From the pic where you are drilling, it looks like you do the same little trick that I do, but I don't think you mentioned it George.
Before drilling, use the tube and make a mark on the drill bit. Then you know when to expect the drill to exit the other end and you can take that little bit more care.
Great tutorial BTW:biggrin:
Nah, just us cleverish ones:biggrin:
I started to make one several years ago and then realized that ANY word description would make it seem more complicated that it is. Below are three pictures that show the process. The first one is the first picture on this forum of TBC. IN fact TBC didn't have a name at that time and I referred to the first ones as "Mandrelless", i.e. "without a mandrel". Two fellows, Frank, aka Rifleman and JohnnyCNC both told me of a method they had heard of that did not use mandrels. I was having a specific problem with mandrels at that time.The article is no longer acessable