<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Hi John,<DIV><SPAN class="Apple-tab-span" style="white-space:pre"> </SPAN>I think we will probably agree to disagree on a number of these things.<BR><DIV> <SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "></SPAN></SPAN></DIV><BR><DIV><DIV>On Sep 11, 2007, at 1:21 PM, John Delacour wrote:</DIV><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">For a short while a long time ago I did burnish with a smooth broach, creating more or less heat, but I quickly gave that up and now never burnish or do anything that will "iron" the bushing cloth (it is not felt!).<SPAN class="Apple-converted-space"> </SPAN></DIV></BLOCKQUOTE><BR>In fact, it is felted cloth. The process of making center and keybushing cloth involves a great deal of felting, including agitation, pounding, heat, pressing, etc. It's woven, then felted.</DIV><DIV><BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Any heating or pressing of the cloth produces very unpredictable results.<SPAN class="Apple-converted-space"> </SPAN>I strongly deprecate such a practice.<SPAN class="Apple-converted-space"> </SPAN>If it has been done, it would be best to leave the bushings unpinned for a day or two before commencing centring.</DIV></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>I don't know that I agree with the notion that it produces unpredictable results. If you use a standard, carefully controlled process, you will get very predictable results in my experience. For me, in this case, it means precisely the same number of back and forth polishing moves at the same speed for each bushing (a kind of norm is maybe ten back and forths within 2 seconds). Assuming we are starting out at a reasonably consistent point to begin with. And it would seem to me that leaving bushings unpinned would be counterproductive in the process of getting them to a stable state.<BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Before I start a centring job I make sure that the parts have acclimatised to normal room environment by keeping them there for a day or two.<SPAN class="Apple-converted-space"> </SPAN>I use a broach about 5" long roughly the same size as the new pin and roughen it so that I will achieve the desired degree of friction with about five passes.<SPAN class="Apple-converted-space"> </SPAN>If the broach is too slow I roughen it more and if it's too fast I dull it with a few strokes of sandpaper.<SPAN class="Apple-converted-space"> </SPAN>To use a broach that is too dull and requires ten or twelve passes is simply a waste of time and energy, and too sharp a broach does not allow the fine final adjustments unless very special care is taken.</DIV></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>My experience with the method you describe is that my results will last very little time at all in a heavy use environment (which is where I do almost all my pinning). A degree of friction achieved only by passing a roughened broach through the cloth will, in my experience, drop from, say, 5 grams to 1 or zero in very short order. Some degree of burnishing is utterly essential, in my experience. Otherwise you end up with a center that has not enough firmness, and whose friction is very unstable. I have come to the conclusion that more burnishing is better than removing material, the heat and friction providing the modest packing and reduction of dimension I desire, ending with a firmer condition of the felt.<BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">When I started out in the trade I used to use talc for lubrication as well as the trace of oil from dragging the pin through my hair, but I now use no magic powders and have no plans to use teflon or anything else.<SPAN class="Apple-converted-space"> </SPAN>As Ted and I have mentioned before, it is common to find a well-used piano a hundred years old whose centres are still very good, and yet here I read of someone recentring every few years, presumably using some modern method.<SPAN class="Apple-converted-space"> </SPAN>At that rate the action will not reach 20 years, let alone a hundred!<SPAN class="Apple-converted-space"> </SPAN>If I needed to re-centre after ten years I would severely question my methods and materials.</DIV></BLOCKQUOTE><DIV><BR class="khtml-block-placeholder"></DIV>I use Protek as a standard treatment in all re-pinning jobs. Firm and lubricated is my general watchword. Heavy use pianos whose actions last even 30 years are exceptional, in my experience. It's not the centers that go first. Keeping a piano at performance level involves new parts at regular intervals, and I don't find any problem with that whatsoever. Sure, it's lovely to see a piano 100 or more years old in wonderful condition. I see a few myself. But not at the university.<BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">JD</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> </BLOCKQUOTE></DIV><BR><DIV><DIV>Regards,</DIV><DIV>Fred Sturm</DIV><DIV>University of New Mexico</DIV><DIV><A href="mailto:fssturm@unm.edu">fssturm@unm.edu</A></DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV><BR class="khtml-block-placeholder"></DIV></DIV></DIV></BODY></HTML>