In this picture you can see the softer marrow like part of the anlter
Using a 1/4" drill bit, I let the bit follow the softer part of the antler through and out the end of the base. Thus leaving a nice chaneel in the flat side of the mouth piece
Using the end of the bit I finish off the channel leaving 1/8" or so of the antler flat around the edges of the mouth piece
Turn the piece around in the vice so the base is facing me
Using a 1/2" bit I fallow and wallow out the first hole half way back through the base. Thus crating two chambers. A smaller chamber at the mouthpiece end of the call and a larger funneling chamber at the other or base end of the call. Sort of like a megaphone shape inside
Finished inside
Using a rattail file I file off any burrs or sharp edges left by the bits
The flat part of the mouth piece should start flat at the call end of the mouth piece and drop off slightly or slop downwards towards the tip of the mouth piece. This is where you will fine tune your call by the angles on the flats of the mouth piece.
I find,,, A larger gradually sloping mouth piece will be loud and very raspy. A mouth piece that barley slopes at all will be sharp and high pitched.
In other words,,, the distance and slope between the reed and the flat part of the mouth piece of the call will determine the sound you achieve.
Playing around with that aspect takes time and patients,,, you must go slow and try it every little it to see if it where you want it.
With a little practice this call can make a crow "caw" easily and makes very good coyote howls and Challange barks.
I buy this artificialreed material that is sold for making duck calls. I get it off a internet auction site and it is cheap and you can make more calls than you'll ever need.
I cut enough off to the shape of the mouth piece and leave enough at the tail end to fold up on the back part of the call at the mouth pieces base.