Shaping the Cutters
Here are the steps I followed to grind the bolt cutters into the proper shape:
Disassembly. Two bolts and the center retaining washer. There is a little round roller bearing that keeps the jaws separated and is a loose fit - be sure not to lose this!
The First Jaws - The Front Rivet Jaw and the "Anvil" Jaw
Grinding to shape - measured at 1/4" and this fits perfectly into the rivet groove on the inside of the trunion. The process is more like "grind - test fit - grind again - test fit"... you get the idea:
Ground to rough shape. Preparing to get the final "fit" - I marked the jaw with a welder's soapstone marker (the white film):
Now to grind:
The location of the jaws are adjustable - you can use the set screw to dial in the final location of the jaws when clamped. This proved invaluable for the final adjustment to get the rivet pressure correct:
Note the jaws are now at a different angle - and distance apart - when clamped:
The "Anvil" Jaw
This is the jaw that sits against the bucking brace I made for the rivet head, similar to plinker's rivet jig. The brace is simply a piece of 1/4" metal to which I dremelled a concave divot. The head of the rivet sits within this "cup".
The anvil needs to be flattened more. The entire cutter section needs to be removed. I first attempted with this amount of material:
... and it cut into the bucking brace. I need to make a new one now. The anvil needs to be cut down to probably about the thickness of the rivet head, which means all of the sloped "cutter" section needs to be ground down. Not a big problem, but my brace was destroyed:
The Second Jaw - Right Middle Rivet
This jaw is for the upper rivet on the right side. The right side is the safety selector side.
NOTE: The jaws need to touch the rear upper rivets from the top. They cannot be inserted from the front because they will not have the strength to work, due to the distance involved. Thus the need to approach from the TOP of the trunion. Look at my pics on the boltcutter page of the failed attempt to approach from the front...
Shaped, ready to test:
This is the angle I used... see how the trunion is vertical in the vise. If this were the real thing, the receiver would be ABOVE the vise:
The Third Jaw - Left Middle Rivet
This jaw is for the upper rivet on the left side (the ejector side) that has the extra trunion material around it.
Preparing for the left rear trunion. This one made me nervous, there was quite a bit I had to take out:
Close-up of the shape:
Here's a pic of all three of the modified jaws: