Best method/Reamer Type to Repair Broken Casting

Hi,
I have a cast iron bushing block for an old American Tool Works lathe that I need to repair. The item has a chunk missing with the fracture going in between a bolt hole and a taper pin hole (See attached pic). I don't have the broken piece, unfortunately. My plan is to fill in the missing area with braze and remachine it as required. Drilling/counterboring the bolt hole should be pretty straight forward - but I'm a bit concerned about the taper pin hole. I can try brazing around an inserted pin covered in graphite, or just fill and redrill/ream the pin hole. About 270 degrees of the original pin grip area remains. My question is, if I drill and ream the taper pin hole, what flute type would be best considering the two metals?
Thanks!

I do repairs like that by silver brazing a piece of cast iron into a space made by milling the fractured surface. That method takes away the problem of simultaneously reaming brass and cast iron.

Larry

Thanks for the reply Larry!
For this situation, would you just mill-out both broken holes and then re-drill/ream them once the block was soldered in place? Because the taper pin is for locating the block I'm concerned about getting it in exactly the right spot and don't want to enlarge the hole any more than I have to.

I don't see the need for the tapered pin. I would leave it out and just tighten the two screws with the carriage cranked all the way to the right end to be sure the bracket is lined up so the lead screw and feed shaft do not bind.

Larry

Even a somewhat crude low production lathe like my 7100 Lb Greaves Klusman has tongue and groove location for such. The up and down position being the main concern

if you are going to braze the piece, grind the dowel pin out completely and fill it with braze. That ends the concern of reaming the dowel pin in a bi metal material. Then as Larry suggested, just leave that dowel pin out.

Hadn't really thought about just leaving the pin out. Thanks for the ideas everyone!

The tapered pin is a dowel and dowels determine location. Threaded fasteners clamp the parts together. The dowel needs to be there to assure reassembly in the same relative position. Since the area is flat you clould align it with a steel dowel and clamp everything in place. Then braze a repair piece in place with the dowel removed. The dowel hole could be cut oversize and preserve the original location. I'm sure it would work, maybe a long time if you just leave it out, but, is it right? These were quality machines and deserve a quality repair.