Drum Sander Sanding Marks

Drum sanders typically leave "washboard" contact marks, so that sanded pieces still require hand sanding with a random-orbit sander. March 13, 2007

Just got my 50" Woodmaster drum sander. Seemed to be working great until I stained a number of small ash table tops. There are lines running sideways through the panels, starting 3 inches in from the end. Has anyone had a similar problem with these and found a fix?

Forum Responses
(Solid Wood Machining Forum)
From contributor T:
Sounds like what is called "snipe" and is impossible to prevent unless you send an equal thickness piece of wood in front of and behind the panel being sanded. I sand the snipe out on the stroke sander. Besides, there are usually slight ripples from a drum sander, so re-sanding with a stroke or large random is best anyway.

From contributor J:
Usually those lines sideways through the length of the piece are caused by the seam in the belt. If you stained a board (not sure what that means), you might have bumped something out of perfect sync and now the belt hits heavy on the seam.

From contributor F:
We have the 38 inch model, and never finish anything straight out of it. We always run a RO after.

From contributor R:
The drum leaves contact lines. I wouldn't consider that snipe... totally different issue. You must random orbit sand anything out of a drum sander. A widebelt with a platen can have parts ready for finishing right out the sander. People don't seem to realize how important the platen is on a widebelt until you use one.

From the original questioner:
Thanks. I have since been sanding with the RO afterwards with 2 grits and on my most recent table top I still had that washboard effect. It was only noticeable after several coats of finish. It seems redundant to have to sand so much afterwards - I was getting better results with the RO out of the planer; at least I could see the marks needing to be sanded off. I am rather disappointed with the drum sander.

From contributor F:
These things seem to work best if you make very light passes, 005 or so. We mainly use ours to rough sand panel glue ups before we run them through the shaper. Lately we have been getting more work for rustic, distressed doors and cabinetry and have been sanding with 80 grit, wire brush by hand and finish. Clients seem to love it and it sure is a lot faster.