http://www.rockofages.com/precision/oem.html

Try the above company. We buy from them and specify inserts. If you query
them they may tell you what you need to know and what or how they install
inserts.
lg
no neat sig line

"Tim Killian" wrote in message
...
I need to add some 1/4-20 threaded, blind holes to a 4" thick granite
surface plate, and I found a diamond core drill that will make the holes.
What is the best type of thread insert to use for this application?