Rob writes: >Regarding reamers, I'm hearing that it's hard to get accuracy. Also, none >of the respondents gave their recommendations for actual reamer size versus >actual pin size. I would think this is the most important factor in getting >good torque. > Also, what about using a drill >bit of proper size instead of reaming or cleaning, and (assuming I mike each >pin and try to get good consistency, how many thousandths undersize would >you drill? I agree, it is time for the numbers. What is desired is a consistant result, first, then the decision can be made how tight. I use a drill bit, and grind the first inch or so into a non-cutting smooth taper(slight, maybe losing .010 of diameter at the tip. This allows the bit to get aligned in the hole before removing wood. There is no chance of the first time user doing 250 holes perfectly, so you absolutely have to practise the technique on an old block. This is a delicate skill, and how many delicate skills are done well the first time? With the proper size bit,(i.e., easily replaced reamer....) picked and ground, I use a 1/4" drill for it's lightness. The sensitivity part is simultaneously guiding it down straight and not letting it go down so fast that it digs in. The former requires softness of touch, the latter requires strength. Get used to the speeds that grab, or what it feels like to run in and out effortlessly. The cleanest results seem to come from full speed, medium feed. It requires practise and can be learned in about a half hour. I control the heat with a nearby tube filled with alcohol and water. I don't ream to 3/0 pins, there is so little margin of error there, with tolerances from three elements stacking up that I go to 4/0 if the block is the least bit inconsistant. For sizes: I have nice results from using a .280" ream for 4/0 pins. The 2 1/2" lengths are preferred. On an older model Steinway, this will usually begin my torque readings at 120 in/lbs, which drops to approx 110-100 in the first year, and stays there. Hope this helps, Ed Foote
This PTG archive page provided courtesy of Moy Piano Service, LLC