<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Drilling into Polyester</title></head><body> <div>Gene,</div> <div><br></div> <div>Drilling into polyester is quite straightforward using twist drills. The trick is to have the drill bit very sharp with a lower clearance angle than normal, so that it won't bite into the material too quickly. I generally sharpen all my twist drills with a lower clearance angle than standard. This helps to prevent the drill from pulling itself into the work too quickly, with often disastrous results. As far as speed and feed rate is concerned, I like to have the drill going fairly quickly with a light application pressure. If the drill is razer sharp it will fall through the poly like its cutting butter. I usually cover the area over the hole to be drilled with masking tape before drilling. This helps to prevent any risk of perimeter chip-out. When I'm drilling lids for fitting rubber buffers, I run a couple of strips of wide masking tape on the panel adjacent to where I'm planning to drill, to prevent scratching and scuffing of the surface with the Portaline, which is the drilling attachment I use for holding the drill square to the panel.</div> <div><br></div> <div>While its easy to drill into polyester with low clearance angle drills, I recommend that you drill or grind away a clearance-diameter of polyester, down to the substrate, so that the mounting screws can't come into contact with the polyester. Preventing the risk of a crack developing. Once you've drilled your minor diameter hole for the mounting screws, you can cut away the polyester to the substrate with a larger drill to ensure that there is good polyester clearance from the outside diameter of the screw. This will prevent any risk of a nasty stress crack running out from the screw hole at some future time. Some caution is required when drilling away the poly to provide clearance, since the larger drill, with no material at the drill centre for control, can allow the drill to tear into the panel unless the feed pressure applied is very light. Another approach might be to drill your hole clearance first, being careful not to drill it too deep, then following it with the minor diameter drill. I generally don't drill the clearance away first, because it increases the risk of drilling the minor diameter hole off line. If you've got some tungsten carbide grinding balls and a die grinder handy, using these can be lot safer way of providing clearance for the screw after drilling the minor diameter hole, without risk of tearing up a piece of polyester.</div> <div><br></div> <div>Ron O.</div> <div><br></div> <blockquote type="cite" cite><font face="Arial" size="-1">Have a client that wants the 9"x1" hinge installed on the music rack - it originally never had one "</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">The piano has a high gloss polyester finish along with some very fancy veneer on the music shelf.</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Drilling into poly makes me a bit nervous - never did it before, expecially in such a visible area of the piano -</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Is there a technique that someone uses to dimple the spot to drill so that the poly will not split, or to prevent the dirll bit from wandering? Accuracy is a must.</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Regards,</font></blockquote> <blockquote type="cite" cite><font face="Arial" size="-1">Gene Nelson</font></blockquote> <div><br></div> <div><br></div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:ron@overspianos.com.au<br> _______________________</font></div> </body> </html>