Tuesday, May 13, 2014

More Drill Size Questions...Stop the insanity!

What drill size is preferred by lead players? Similar questions to this seem to get asked often. So, here goes: GR always says....depends on the length of the throat (as far as the resistance one would feel). 30 can feel free blowing compared to others with a 27. Actually GR would tell you to grab a fluid dynamics formula book.

You can't just look at the throat hole size, it's length as well. Therefore a 28 hole and 19 hole can have the same resistance given the length of the 19 is very long and 28 .05". So what else happens! Open your thinking.

As the throat gets bigger it gets longer.....backbore gets shorter, and cup volume is reduced. You need to look at the total resistance of backbore and throat. We have a reverse engineering program written for calculating this for any mouthpiece and any leadpipe. We have a few, over 1000 on file. Remember each is going to be different due to any alterations, age, or manufacturing.

 Monette C12 Throat .166", Total resistance of backbore and throat = 12.1303, Throat resistance 5.7945 Backbore resistance 6.3358

 #1-Bach #10 BB Throat .144 (#27), Total resistance of backbore and throat = 12.86225619, Throat resistance .84856 Backbore resistance 12.01369

 #2-Bach #10 BB Throat .144 (#27), Total resistance of backbore and throat = 13.9536, Throat resistance 2.4244 Backbore resistance 16.37833 (Longer throat shallower cup and longer backbore)

This is an older BB that was suppose to be so great an old 3C that was suppose to play awesome similar to Charlie Davis 3CBB Bach 87 BB Throat .157", Total resistance of backbore and throat = 6.62019, Throat resistance .6373 Backbore resistance 5.9828511

 Reeves 6924 Throat .143", Total resistance of backbore and throat = 20.1828122, Throat resistance 6.11957 Backbore resistance 14.06323

 Maynard very old Throat .1516", Total resistance of backbore and throat = 14.80962, Throat resistance 4.343244 Backbore resistance 10.46638

 Kanstul 117 Throat .1456", Total resistance of backbore and throat = 14.29828, Throat resistance 3.524625 Backbore resistance 10.77366

 Callet DT-10, Throat .1415", Total resistance of backbore and throat = 26.44187, Throat resistance 10.66559944 Backbore resistance 15.77628

 Brian Scriver www.grmouthpieces.com

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