<html> <head> <style> .hmmessage P { margin:0px; padding:0px } body.hmmessage { FONT-SIZE: 10pt; FONT-FAMILY:Tahoma } </style> </head> <body class='hmmessage'> I ended up using clamps and removing ONE plate screw at a time, drilled out the hole and installed 5/16ths stove bolts with the falt top and cone shape underside; they fit like a glove! Even at full tension, I got some epoxy to squeeze out a bit. I replaced 5 out of 7 bolts. The only two not replaced were right at the bass break, because those screws were just an 1/8" from the top..too close for comfort, especially if the existing canal hole is off a bit from the factory (as all the others were slightly) and angled UP it could come through the top of the block! So I'm hoping 5 should suffice. Good news is that the crack in the area of those two remaining screws is narrowest! Thanks to everyone for the great tips and advice! Terry Peterson <blockquote><hr>From: pianoforte@pianofortesupply.com Subject: Re: Upright pinblock question Date: Sun, 28 Oct 2007 10:04:29 -0700 To: pianotech@ptg.org I would not use a lock washer. I'm no machinist, but I would think that the lock washer would serve a better purpose when joining metal parts where there is no compression.  By tightening the nuts in your case, there is some wood compression which will keep tension on the system and prevent loosening  of the nut. (I'll gladly stand corrected...) Jurgen Goering Piano Forte Supply (250) 754-2440 info@pianofortesupply.com <a href="http://www.pianofortesupply.com" target="_blank">http://www.pianofortesupply.com</a> On Oct 28, 2007, at 8:33, pianotech-request@ptg.org wrote: <div class="EC_EmailQuote">PS: Again, should I use, or do I even need to use locking washers over the standard washer to help keep the nut snug? Terry Peterson </div> </blockquote> <hr />Help yourself to FREE treats served up daily at the Messenger Café. <a href='http://www.cafemessenger.com/info/info_sweetstuff2.html?ocid=TXT_TAGLM_OctWLtagline' target='_new'>Stop by today!</a></body> </html>