Author: shmuelyosef
Date: 2017-05-21 04:39
Your experience on tapers is very different from my observations. A typical Morse taper has a substantially higher angle taper than any barrel I have observed. Here is a table:
http://littlemachineshop.com/reference/tapers.php
Note that these are "half-angles" or angles from center. A typical barrel has about 30mm or so of actual clarinet bore. At a half-angle of 1.4 degrees (smallest of the Morse tapers), the diameter change using such a taper would be:
2 * SIN( 1.4 degrees) * 30mm = 0.73mm or 1.47mm (0.058")
The most extreme barrel that I have measured has a diameter change (over the bore) of 0.28mm in diameter. This is a half-angle of 0.27 degrees...a factor of 5 smaller. The Moennig taper (generally assumed to be from 0.589" to 0.580") works out to about 0.22 degrees for a 66mm barrel.
Ferrees Tool company sells a clarinet barrel reamer but I haven't been able to get them to tell me what the taper angle is...Curtis Ferree just said:
"Very slight tapper pretty much fits everything. Built this tool about 18 years ago with Charlie Bay and it`s the same to this day and the only one we have for this kind of work"
I have not found another commercially available tool, so I suspect that this is what most folks are using if they are reaming. It is hard to set a tool-slide to a very small taper with any accuracy, although it can be done (after a dozen test cuts!). I do know that a couple of shops have bought custom reamers (e.g. Muncy Winds uses a lower angle taper, as does the makers of the Chadash barrel). Some vendors just cut multiple straight bores and then finish by hand. For example, if you want 0.1mm(radius) over 30mm length, you just move the cross-slide 0.01mm every time you crank 3mm on the cross-slide. A 0.02mm step will sand out and polish up nicely. This is nice for one-offs, or OK if you have a numerically controlled (NC) lathe, but otherwise not so great for production. All of these will require some hand-finishing, so there will always be variability, but it should be controllable to much less than 0.1mm in the final diameter.
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The Clarinet BBoard
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