Reddit reviews STEPPERONLINE 50:1 Nema 17 Geared Stepper Motor L=39mm High Precision Planetary Gearbox for 3D Printer DIY CNC
We found 1 Reddit comments about STEPPERONLINE 50:1 Nema 17 Geared Stepper Motor L=39mm High Precision Planetary Gearbox for 3D Printer DIY CNC. Here are the top ones, ranked by their Reddit score.
High accuracy, high efficiencyNema 17 stepper motor 39mm length48.3mm Planetary gearbox of 50:1 gear ratioMoment Torque 25Nm(3540oz.in) & Max Torque 15Nm(2124oz.in)Rated current 1.68A & Rated voltage 2.7V
Buy a swagelok valve from here (paying full price is for suckers and these guys ship faster than Swagelok anyways). For reference you can get a brand new swagelok for less than $40 from this site. Just compare the part number to the swagelok website to check seal/o ring materials.
Buy a high torque stepper motor and hook it up to the valve. You will also need a stepper motor driver that can deliver sufficient amperage. This is pretty much the simplest/cheapest way to get 150 in-lbs of torque delivered to the valve. Theoretically you'd only need about 50 but better safe than sorry.
This is the cheapest and simplest way to get what you want. If you already have gear for pneumatic control (air tank, solenoids, regulator, etc) pneumatic might be cheaper but you also don't get fine position control with pneumatic so take that as you will.