I recently came across an article in issue 157 about making a wobble broaching holder by Jock Miller. Has anyone on the forum made this? I did make Michael Cox's rotary broaching tool and this done a great job but I now need something more industrial so that I can purchase commercial broaches. Jocks plan shows the broach holder 8mm, do you think it could be drilled half inch as this seems to be the common size for commercial broaches also the steel he recommends is Aisi 4340 or 4140, the steel supplier I use suggest it is now en 24T. Any help would be appreciated. If it was not possible to drill the tool holder to half inch do you think Harold Hall's advanced grinding rest would let me grind the cutters. From HSS I made one of these but never used it.

JasonB thanks. I will have a go at trying to grind the cutters, As I said I made the Harald Hall advanced tool and cutter grinding rest but never linked it up to a grinder. My question is does anyone think this would do? Also the steel Jock recommends is Aisi 4340 or 4140 is this the same as en 24 T. Any help appreciated.

Thanks very much Jason.

Sorry for the delay, not very good on the computer so always have to wait for someone to assist.