those pesky nose bolts

[Gene Nelson]

>
> At tear down, I drill two locator holes through the plate, into the rim. 
> One in the treble, and one in the tail. I use these holes to index plate 
> and board when I locate bridges, to index the soundboard when I locate 
> nose bolt holes, and when I glue it in. Again with the plate to locate the 
> pinblock. I find I need the soundboard assembly dried down to the same 
> level for everything from ribbing to final installation unless I want 
> surprises along the way. With the nose bolts out, I drill the pilot hole 
> they're in clear through the bottom of the beams. Then, locating the 
> appropriately dried soundboard on the two pins and clamping the board down 
> onto the rim in a few places, I transfer punch the nose bolt hole 
> locations on the soundboard from underneath. This works better for me than 
> anything else I've tried, and I still don't get perfect centering. If 
> there's a better way that doesn't involve yet another level of psychosis 
> or the ability to slide drilled holes to other locations, I'd like to hear 
> it too. Actually, If there's a way to slide drilled holes, that's the one 
> I want to hear about first.
> Ron N

I did index the board to the plate and inner rim but failed to control mc 
through at least this particular part of the process.
Drilling from the bottom sounds like a solution - what do you do when they 
are threaded into the belly rail?
Del's idea about the die grinder was the solution - no splinters but the 
finish melted just a bit on the edge of the hole - not really noticeable and 
it will work and look good - a nice round elongated hole - not egg shaped.
Do you think that in the factory, some of those bolts were persuaded into 
plate struts with a little more than careful alignment?
Thanks everyone for the ideas and I will be looking out for those mobile 
black holes.
Gene