Thread: Bernerd Model 34 4 Jaw Chuck - Face plate bolts?

That particular backing plate was given, as a rough casting, by me for free to the previous owner with the rear register and thread done only, the machining of the rest was abandoned as it had a small casting flaw in the threaded area which meant I couldn't sell it. The trouble with the old castings was they were cast with a core which left a hole to save on boring time. As the core always moves a little when they pore it, you have to use the cole hole as the datum for the thread, this is necessary because this is the only way to guarantee you will clear the cast iron scale when threading and machining the rear register. The unfortunate bi-product of doing it this way is it is rarely central to the overall casting and requires quite a lot of machining to true up the rough cast faces.
Because of the reject rate with this type they were discontinued in favour of machining from bar stock. So long as you don't disturb the rear register on the hob, you should be able to machine the front and rear faces so they will all be concentric to the register and thread and therefor in balance. I hope my phone call helped, if not let me know what you need.
Mal

Thanks Mal,
It'll probably be next weekend or so when I get chance to have a look again but I'll let you know how I get on and give you a shout if I get stuck!

Thanks for the call earlier.


Thx
J