1 Insert 
This insert is made of phenolic, with a barrel type design.  Threads are 1/2-20, and the barrel is used for alignment.  The .280 thru hole is designed for you to bore and tap once installed.

Overall Length = 1.25"
Backside Threads = 1/2"-20
Threads Length = .741"
Alignment Shoulder Diameter = .509"
Alignment Shoulder Length = .790"
Thru Hole Diameter = .234"
Drill 3/8" Hole - 1.50" Deep
Bore Hole to .465 - 1.50" Deep using Boring Bar
Tap Hole with 1/2"-20 Tap to depth
Counterbore hole .750" deep with boring bar using NON-Threaded side of insert for your gage.
Apply insert with Epoxy - Let Dry - Drill / Bore / Tap ID to desired size.