Make a scroll saw! (using only upcycled/free materials)

Step 6 Captain hook

The idea is to beat the metal rod into a hook shape.  That way it will turn the rotary motion of the drill into a reciprocating motion for the saw.  It works the same way as the crankshaft in a car engine.

Notice mine the metal goes past center after the hook.  The purpose of that is to try and counterbalance the metal on the other side to reduce vibration.  A better way might even be to make an identical hook on the other side so you're sure they are the same size.  (Less like a "?" and more like an "S".)

This was the hardest step for me. If you have a machinist vice or torch or bender this would be a whole lot easier. I just grabbed a hammer and pipe wrench and wolloped on the thing till it looked reasonable.  (Not too scientific, I know.)

Also, I should mention that I had to redo my first hook.  The more exaggerated the bend, the further your blade will travel.  My first attempt was over 2" and the blade traveled so far it was physically impossible to cut anything with.  I was able to get it down to 1" but even that is a little excessive.  1/2" to 3/4" is probably about right.