Can any one give me some advice on how I can resolve the chatter that I am getting from my Bona 10'' belt sander I just had upper roller bearing replaced, drum trued up. Just sanded same red oak and could see same signs of chatter. I have a few dark stain jobs coming up and would like not too buff for days. Thanks for your help.

make your second to last pass at a slight angle 3-7 degrees final pass straight, buff as normal and stain away.

Thanks for your reply. This is how I sand and still getting chatter. There isn't alot, but I haven't stained the floor yet. That is my concern. It seems that when I use the finer grits 100,120 I get them but this last sanding it was with 80 grit. Maybe I'm being too fussy, but if I see them the homeowner will as well.

I'm curious about two possibilities. You are testing the sander on a floor that has chatter ? In this case, your machine is likely to follow the existing chatter and create new chatter as a result. So maybe your machine is actually cutting properly again but you don't see it.

I might suggest cutting the floor you are on at a 45 degree angle with 36 or 40 grit belts , whichever you prefer. This is going to cut across the chatter and should take it out . You could also mess around with a hard plate and sanding discs on a disc buffer to get one area chatter free.

My last thought is the belts that you are using. I have a Bona 10 inch belt as well but bought a hummel because the bona machine turned out to be a head ache for me. I can absolutely say that when I bought Bona blue 100 grit belts, I had to throw 1 to 2 belts or ever box away because they caused the machine to chatter. So I would literally try another 100 grit belt and the chattering would stop. If one of the 100 git belts is bad, you can literally hear it chattering and vibrating against the floor as well as see the chatter.

If you plan to stick with the Bona 10 inch belt, try Virginia,Norton,etc abrasive belts for your fine grits .3M is the best abrasive company out there but it's hard to locate 10 inch sanding belts.

I also recommend hard plating. If the chatter is from a 100 grit then these should buff out.

check your wheels, check your drive belts for proper tension. If the fine belts are the ones that are giving you a fit it may be the paper. If you look inside of a belt it will have the paper weight on there usually an X or a Y. Y weight paper is thicker and will hold its shape a ton better than the thinner X weight paper. Drum pressure spring could be wearing out as well. As a big machine ages the drum tension spring will get springier and springier like an old Cadillac. The spring doesnt have enough tension to hold the belt down right and ends up chattering. Low voltage will do it, try to keep your cord under 50' when you can.