I placed a couple of orders to this company recently and their pricing seems competitive. They also gave very good communications during the order. I have no afflilation with them - Just passing along a possible source.
I particularly liked this handy item for grinding laps, etc. - has a 1/4 spindle, and also converts to 5/8x11 threads for grinders/sanders. They have some nice hand-sanding items too.
http://www.abrasives4sale.com/holders.htm
Best,
Herb B.
