Toy model of a guillotine. This was printed with Overture matte PLA on my Qidi X-Smart. 3mf file will illustrate supports and tolerances, etc. Print the file - Guillotine_pin.stl - 2x. Be careful pushing the 2 pins into the holes of the shear lentil and shear itself. Mine was tight, and worked great. 

I used a 1.5x73 mm length metal rod for plunger. I put small beads of solder on one end so the rod dosen't pull out from the shear lentil. One can use different solutions for the mechanics.

Enjoy.