The attached PDF file are the drawings made to fabricate gas check makers.
The dimensions are" neat" there are not any dimensional clearance in the parts.
The cup making punch should be made first and the hollow disc cutting punch made next.
The disc cutting hollow punch is made from water harding drill rod. This is the only hardened part. After harding the hollow punch can be annealed in an oven at 500 degrees with the part at temperature for one hour.
The bodyof the check maker was made from 4130 bar stock left over from another project. Any steel should work for the body.
The base was made from aluminum again left over from another project.
The body is machined once the two punches are finished so the bores in the body can ge cut to the dimensions of the two punches.
Keeping the bores concentric is important and keeping the clearances close is also desirable.
The gas check makers are pushed with a small press from Harbor Freight. The same small press is also used to installed the gas checks by pushing thru an upside down Lee push thru sizing die.
The soda can material will not take much axial stress when pushed thru the Lee sizer. A little Imperial sizing wax will lube the check and not stress the check to a point of tearing. as it is being installed on the bullet.
These punches have work well for my use, others milage may vary.
The dimensions were derived from the data furnished by Ed Smith in his PDF file.
bstone5