<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Making bridges</title></head><body> <blockquote type="cite" cite>What's a scarf joint?<br> <br> David Love</blockquote> <blockquote type="cite" cite>davidlovepianos@earthlink.net</blockquote> <div><br></div> <div>A scarf joint is a variation on a butt joint, which instead of being vertical, is leaned over at an angle to present a longer and stronger gluing surface between the pieces being glued. A good scarf joint can be approximately 90% of the strength of the wood. We use Titebond Extend for all scarfs since it has a tensile strength of around 3,600 psi.</div> <div><br></div> <div>However, a standard scarf joint will result in the two pieces being in a line, which is not satisfactory for the manufacture of a bridge. The joint required for bridge manufacture is the compound scarf joint, which has the standard angled scarf joint<font color="#0000FF"> (typically angled at a slope of 1 in 5)</font> with an added angle to cause the two pieces to be joined at an angle. This is necessary to allow all of the bridge stock to follow the outline of the bridge. Once all scarfs are joined<font color="#0000FF"> (usually there are two per long bridge)</font>, the bridge outer profiles are then cut out with the band saw.</div> <div><br></div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div>_______________________<br> <br> OVERS PIANOS - SYDNEY<br> Grand Piano Manufacturers<br> <br> Web: http://overspianos.com.au<br> mailto:info@overspianos.com.au<br> _______________________</div> </body> </html>