Steel Drums Versus Rubber Drums on Widebelt Sanders
The choice depends in part on how you want to use the machine. March 28, 2010
Question
A comment was posted on a previous thread I started regarding widebelt sander power regarding steel contact drums on the first head. I have been investigating that further since then. Several of the manufacturers offer grooved steel rollers of six inch diameter on the front head. The other offers a rubber coated roller of eight inch diameter. Which is better?
Forum Responses
(Solid Wood Machining Forum)
From contributor H:
Depends on what you want to do with it. Having a lot of HP and a steel drum they are used for thickness sanding/planing. With a rubber roller it will take off less material but have more finesse. If you are buying a sander get a rubber contact drum with a platen. If you want to plane with it get a steel head with about 60hp.
From contributor D:
A lot depends on how you intend to use it. Steel drums are better when using coarser grit. The rubber coated drums are more forgiving if using fine grit, and if all things are equal, the larger diameter drum gives a slightly larger contact point on your stock. In my experience belt length is a more measureable indicator of "better," as usually everything else follows that (diameter, hp, beefiness of the machine, etc.). Platens will increase your contact point more however, and a benefit is a reduced chance that a small part will pop a wheelie while going through the machine (as do shoes between multiple drums), with the trade off being a bit longer crossgrain scratch. The only real way to judge a machine is to test it with your application and see how they perform.
From contributor S:
These responses make sense to me which is why it is very strange to me that the machines with the steel rollers are the ones with the lowest horsepower to inch ratio. I should point out that the rubber on the first contact roller is much harder than the rubber on the second. The machine is being used as a sander not an abrasive planer in any case.
From contributor J:
Rubber will wear out at some point if someone doesn't gouge it first with an oversize piece or small part wheelie. Barring an accident though, the hard rubber will last a long time. A steel calibrating head should perform marginally better on knots, glue beads, and other hardness variations.
From contributor R:
One other consideration is that the steel contact drum is not very forgiving. The joint on the belt will leave a mark across your board as it goes over the steel drum. The rubber drum would cushion the lip in the belt and not transfer it onto the panel. Also if you break a belt and damage the steel drum you will have a much more difficult time fixing it. A rubber drum can be re-calibrated right in the machine. I would agree that the steel drum is only good for calibrating or I would recommend it if you are considering a three or four head machine as you can take out any deficiencies left by the steel drum by the second and third heads. One head is not enough to take out the mark left by the belt joint.
From contributor J:
Belt selection is also a big part of splice marks. I went to Sia paper belts and no longer have an issue with them, on steel or rubber drums. I often had an issue with cloth belts on the steel head, though the second head took care of them. One other random comment is that you can run a combi head with two contact points - drum and platen. This gives you the benefits of a contact line (more focused pressure on high spots) and a distributed contact patch (averages out pressure and scratch marks).
