The v block in the picture is to take the transfer punches PeteI have to ask if you turn your blanks round and parallel before squaring the ends? Reason for asking is if the blank isn't drilled dead centre and perfectly square or round, the ends may not finish off square to the tube. I use a transfer punch (aka disassembly tool) clamped in the V block for the tubed blank to slide on. Ensures a squared blank every time even with irregular blanks like antler.
Pete