Miniture Piston Keychain has been modeled to have very low clean up required by adding supports & radii. I also separated the bigend to aid printing plus I think the little bolts give it a cool mechanical feel.Parts Required: 1) 2x M3 x 10mm socket head cap screws. 2) 2x M3 nuts.All should be available from a hardware store or fastening supply store.Print the Piston Body, Conrod & Bigend with the following settings:Infill 100% Layer Height 0.2mm Number of shells 1 Feedrate 40 mm/s Travel Feedrate 80 mm/s Print Temprature 230cPrinted the Roll Pin with the following settings:Infill 100% Layer Height 0.1mm Number of shells 0 Feedrate 40 mm/s Travel Feedrate 80 mm/s Print Temprature 230cAssembly:1) Simply assemble the conrod bigend using the M3 nuts & bolts refering to the photos as a guide. The bolt holes shouldn't need reaming as they are slightly oversized. 2) Ream out the piston body & smallend slightly with your 3mm hex key. 3) Pop the smallend of the conrod into the piston body making sure the holes line up. 4) Push the roll pin into the piston body as far as you can by hand. 5) Use a pin punch to carefully tap the roll pin into it's recess.Enjoy!