Agree with you both on the benefit of a lube (for cloth and capstan) but often find you need to add a bolster behind the wippen heel cloth to get a lasting result. Steam the dimple out of the cloth, but support it with a (bushing cloth) bolster, or in a few weeks your hammer line may sag. Regarding bolstering knuckles, rather than worry about the risk of *changing* geometry, we should think more about *restoring* it. If it's worn, the geometry, and a whole lot more is already gone. (sorry Maam, "saving the ivories" has always been more of a *prevention* thing :>) Choose material to make sure your bolster will *exagerate* the original profile, then work it in (burnish it, pound it, whatever) until you've restored the original dimension. Then you can regulate. (don't dress/file the buckskin until it's bolstered and tight) >From experience and mistakes, I think the art in working with worn parts is recognizing what's *reclaimable* (how much life is left in the material) and what is *missing* (resilience, fiber) and needs to be replaced. The neat lesson is that when you address a problem at the root cause (restoring compacted heel cloth) instead of jumping for the "easy button," (capstan wrench) much of the original regulation is automatically restored. (afterall, the capstans didn't wiggle themselves down... did they? ;>) Several years ago I uncovered some (more) serious flaws in my approach to regulating: 1.) Just because a pianos is new or nearly new doesn't mean the parts won't need some attention before regulating. 2.) There is no good reason to regulate an action with worn parts. As a result, a parlour-regulation on a 5-10 year-old Kawai-aha may really need a new set of knuckles. Meanwhile, the wippen heels on a fifty-year old WNG action may be fine with steaming/bolstering, and still fine, even five years later. It starts with recognizing what the essential properties of any given part need to be in order to function best, then purposing to fully restore that property, before tackling the regulation. Can't say I've seen that wippen-cloth that *needs* sanding just yet Fred, but am warming up to the idea of touching up the let-off buttons. After all assuming that something's right, just because it's *brand new* could only lead even more of that problematic assumptioning... "Amen Ron?" best regards (and intentions ;>) Mark Cramer, Brandon University -----Original Message----- From: Fred Sturm <fssturm at unm.edu> To: caut at ptg.org Date: Sun, 15 Mar 2009 10:17:09 -0600 Subject: Re: [CAUT] Worn whippen cushions / VS Profelt On Mar 15, 2009, at 7:59 AM, Chris Solliday wrote: > you don't need to sand, retaining all material and removing the > indentation > with the liquid swell is sufficient and allows the material to last > longer. OTOH, when working with letoff punchings, it does make sense to sand a bit. The idea being that you want the same amount of material everywhere, and some fibers will have disappeared from the dent or dents. So you want to remove that same amount of fibers from the rest of the surface. When you turn the button, it is likely that a slightly (or dramatically) different area of felt will contact the jack tender. If everything is as even as it can be, you will have more stable regulation. For the wipp cushion, if the dimple is fairly deep, my notion is that there is some additional friction because more surface area of the cushion is contacting the capstan. So a bit of sanding isn't a bad idea (and then iron down the fibers). You don't sand in the middle of the dimple, just the thicker cloth around it. Ideally you replace the cloth when it is at that point. I guess the same would really hold for moderate dimpling. Ideally you have two convex surfaces contacting each other. It doesn't last, whatever you do. But lubrication is more important: prevention rather than cure. For me that means teflon powder on felt, McLube on metal (and polished metal without corrosion or burrs). Both wear and compaction can be reduced by a lot even with extra heavy use. Re-swelling felt is a good method of getting more quality life out of parts, but you get more bang for the buck out of lubrication. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
This PTG archive page provided courtesy of Moy Piano Service, LLC