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thoughts on a quality belt sander to be used in conjunction with a ROS?
BC,
Fine Homebuilding did a Belt Sander review in this month's issue. A Dewalt came out in first place. That said, I have some questions/issues with the review.
I happen to have the Makita 9903, which was also included in the FHB review. The FHB reviewer mentioned that the 9903 as not having an options to use it as a fixed sander. Obviously unbeknownst to the reviewer, the 9903 has the ability to be clamped to a table on its back or side, and becomes a decent fixed belt sander. These are built in, not options. Hmmm... One might consider the MFT a decent place to clamp it!

Also the reviewer bemoaned the fact that none of the sanders had good quality, flexible dust collection attachments. Obviously, he wasn't aware that a $7 Fein hose adapter can be cut down in two minutes to PERFECTLY fit the Festool 27mm hose and the 9903 dust port. A CT22 hooked up to a Makita 9903 gives almost perfect dust collection.
Here's a pics of my D27 hose hooked to my Makita:

Since you have a medical problem with dust, I would strongly recommend that you toss your old belt sander and run (not walk) to get a Makita 9903.
Dan.
p.s. They make a sanding frame for the 9903 too. They call it a sanding shoe.
p.p.s Here's the hose adapter for $7.50:
http://www.amazon.com/Fein-921072K13-Step-Adaptor/dp/B00005M1SW. Mine was about $5 at Woodcraft.