I've got a Gizmo articulated hollowing rig. Now my largest boring bars are 3/4" diameter which limits how deep I can hollow. I'd like to make a a larger diameter boring bar to use with deeper vessels.

I'm thinking to make one similar to the Jumbo Boring Bar that Lyle Jamieson sells...1.125" diameter bar with a 3/4" diameter tenon on one end to fit into the Gizmo and a hole bored into the other end to accept one of Lyle's bent swivel cutter assemblies. I'd buy one from Lyle, except the tenon on his is too short for the holder on the Gizmo.

My question is what grade of steel to use for the bar. Anyone out there care to give input? This site discusses steel properties: https://www.onlinemetals.com/product...steelguide.cfm It seems like Alloy 1018 (cold rolled mild steel) or 1144 (stress proof) are the likely candidates.

So I'd appreciate any input people have on grade of steel to use and any other considerations in making a large boring bar.

Dave