TS Problem

[Brad Olson]

Should a contractor saw make any noise when turned off? I just acquired a PM64a and when you turn the power off it makes kind of a medium to high pitched vibration noise and it will do it two or three times as the blade slows down. I can't seem to figure out what it causing it but is isn't the motor, it is coming from the arbor area and I haven't tried a different belt yet.

With the belt off the arbor doesn't make any noise and turning the motor by hand does not results in any noise. It just happens during the brief time that the blade spins down.

Is there possibley a bearing or an area that needs a bit of a lube?

Thanks for the help, this is mystifying me.

[Jim Dunn]

Just from the sound of it it may be a bearing. I've never had any trouble with a table saw making that noise but I'm in an electric motor business and it sounds like something I've heard before.

[Tim Morton]

More than likely it is something that can be fixed by adjusting the pulley or the tension of the belt. I don't think its anything too serious. Try finding the owners manual and seeing if it references anyting about this noise. Barring that maybe move the pulley a scoshe in either direction and see if it gets louder or softer. I remeber having that with my saw ehen i first set it up...didn't take much to adjust it out and it hasn't returned. might help if you post a pic though, cuz there are people around here who might think you don't have a squeek, OR a table saw without a picture to go by :D

[Brad Olson]

Just from the sound of it it may be a bearing. I've never had any trouble with a table saw making that noise but I'm in an electric motor business and it sounds like something I've heard before.How hard is it to change bearings on a TS? If this is the problem can I just order some new ones and pop them in, or is it more difficult than this. I've changed bearings on farm equipment before, but not on machinery.

Thanks

[Jim Dunn]

Again as I've never had this type of problem on a table saw I'm going to guess that it will require some sort of punch to remove the old bearings and then some sort of press system to reinstall them. Probably much the same as the farm work?

Jim

[Marshall Harrison]

Brad, have you tried it with the blade off? IS the blade striking something or vibrating when you turn off the saw?

[Carl Eyman]

Resonant Frequency Every structure such as a saw, stand, motor, etc. Has a resonant frequency. If that frequency is within the range of zero to full speed rpms then the saw is going to vibrate when it goes thru that frequency. You don't notice it when the saw is starting and speeding up. The blade goes through the resonant frequency so quickly you don't notice it. but on the slow down it goes through it very gradually; so things start vibrating pretty violently.

This is the same phenomenon that leads a commander to have his troops go out of step crossing a bridge so as not to set up sympathetic vibrations.

My experience with this phenomenon is mostly second hand. My son makes his living doing this kind of analysis and I listen in awe as he tells me some wild tales. He tells me the resonant frequency of a structure can be changed very easily with adding a brace here or there. For instance. "c" clamp a brace from one leg to another and see if the vibration doesn't either disappear or come at a different stage in the slow down of the blade.

My saw does the same thing, but only while slowing down, and that doesn't hurt a thing. Whatever you do , don't go to a lot of trouble chasing a problem that isn't a problem.

If you are interested in more bs about this topic, I'll be glad to spout forth.

[Jerry Olexa]

Brad, had a similar thing happen on my first TS several years ago. In my case, it was a matter of adjusting/lightly lubing the pulley and then lubricating the belt. (These come in aerosol form specifically for belts ). The problem went away. This is a simple approach but might work.

[Brad Olson]

Brad, have you tried it with the blade off? IS the blade striking something or vibrating when you turn off the saw?Yes I did it with the throat plate off. After being suspicious of the bearings I went in and poked around underneath the arbor between the bearings and noticed a lot of dust build up. I should have looked more closely under the hood when I set it up since it is a used machine. I cleaned it out and then cleaned the sides of the bearings that were accessible and lightly greased the bearings. The noise has now gone away for the most part, but now another question...

The blade spins much more freely than before, but should you be able to "hear" the blade spinning when spun by hand? Or should it spin completely silently when spun by hand? Just curious if in a contractor saw if the table acts as a sounding board, because I can "hear" the blade spin when done by hand. It isn't very loud. I am just not sure what is normal since I have never owned or maintained a contractor style saw before (only cabinet saws and a Ryobi

I am now a bit worried that some dust worked its way into the bearings and could lead to damage to the bearings. I went and did some reading and apparently it isn't terribly difficult to change them, although not something fun to do.

Thanks for all the help, I just want to avoid a problem before it starts!

[Brad Olson]

Brad, had a similar thing happen on my first TS several years ago. In my case, it was a matter of adjusting/lightly lubing the pulley and then lubricating the belt. (These come in aerosol form specifically for belts ). The problem went away. This is a simple approach but might work.
I'll have to look into that, I've never heard of that before (even though I did go back and re-check to see if the noise was coming from the belt.

Brad

[Norman Hitt]

Brad, one other thing to check on a contractor saw is to be sure that all 4 adjustable feet on the stand are equally adjusted to stand firmly on the floor, because if one leg is touching the floor with slightly less pressure than the other three, ANY slowdown vibration that is present will be Greatly amplified. I have noticed this on my Buddys Rigid Saw, and a slight adjustment smoothes it right out.