This is a simple key duplicator for older automotive two sided keys.  It is designed to fit a ryobi or dremmel multi tool by screwing the tool into the cutter using the accessory threads. The cutting wheel is a 25mm wheel commonly available. Assemble with m4 hardware.  Align the reference key on the left and the new key on the right.  The key guide and cutting wheel must align before you cut.  Use the key guide to set the depth of the cutting wheel against a portion of the key that does not get cut.  Place both keys in the holders at identical depths.  Cut from left to right.  This is a simple tool to cut spare keys, hidden keys, or any key that you have the capability to program.  I designed it for my older Toyota keys but others should work just fine.