Finally figured out why my 15hh surfaces clatters

[Roger Feeley]

From the beginning, my powermatic 15hh surfaces has intermittently made this clattering noise. It’s on warranty so I’ve not worried too much but it bugged me. It was pretty weird because it seemed to stop the instant I turned the machine off so it would spin down silently.

I called PM about it and their tech support guy had no answer.

so I opened up the cabinet, lifted the motor and removed the belts. It took about two seconds to see that the motor fan impeller was very loose and was clattering against the shroud. Tighten a set screw and problem solved. My guess is that the impeller was loose at the factory.

So I called PM tech support and told them. I was assured that if another customer complained of “clattering” they would be directed to check the impeller.

[Andrew Hughes]

Mine doesn't rattle but it does thump when it starts. Just like a newer unisaw does. Does your pm15 thump Roger.

[Roger Feeley]

Mine doesn't rattle but it does thump when it starts. Just like a newer unisaw does. Does your pm15 thump Roger.
there is a slight thump that I attribute to the high startup torque and a whole lot of mass that it has to spin up. I think my delta 6” jointer thumps.

My Sawstop ICS doesn’t make any thump. I don’t think my drill press ever thumped but the mass it was spinning up is minimal. Now it has a three phase motor with VFD so the startup is controlled.

[Thomas Crawford]

I have a 15HH I rebuilt. The thump is the belt hitting the enclosure. You can lessen it by tightening down on the motor mount to increase the tension.