Brian;
I too have used a 12 inch disc for decades and the detail work that can be done is significant as you discuss. The detail fine finish work on the modern soft recoil pads such as the de-acelerator pads can be problematic for some. My 12 inch disc is one of the older cast iron discs and when I bought the disc sander it's balance and runout was not to my liking and I took it to the lathe and turned the disc to zero runout and then I balanced it on the motor armature shaft. Like you I favor the B-square jig and it is a must to my way of thinking on using a disc sander as secondly a must is an adjustable table on the sander to get the correct angle of the pad (front-to-back).
In regard to the fine detail finish on modern recoil pads (yes the formula of the "rubber" has changed as well as the quality of the pad--right out of the factory carton). For ultra finish in the last steps of finishing the pad surface I do this: I turn on the sander and when it get to full speed I turn it off and let it coast down to about 1/2 speed and then sand the pad for fine finish. Sometimes I will have to do this 5-6 times, but with a cast iron disc it coast down for a long time.
Now, in the decades that have passed I think that it is likely that some of the new expensive long-belt sanders that have variable speed motors may be a better tool, although I have thought that I could built a 12 disc sander with a variable speed motor that would work just as well, without spending a couple of thousand bucks on a variable speed belt sander.
Steve says he uses a belt sander which is what he learned on. And I think that is good as when you learn how to do a task well changing to something else usually does not bode well.
Regards;
Stephen Howell
