<HTML><HEAD> <META charset=UTF-8 http-equiv=Content-Type content="text/html; charse= t=utf-8"> <META content="MSHTML 6.00.2730.1700" name=GENERATOR></HEAD> <BODY style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; BACKGROUND-COLOR: #fffff= f"> <DIV> <DIV><FONT= face="Times New Roman" color=#000040>     &nbs= p;   Glenn</D= IV> <DIV><FONT= size=3>  You'= re asking the hard technical questions. My engineer friend say that when his= friends get picky with details the comment is "hey your not building a pian= o ya know" I take that as a compliment. In this case we are but fortuna= tely board thinning isn't a mystery. It however helps to have an o= rganized approach to thinning. If you ask 5 belly guys how they do it you'll= get five different answers.</DIV> <DIV><FONT= size=3> &nbsp= ; The amount of thinning depends on what your goals is & what you think = is benifiacial to freeing up the edges of a board. The thinning in most regi= mines includes thinning along the spine(straight side), on around the tail a= round the curve and stopping short of the top treble area which needs no or = little thinning. So= me also thin along the belly rail up to the offset of the board ,which = is sometimes desireable depending on the overal thickness of the board to st= art.</DIV> <DIV><STRO= NG>  Thinning i= s mostly restricted</DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue = 2px solid"> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000= ff 2px solid; MARGIN-RIGHT: 0px" cite="" TYPE="CITE"> Glenn ,Ye= s I have & you are correct. First it's possible to take measurements aro= und the bolt holes with a wire caliper. 2nd small holes drilled behind = the bridge or around the edges & later filled with a toothpick is kosher= , but why would you wish to do this?    I've done t= his only once & that was to diaphramize a very thick board in a Yamaha C= -7. I also refinished the board afterwards so no big deal. The board was .40= 0 thick in the middle and tonally a bit stingy. Thinning it helped to reveal= a more lively tone i.e. better sustain.   Regards-Dale<= /B>= </BLOCKQUOTE> You've got me with "why would you want to", I admi= t to this recurring obsession to collect data, and that includes soundboards= . It is, you're right, academic only unless you're working on a board in pla= ce, but that brings one other question to mind. If you have a full board rea= dy to install, and you decide to thin it, how DO you measure your planing pr= ogress ? regards, Glenn</BLOCKQUOTE></DIV> <DIV></DIV></BODY></HT= ML>