The claw took me about a day to build, and cost me nothing to build. However, since it is relatively unlikely that you will have the required pneumatic parts ready, so it will probably cost you a bit more.
Step 1: Materials
- Pneumatic cylinder- make sure it has a large diameter, something over 2 inches is probably best. stroke length around 4 inches, and pressure handling of 110psi to be safe. check ebay. mine is a bimba stainless steel 2in diameter, 4 in stroke length.
- Plywood - i used 1/2 inch, 4ply for the gripper parts, and some thicker, 10ply? dense hardwood plywood i had laying around. the thicker stuff is mechanically indestructible. got the thinner stuff for a different project at lowes.
- 4 way poppet valve - i got mine for free, mine is a bosh rexroth type 840. check ebay. they are made specifically to extend and retract pneumatic cylinders.
-pneumatic tubing. size depends on your valve.
-pneumatic fittings: three hose barbs, depending on your tubing size. one coupling, one pneumatic quick connect.
-electrical switch and some wire.
- random (thick (3/8)) nuts, bolts and wood screws.
- 13.74g of common sense