<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <body bgcolor="#FFFFFF"> Hi, I think you mean Robertson. I have never heard of Thompson. The Robertson was a Canadian invention. They are available in the US now, I just can't find the catalogue now. Sears in Canada has them. The normal sizes are 1,2 & 3. They have a very small one #0 and a larger one #4, which is what I think you need. Try your local Sears and see if they can special order, I know they have #0,#1,#2,#3 in the catalogue here, I don't see individual #'s, they are part of kits. You would be more likely to see them in a woodworking type store or catalogue. Feel free to contact me and I will dig deeper for a source. regards, John m. Ross Windsor, Nova Scotia, Canada. Nancy McMillan wrote: <blockquote TYPE=CITE><style></style> Hi list,A customer of mine has a Heintzman & Co. console, made in Toronto.  The pin block is pulling away from the back frame and I received the go ahead for the repair.  My problem is the bolts going through the plate into the block and back frame are Thompson bolts ( square recess in head of bolt) and I can't find any supplier in the U.S. with this large of Thompson driver.  The plate bolts have a square recess of 3/16" square or roughly 5mm.  I wouldn't mind being a set of Thompson drive sockets so I can tighten up a few other things on this piano.  Any suggestion for tool suppliers from are Canadian list members?ThanksDoug Mahard, Associate</blockquote> </body> </html>