How do I determine what gears to use on a table mounted reciprocating device?

I am making a multi-function reciprocating device that will cut/crush many small materials from  thin wood to aluminum/sheetmetal. Mounted on a portable table I have a small 120V motor for my power. I want to design my own drive system using available gears/sprockets, but I am not sure where to start or how to determine which gears to use to achieve my desired output SPM. I could use some advice and pointers on calculating gear size/teeth, which ones will mesh properly, and what type of gears would be best.

Shrty (author) 7 years ago
Thanks for the reply guys. Hadnt thought about possible lockups. Just browsed the link Rick *Thanks* but will dig into it deeper when it gets too hot to work outside and get back with you asap,,,,,,,
rickharris7 years ago
http://www.vintageprojects.com/machine-shop/power-hacksaw-plans.html

has information on such a saw.

Belt drive is common for reciprocating saws ets and is more flexible than gears (and a LOT cheaper).
Another good reason to use belt drive is if the machine locks up then the belts usually will slip where as gears won's slip and you may damage your machine.