i would like to know what pneumatic parts are needed to make a piston cycle fast. for example if i had a 2 way valve and a one way spring return piston and i hold the valve the piston goes out. if i were to release the valve it returns to home and i would have to repress the valve to create the motion again. but what i want to create is a piston that was "automatic" what pneumatic parts would i need and what website can i learn from. kinda like if i wanted to make a pneumatic reciprocating saw.