It is very nice. Since I am soon taking up this sort of adding a disc sander to my 3x21 belt sander, I had seen your built and write up very closely and I liked it very much. Numerous photos from different angles and for each stage of built is very useful for me to understand the build clearly. Thanks for sharing such detailed post on this forum

Mine is a hand held belt sander and doesnot provide a ready flat surface to mount it in a horizontal position, to that extent i have to modify the build, I have procured a 10" turned wooden disk and also a 12" 120 grit sanding paper which i can paste it on the disc.

Once i complete the built i would share the details.