Thanks Jim. I had forgotten rate of penetration, having an effect as well. I must save the info this time. Although, I usually use a scrap piece of pinblock, and experiment with the insertion rate. One should always direct a stream of air at the bit. If one had spare money, one of Webb's vortex coolers is ideal. Regards, John M. Ross Windsor, Nova Scotia, Canada jrpiano@win.eastlink.ca ----- Original Message ----- From: <JIMRPT@aol.com> To: <pianotech@ptg.org> Sent: Wednesday, June 18, 2003 6:59 PM Subject: Re: Bolduc Block - Bit Size - Torque > > In a message dated 18/06/03 5:33:22 PM, jrpiano@win.eastlink.ca writes: > > << The speed you drill at has an effect on the size of the hole, one way the > > hole is larger, the other smaller, with the same size bit. > > I forget which is which, but too fast is no good and neither is too slow. > > Possibly someone can remember the speeds that should be used. >> > > John..... you are in agreement with my thoughts here. There are many > variables as to the answers and among them are, speed of drilling (not only rotational > speed but vertical penetration speed), sharpness of bit, type of bit (shape > and structure of point), single pass/double pass, type of block being drilled, > whether bit is cooled frequently, etc., etc. > > In my experience the slower you drill a hole the larger the final product > with a faster drilling speed producing a smaller hole...but that is just my > opinion and is backed up with no objective evidence. > > I drill my blocks with 600/800 RPM and use a .250 bit for 2/0 pins. This > works very well on multi-layer blocks as well as S&S/Bolduc type blocks. Single > pass, two insertions per hole. With this combination, and the use of pin > driving fluid, I end up with very workable chipping/tuning torque values which > settle down to a very nice 'regular' tuning value. I believe personally that values > of over 150 are overkill not to mention counterproductive.....but that is > just my opinion. > Jim Bryant (FL) > _______________________________________________ > pianotech list info: https://www.moypiano.com/resources/#archives >
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