Hello everyone, I received today a nice pamphlet coming from Renner Germany, that was send to me because I ordered a set of reamers (neat cool burnishes I received in fact). As I asked how they use these tools in the factory they send me the translation of a training that was given by a head tech for the German technicians in 95. A few points seem important so I will tell you about. The original pinning in Renner actions is machine done, when worn or too much play, we use to insert a pin one size larger (usually 1.300 mm original, 1.325 to 1.400 in repair mode.) For older instruments, using oversized cnterpin is not recommended, but what is called "complete rebushing" is considered that mean, drilling or pushing out the old bushing cloth and using a new one with a decently pin size. The important points I notice are : Relative humidity in the shop and customer's place is to be taken in account for these jobs. When extracting or inserting a center, we may always go in the same direction, than originally, that is, push with the center pin extractor on the side of the pin which was not cut and that is clearer (nickel plated sometime). The use of long center pins (25 cm or approx 1 " long) is said to be a better solution, as the insertion of the center burnish well the inside of the bushing. After reaming, burnishing is of prime importance, and may always be done in ONE DIRECTION only, so the fiber stay neat and well oriented. A "pinning plank" is done, to be hold in the bench cauls. It allows the use of the long center pins it is a hardwood plank with a large saw kerfs on the top, and possibly a little metal plate. After the pointed end of the long center is inserted thru the flange and the Birdseye, the part is laid on the plank, and the point of the center is hold in a flat pliers, then pulled thru all along preferently in one pass (while the flange is stopped by the plank). if one use pre cut centers, a burnisher is to be used, but it may as well be used in one direction only. For complete rebushing, with new felt, the strip of special bushing material may be hold in a wise, and all the flanges inserted at once after the bushing have been : sized, passing in a little metal plate drilled with 3 different holes (sold by Renner - dimensions of holes on demand) Graphited with a first class graphite stick as the one sold by Renner (no joking) glued on the external side with hot glue - pre-glued strips as sold by Renner have only to be misted with a sponge. 10 hours after it is possible to cut flush and ream the new bushing (30 min only with the pre glued material) They give a recipe for easing the pinning with a 5% water 95% distilled water to be used for hammers, or 70% alcohol and 30%water when the pinning may be more firm as for whippen, dampers, etc. They say also it is forbidden to use any oil on the bushings, because it cause soft bushing felt, stain on the flanges, accumulation of dirt, problems when trying to repin or rebush because the felt is not holding on the wood... For what is worth, nowadays the fiber direction and the insertion direction makes a lot of sense to me. Hope you have find some interest in these so well know things ! Another good trick : if the Birdseye is showing too much friction on the flange, (too thick) , press the flange - and work the part while pressed - with a "duck nose" or flat large pliers (as for dampers) that have a 3mm hole drilled on one side. That way the wood is burnished and friction lessened (the hole avoid warping of the center pin. Best to all. Isaac OLEG Entretien et réparation de pianos. PianoTech 17 rue de Choisy 94400 VITRY sur SEINE FRANCE tel : 033 01 47 18 06 98 fax : 033 01 47 18 06 90 cell: 06 60 42 58 77 >
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