Lever for the Operant Conditioning Chamber.
First look at the Operant Conditioning Chamber: http://www.thingiverse.com/thing:1226076
Print the parts using PLA because it is a non-toxic material. A layer height of 0.2 mm is recommended. Most parts can be printed with a 20% fill density. However, “bumper.stl” must be printed with 100% fill density. This part counterbalances the weight of the lever and must be heavy. No support material in necessary.
You will need also the following materials:
1 Stainless steel metal plate (gauge no. 16). I like to use a steel lever because rats occasionally chew the lever. If this is not a problem in your application, you could print the file "Lever.stl" and use a PLA lever. My recommendation is to ask a CNC cutter service to make a stainless steel plate for you. The dimensions can be found in the image inside the Plate.zip file. Note that all the measures are in millimeters.
1 Snap action switch. The “switch.stl” file was designed specifically to hold a Honeywell 311SM4-T switch. These switches are very precise and the lever was calibrated using these switches. I got them from Mouser Electronics (part # 785-311SM4-T). www.mouser.com.
2 – # 4 x 1/2 in. Metal Flat Phillips Screw. These screws attach the section with the switch to the body of the lever enclosure.
1 - M3 x 20 mm Brass Threaded Stand-Off Hex Screw Pillars with Nut. It is used to hold the metal lever in place.
6 - M3 x 10 mm Screws. Two scres keep the lever attached to the panel of the chamber. Two screws are used to adjust the length of the lever, and one more is required to limit the vertical movement of the lever.
E6000 Glue. This is necessary to attach the part in the "bumper.stl" file to the actual lever.
Use the images to assemble the lever. 3D printed parts are blue, metal parts (metal plate and stand off) are white, screws are black, and the switch is brown.