<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv=Content-Type content="text/html; charset=us-ascii"> <meta name=Generator content="Microsoft Word 11 (filtered medium)">  <style>  </style>  </head> <body bgcolor=white lang=EN-US link=blue vlink=purple> <div class=Section1> Hi David,<o:p></o:p> Yes I do use the Dragon skin paddle below the staple it is very rough and with good control you clean and <o:p></o:p> file at the same time. This is a before and after hammer, I first used the dragon skin paddle then an eighty grit sanding paddle.<o:p></o:p> <o:p> </o:p> I bought the dragon skin at a camping store???   about 10 years ago, bought a couple of sheets made a few paddles and have used<o:p></o:p> them ever since, probably will last a lifetime.<o:p></o:p> <o:p> </o:p> Best,<o:p></o:p> Jack Houweling<o:p></o:p> <o:p> </o:p> <o:p> </o:p> <o:p> </o:p> <img width=465 height=262 id="_x0000_i1034" src="cid:image001.jpg@01CBE1CD.5FA07E50"><img width=460 height=259 id="_x0000_i1038" src="cid:image002.jpg@01CBE1CD.5FA07E50"><o:p></o:p> <o:p> </o:p> <div> <div class=MsoNormal align=center style='text-align:center'> <hr size=2 width="100%" align=center tabindex=-1> </div> From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On Behalf Of David Boyce Sent: Sunday, March 13, 2011 12:19 PM To: pianotech@ptg.org Subject: Re: [pianotech] Cosmetic aspects of filed hammers<o:p></o:p> </div> <o:p> </o:p> Thanks for your responses folks. Alan, you say <o:p></o:p> <o:p> </o:p> <div> <div> David, <o:p></o:p> </div> <div> Did you remove the hammers and place them in groups in a vise to dress the hammers, or do them in situ?<o:p></o:p> </div> <div> On this 1883 Bechstein I used French chalk to whiten the hammer surfaces and then vigorous brushing with a nailbrush.<o:p></o:p> </div> </div> I did them in situ. I've never removed a sert of hammers just for filing. In what form was the french chalk you used? One of the little rectangular-profile sticks? I think your screwdriver idea is great! It exactly solves what I observed to be the problems with the mini-drill tool. That is, lack of torque means that 1) it's hard to keep a constant speed and 2) you can only use a wheel of small diameter.  The power screwdriver/sandbobbin approach solves both problems! A power screwdriver is bound to have MUCH more torque than the mini drill.  Can I ask what glue you use to stick the sandpaper to the bobbin? Also, you mention interestingly that you use the same setup but with steel wool on the bobbin, to revive strings.  How do you attach the steel wool? Joe, thanks for your comments <o:p></o:p> In the hand-filed photo, I was taught to start the filing further towards the tail than you did;  I start at least before the widest point, and often before or at the staple.  The reason for this is that if you start after the widest point (if you start closer to the crown), you are effectively  increasing the hammer radius at the crown, thus flattening the hammer crown.  This is illustrated by the exaggerated photo below. <o:p></o:p> I appreciate exactly what you mean. I do try to keep a proper profile, though I've never started as far back as the staple.  The idea of taking off a layer or "skin" of felt all the way round would certainly solve the problem of the grubbiness on the upper surface.  Mind you, there is the aspect of time and cost, related to the quality of the piano.  In the particular example I sent, and for that particular section of hammers, the filing does start nearer the nose the I usually would, but for those hammers it kept the profile OK.  I love the idea of frantically trying to glue back on excess removed felt!  I can't guess the brand of piano, by the way! John Ross, I do like the idea of using the sand blaster with glass beads. I've been thinking for a while about a compressor.  What else do you use the setup for, in addition to cleaning actions? Jack, you say <o:p></o:p> I have a special paddle I use, it is a piece of dragon skin I glued onto a paddle. It takes the felt off very quickly. I then go on to finer grits with various paddles<o:p></o:p> and sandpaper strips finishing off with 600 grit.<o:p></o:p> Do you start right back at the staple, and take off a layer of felt all the way round, as Joe recommends? It's really the "cleaning" aspect that I was asking about.  I wasn't familiar with dragon skin, so looked it up. Interesting. Where do you obtain it? Thanks again folks. Best regards, David Boyce<o:p></o:p> </div> </body> </html>