I agree with Karl...I prefer a single accurate pass. I use a chiller because I have one. Compressed air might be fine alone, as its pretty amazing how effective a simple stream of air is at drawing heat away from the bit.
I tried double drilling in numerous permutations, and I did not find it to be an improvement, in any type block. However, the reason has more to do with my machinery than the concept. All of this discussion is machinery and tooling dependent, so when someone reads these posts they should keep that "machinery & tooling dependent" attribute in the front of their minds.
When Ron described his double drilling, he only realized after some time of advertising the technique, that the slop in his beat drill press quill was an essential attribute of the success he experienced. As well, he also either did not realize or perhaps communicate how important the very long bit he welded up was to the effectiveness of his set up. Why?...the sloppy quill and long bit allowed the slop in the system to "find" the 1st pass hole. A more accurate machine setup, would force its "opinion" into the 2nd pass, giving a rather inconsistent sized hole.
Looking at Terry's fine system, I'm pretty sure he has achieved the "let the machinery conform to the location of the first pass itself" attribute. As he moves the floating drill head, I do not see him locking it down for the plunge. The bearing setup on the ceiling, the distance from the bearing tracks to the head help allow the necessary give in the system, and the drill head itself is a light duty Jet or Grizzly type head (I believe). All these attributes allow the 2nd pass to better follow the 1st pass hole.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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Original Message:
Sent: 11-28-2018 08:57
From: Karl Roeder
Subject: Air cooling drill bit / tuning pin angle
I don't like two pass drilling. Probably because I'm not good at it. How do you center the second hole accurately? The pianotek chiller is admittedly pricey but a similar tool can be found on amazon for as little as $49. If I'm already using the compressor to blow air at the bit it doesn't take much additional effort to add in the chiller. Maybe if I used delignit or other multi-lam material I'd learn how to get better at two step drilling but for now it's just not worth the extra time and frustration.
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Karl Roeder
Pompano Beach FL
Original Message:
Sent: 11-26-2018 08:28
From: David Chadwick
Subject: Air cooling drill bit / tuning pin angle
Greetings,
I am trying to find a flexible air cooling system for my drill press. A search mostly shows wet systems for milling and lathe machines. Any suggestions where I can find a selection is greatly appreciated.
Also, I have been drilling tuning pin holes on a 7 degree, as prescribed in the Reblitz book, for many years and I'm not to pleased with the lower coil running down the pin angle. Do any of you go to that angle or a lesser angle maybe 5 degree perhaps?
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David Chadwick
Newark OH
740-610-6695
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