"Karl Townsend" wrote in message
...
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel.
The
drills mount in a one inch bore.

Karl

How about using three guide hole blocks instead of one challengingly
long hole?

You could make a 1.75" box channel from flat stock with your 1" holes
in the end plates, and if necessary add one or more blocks within. If
sliding a drill rod through shows they aren't aligned, cut down the
inner one and locate with setscrews.

A 1.75" box channel made of 0.375" ground flat stock might be good
enough with just end plates, if you drill the dowel pin holes
accurately enough.
jsw