wrote:

Could use a forstner bit to enlarge the hole, glue in a good
hardwood
dowel, and start over, or just fill it with a "filled epoxy". For a
"filled epoxy" I'd use hardwood sawdust (or better yet, "wood flour"
made from hardwood and a #40 belt sander) and slow epoxy resin.

Right idea, BUT wrong filler.

Saw dust or wood flour simply soak up resin, but add no strength.

Use micro-balloons for filler.

They are low cost and the epoxy likes them.

An alternate is to buy fairing putty such as:

http://www.systemthree.com/p_st_quikfair.asp

I'd probably drill a hole with a 1" forstner bit the length of the
metal insert + 1/4".

Fill hole in two (2) passes.

Anything more than about 3/4" thick pour has a chance of "kicking"
since curing is an exothermic process.

NBD other than you lose some material and re-drilling hole to clean
out is a PITA.

DAMHIKT.

Correctly done, resulting repair will be "strong like bull".

Have fun.

Lew