If I can have only one sanding machine, which is more useful, a 20˝+ disc sander or a 6˝ to 8˝ edge belt sander?— Philip Glover
Tony Immorlica replies: I’d go with the belt sander. It’s so much easier to change sand paper on a belt than on a disc sander. You can change a belt to a different grit in a half a minute or less whereas replacing a disc is a messy job often involving scraping off the old glue or using a solvent to get the disk clean and flat. So you generally put on a medium grit and stick with it until it’s worn out. Plus, you cannot reuse the disk if you need to change grits often—hook and loop sanding disks are hard to find in large diameters.
Also, many belt sanders have a spindle which can accommodate a buffing wheel or even a small disk, and the belt can usually be oriented horizontally or vertically. You can also sand curved items on the roller, but it’s limited and not made for that purpose.
Disk sanders have their place though. The disk has a lot of momentum, runs smoother and is better for free hand sanding; you can also vary the aggressiveness by simply moving the piece you are sanding towards the center of the disk to decrease the rate of removal, or towards the outside to increase the rate. Just be careful not to burn the wood.
Owain Harris replies: If I could have only one sanding machine in my shop it would definitely be an edge belt sander and the larger the better. I use mine for everything from pattern making to surface sanding curved parts to dressing edges on straight parts. Because of the large surface area along the front of the machine, you can use it to make adjustments to cabinet doors while fitting them to an opening without worrying about creating divots in the edge.
If the table extends around the end of the sanding surface, you can also use it as a large drum sander for inside curves.
As with all machines in the woodshop, there are some safety issues to consider. There is a greater danger of losing control of a part on the edge belt than with the disc sander, particularly with small parts and round pieces. But as long as you pay attention to the direction that the belt is moving and work against it (as you would on a router table), then you shouldn’t have a problem. And it should go without saying that on any sanding machine, keeping fingers out off the way of the abrasive is key!
Bruce Wedlock replies: A belt/disk sander is by far the more versatile. The disk allows precision sanding to a line and the belt provides sanding flat surfaces. I have the Jet 6˝ x 48˝ belt and 12˝ disk sander and it is one of the most used machines in my shop. The larger the disk the better.