Here is a rather long and arduous video showing how I do it. What I didn't show was I stuff a piece of paper towel in the hole in my dust collector box and the groove of the gun drill otherwise chips will blow out the groove of the gun drill in spite of the vacuum due to the air pressure.
This is just how I do things. Not sure if it's right or wrong but it seems to make sense and work. Actually I have modified a couple process' since then. I now use 16 TPI to make it easier as my thread mill will engage on any mark without cross threading. With 14 you have to engage on a mark the same as you started wither odd or even. With 16 you can't screw it up as you have 16 marks that will work so you can engage it just about anywhere on a mark or half mark. I also cut the forstner bit hole before threading it works better and won't chip off your last thread. But it's been a few years since I made this. I found facing the wood perpendicular to the core is really important if you have even a .001" out of perpendicular it will noticeably warp your a joint. Also torque is critical of that joint to not deform it as once the epoxy is there it's a lot slicker and easy to over tighten. I mark it dry and stop there wet pretty closely.
How I core my forearm wood for Coos Cues Please like and subscribe to my channel!
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