I'm working on a fail safe brake along the lines of an elevator safety
brake -- it will prevent a heavy load from falling if the supporting
roller chain breaks. I need brake pads that can be attached to the
device that will bear on a large rectangular tube column when
activated, 4 pads near the corners of the column. I found some rough
dimensions online of performance auto disc brake pads that are about
2" square, which seems appropriate. The four pads will be required to
support about 3000 pounds total.

Potential problems with automotive pads? Any suggestions other than
auto pads? McMaster has lining material, but I'd rather not design and
fabricate something that can be more easily purchased.

--
Ned Simmons