blade. By rotating the belts you have reduced the drag (or at least distributed the drag) caused by their set. All of these parts create drag, but my guess is that you have reduced it enough to resolve the problem. Sorry, I can't prove this.
(Thinking about this idea makes me wonder if the nut would have ever loosened if the power was only turned off while the blade was cutting.)
Roy

 

[Travis Porter]

I got my new extension table built, and a buddy of mine came over and talked me into going ahead and doing the arbor change out on my saw. So, we take it all apart, fence rails, extension table, wings, top, motor, and go to town.

Once you get the pulley off, the arbor itself is a shaft, two bearings on the outside, a metal collar, and a piece of spring steel to keep it all snug with lock rings on the outside to keep it together. I get the assembly out, and low and behold, the arbor assembly itself has been slipping some. There is an allen screw in the top of the cast iron assembly that tightens on to the metal collar and it wasn't tight.

After taking the old arbor off and spinning the bearings, you could hear a little noise in them, so I went ahead and put the new one in with new belts. I went ahead and turned it on, and I can say it is a whole lot smoother.

Fernhollowman was over last night and commented on how loud it was when I turned the saw off. Well, that is no longer the case as it is very smooth now.

Unfortunately, now I have to finish putting it back together and lining everything back up.:-(

 

[McRabbet]

Well, if it's any consolation, it sounds like you found the cause of the "back-pedaling" arbor nut!

Rob