We assembled version 3 of the mechanical shear today and guess what...We don't NEED no stinking hydraulics! Version one, see the link below, used a cam to operate a lever shear with the 3 flat wires passing through holes in carbide inserts and the inserts would be moved against each other. Version
2 replaced the cam with a cam follower in eccentric. Version 3 doubled the ratio from the follower to the fulcrum and uses square carbides in a standard shearing action. Much to our surprise, we can turn the sprocket by hand without even a rag, and cut the wire! Maybe 10 foot-pounds? Well, that changes everything! Version 1 would cut the wire with a 14" pipe wrench for leverage, we had to brace the apron on the machine worrying about the casting flexing. Now I'm thinking we could use an air cylinder on version 4.Thanks for the great discussion and brain candy! Another thing that happened is that version 3 is really version twenty something. We used Solidworks exclusively to design and dismiss a lot of ideas. Prime considerations were decreasing down-time to change carbides, use standard $6 carbides rather that $16 custom made inserts that can be flipped once, the squares have 8 cutting edges each. The other consideration was cut quality, imagine the cut from inside a hole. The squares leave a perfect milled looking edge with no burr. Another 20-30 years and I have it perfected!