I used the shoulder screw and spring from a cleco side clamp.
I used a lathe to make something similar to the cleco flange.
I tapped a 1/2-13 thread thru 3/8 x 3/4 cold rolled steel bar.
I also welded a 1/2-13 nut onto the bar for extra threads.
Two 1/8 dowels are force fit into bottom jaw to prevent rotation much like that on the original cleco spring clamp.
The 1/2-13 drill busings are available in many sizes.
The cold rolled steel top jaw have the 1/8 holes reamed slightly larger.
The jig is not used on nose ribs, but the picture contrast is better.
