Greg Newell wrote; <<problems incurred when drilling a pin block are from the heat generated...pre drill?... dangers be in this plan?>> and <<favorite source or type for the drill bits needed?...type of bit I would use? Are there bit coatings I should use? Are better bits manufactured using coatings?...>> I HAVE to respond because drill bits and drill bit sharpeners are a kind of hobby for me. Drill bit technology has improved greatly in the past several years, and there are now many inproved tip designs, shank designs, new materials, and coatings, The best bits today put the old jobber bits to shame. If you have the right bits and equipment, step drilling successively larger holes to get to the final size is a waste of time and will not produce a better result. I would first suggest you use a split point, or some other advanced type point drill bit, of which there are many. ( Notch point - split point - Bickford point - helical, etc.) They are self centering and do not wander when starting. The split points automatically reduce heat generated because they cut right to the center of the hole, unlike standard jobber bits that crush the wood aside into the cutting edges. That "chisel edge" is where most of the heat originates. You should be able to drill the hole in one pass without a worry of heat damage with split point drills, IF they are sharp. The heat problem arises on the dense Delignite type blocks, not very much on the older types. IF you are using a hand drill (which I do NOT suggest), I suggest drilling a few thousandths smaller than final and using an actual fluted reamer, not a drill bit, to take the hole to final size. Drill bits do not make good reamers, and drilling in stages does not improve them. The accuracy of the final hole would be on the order of one or two ten thousandths of an inch if you ream the holes by hand with a solid carbide straight fluted reamer, not by using the reamer in a drill. This degree of accuracy is wasted because the tuning pins vary by ten times that amount, and they are a limiting factor, but the finish on the sides of the hole is better. There are "dreamers" available, and you can have them custom made to your specs., to .0005 accuracy. They are a combined drill bit and reamer on one shaft for one-pass hole drilling. For sharpness, I have found that solid carbide bits are perfect for pinblock drilling, and they stay perfectly sharp for several pinblocks. ( everybody recognizes the superiority of carbide tipped saw blades, but few will actually buy a solid carbide drill bit.) Drill only with very sharp bits. If you cannot perfectly machine sharpen your own bits, buy several of the best bits and/or reamers you can, send them out and have them done right. They are totally different, and vastly better, than the gold colored (titanium nitride coating) bits at Walmart or Harbor Freight. I can sharpen and split points on my own bits with a sharpener I have that (used) cost me over $500.00, but most people do not have one. Get your bits from a local machinery supply dealer. These companies supply precision machine shops. Go look in their catalogs to see what they can get for you. ( look under; machine shop supplies) If there is nothing in your area, try McMaster Carr, or MSC (1-800-645-7270) They have all the tooling necessary to set up an aircraft factory. For just good bits, Cleveland Twist Drill (888-434-8665), or Precision Twist drill, . (don't have their number) - All these suppliers have online addresses. At 888-434-8665 you can get technical help to find the right "fit" of tooling for your technique and material. Size is a big deal, but results can vary with technique. There are four standard sizes of drill between the 17/64 and 6.8 mm pinblock drills mentioned by one poster. 17/64 = .2656" 6.75mm = .2657" H = .2660" 6.8mm=.2677" Get a drill size chart and experiment for torque desired with a particular set of tuning pins in a particular pinblock with a particular way of drilling. Top quality drills are closer to the size they say they are, and the slightly different sized holes they drill can make a significant difference in torque. If you use a hand drill, even with a "bubble", your hole could easily be up to ten-thousandths larger than the drill. I suggest you rig up some sort of jig to either drill the block after it is finally attached to the plate, or that you mark the holes and drill in a jig on a drill press, for improved consistency. In the end, jigs and better drill bits and more precise drilling machines are only to give you an advantage to replace skills and experience you don't have. A hundred years ago they were drilling by hand with brace and bit, walking over to a grinding wheel and sharpening the bit by hand and eye, and they got consistently good results. It isn't rocket science, and if you drill five or ten blocks a day, like they did, you can dispense with most of the above information. We have to use better technology just to do as well. Good luck. Bill Simon Phoenix
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