How can I make a pair of bolt jaw tongs to hold round stock without a swage block? I've made a few tongs and know a fair bit, but the jaws are frustrating me right now.

Use the Cutting plate where it meets the anvil face as a V block if you haven't got a swage

Get the jaws hot, grip your bar sized for the bolt, place the clamped piece on the cutting plate abutting the face of the anvil with the opening of the jaws at 45 degrees so each side contacts a solid face and coax the edges of the jaws to grip the bar, keeping it in alignment, then finish off rolling them on the anvil face. .

Or you could use a block in the hardie hole to the same effect.

Take a nice fat piece of steel, get it up to yellow, lay it at a 45 on one of the edges on your anvil, then pound on it 'till it's a swege.

if you can weld you can make a mini swedge block that can fit in your hardie hole out of a piece of angle iron.

V-jaw tongs hold rounds far better than round-jaws do.

Nakedanvil's right. I found that out the hard way after making a set of round jawed bolt tongs. They work, but the 2nd pair I made had a v jaw (at Nakedanvil's suggestion) and they grip much better overall.

V-jaw tongs hold rounds far better than round-jaws do.

They are right........ And a vise will do for shaping or as stated the anvil