Basic belt sander question

[Carl Beckett]

Ok, this is a really basic question so forgive my ignorance (and I could go out and do internet research of course, but get much richer experiences here)

Do all belt sanders have a platen? Or most of them? Or any of them that are worth a dang?

I have seen ones that are really just two drums, and the belt runs between these two drums. This makes it for all practical purposes - a drum sander (just uses a belt as the abrasive). Or maybe its this added surface area of the belt that gives it the real benefit? (cooler running, longer wearing)? Maybe some have three drums? (not sure the benefit of the addition drum if thats the case - maybe to use a longer belt?

I guess I just assumed they all had a platen, but learned that is not the case. I can see how a platen would sand a much larger area at a time, etc.

Has anyone had experience with all three? (drum sander, belt sander, belt sander with platen?).

I can also see that some type of oscillation would be great.

[Brian Kent]

I get confused with different terms.

I have a hand-held belt sander that I use very little.
My Delta 18-36 drum sander gets used continually.
My Grizzly 6" x 48" combo sander is also very useful, especially on the belt sander side.

Which kind of sander are you asking about?

[Carl Beckett]

Sorry Brian, I was wondering about small stationary belt sanders. Typically start in the 15" range (overhung arm). And go up from here. The drum sanders tend to be like the Performax 16" overhung, or up to small dual drums (like the 24" dual drum) - which start overlapping small stationary belt sanders.

Its my understanding that you have to go up a couple levels to get to a platen design.

But these small belt sanders - without a platen where its just a belt wrapped between two rollers - seem a lot like a drum sander to me (but with a belt of abrasive instead of abrasive wrapped around a drum)

[Mike Hollingsworth]

I had an open end Powermatic with a platen I never used. When I upgraded to a Shopfox 20 I didn't care that it came with no platen. Oscillation is the key.

[J.R. Rutter]

OP - you are correct. A wide belt sander without a platen is still miles ahead of a drum sander for speed and surface quality. The drum itself is softer rubber, and is usually vented. The added surface area of a belt means that it runs cooler. That and the oscillation means that they don't load up as easily. I ran some tests this year with platen / no platen for a final finish pass at 240 and while the platen did leave a finer finish, the drum only was very close. I have not seen a 3-drum arrangement that did not have a platen between the two lower drums, but even if there was no platen, you could position the second drum to have a light contact and potentially get a better finish, which is what you should be doing with a platen anyway.

[johnny means]

The three drum models I've seen usually had a removable platen between the two lower drums. This allowed the user to use the machine as a drum style sander when the need arose. Often times the platen gets tossed aside and forgotten after some dunce over loads the machine and destroys the felt.

[Rick Lizek]

A platen and oscillation is what sets a widebelt above a drum sander. The platen is what puts it to the level of a stroke sander which is a fantastic sander at an affordable price for a small shop. Drum sanders are low on my list of must have machines.

[Jim Andrew]

My Grizzly 9983 is a great sander. Has a double bottom roller with platen. It is a small open end machine, but works fine for me. Still go over my panels with a ros, but have gone to surfacing my boards down to 7/8", using the sander to sand down my panels with 60 grit, then down to 120 grit and then ros before assembly. I rotate the panels as feeding through the sander, and the panels come out completely flat. The secret to success is to get all the glue off your panels before using the sander.

[Larry Prem]

Regardless of how many drums are used to mount a belt, a single belt is mounted on what is called a sanding head. Each head mounts a belt, and sands the piece as it passes through the machine.
There are drum types, and platen types. Platen type heads produce a better finish, but are more expensive (they have more parts).

Wide belt sanders are configured to produce results in a single pass. Choose how many heads you want, and what type. For example, a drum head for the rough cut, and a platen for the finish. The two platen head version would be more expensive; and would not necessarily perform any better better (because the second head is a platen head on both machines).

Drum type heads are superior to a simple drum sander, because the belt has many times the surface area of the paper on the drum. You'll change the paper on the drum many times before a belt wears out.

Here's a list of just about all wide belt sanders you can buy
http://www.hingmy.com/WoodworkingTools.php?Type=12