halvor
a most elusive fish
Brilliant! ThanksThe brush is bored out in order to keep it light. The depth is therefore whatever you want it to be!! - What I will do is fill the void with hot glue or resin before sending it out to give a shelf for the brush base setting. So the final hole depth will be around 20-22mm leaving plenty of scope for setting the knot to your desired depth.
you gotta love those jumping razor cases