<html> Hi Doug,<br>               The square socket screws and bolts are called Robertson's. I great invention if you need to place a lot of torque to the fastener with out the blade slipping. Pianophile sell a bit that fit's your tuning hammer, what a combination for tightness?<br> Regards Roger<br> <br> <br> At 09:51 AM 08/07/99 -0700, you wrote: <br> <font size=2><blockquote type=cite cite>Hi list,</font><br> <font size=2>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?  </font><br> <font size=2>Thanks</font><br> <font size=2>Doug Mahard, Associate</font><br> </blockquote><br> <br> <div>Roger Jolly</div> <div>Baldwin Yamaha Piano Centre</div> <div>Saskatoon and Regina</div> <div>Saskatchewan, Canada.</div> <div>306-665-0213</div> Fax 652-0505 </html>