Gidday Lee, to add to the good advise you have already received this is what I do if the “pin” hole is too big.
I use CA adhesive to fit an appropriate sized piece of leftover sprue into the hole, cut, and file it flush…
…then drill and using my 2-56 tap, thread the hole.
If required here’s a link to a current thread on tapping 2-53 threads.
http://cs.trains.com/mrr/f/88/t/212215.aspx
Cheers, the Bear.