Enlarging existing bridge pin holes

[Ron Nossaman]

> I am repining a bridge and because the bichords are a strange in between
> size (about 9 1/2), I need to enlarge the holes to accommodate a #10
> pin.  I have not had much luck doing this in the past in a clean way and
> am wondering how others approach this.  My thought is to reinforce the
> bridge cap with a clear coat of epoxy first before drilling it out,
> reaming out any excess that might create large globs inside the hole
> before it sets up.  Any thoughts on this?  And what is the best way to
> approach redrilling an existing hole: high speed, low speed, by hand?
> 
> David Love


I haven't done this a lot, but I've had the best luck hand drilling 
with a modified drill bit. With a diamond whetstone, I ground the 
cutting edges parallel to the length of the drill. This makes a 
scraping cutter that doesn't grab and pull itself into the hole like 
a standard drill bit. Or you could order a spiral reamer of the 
appropriate size.

  http://www.trianglereamer.com/highspeedsteel_reamers2.html