Pocket Transmission Assembly Instructions

Important Notes:

Use a dab of Loctite on all your screws, so they don't come loose when you're running your transmission.
You should have all the hardware you need in the packet you were handed. However, if you find you need an extra nut or screw, you can find extras in the 3D printer room (around the corner from the laser cutters).

Assembling the Gears

Each gear is cut twice and the two pieces are screwed together so that they are 1/4 inch thick. When assembling the gears, slide them onto the hex shaft first. Then use two 3/8 inch screws to fasten them together. This way you are assured that they can move along the shaft without binding.

Assembling the Collar

The collar uses eight 1/2 inch screws that act as "teeth" to mesh with the differential gears. Four of these screws should be pointing one way, and the other four the other way. Alternate the directions as you go around the circle. In order to keep the nuts from coming loose use should apply one tiny drop of Loctite thread locker to the screw shaft before tightening the nut. Loctite is available in the Digital Fabrication Lab (the room with the 3D printers, around the corner from the laser cutters.)

Assembling the Mid-Panel

Insert two gear holds (L-shaped brackets) into the mid-panel to hold the small differential gear against the mid panel. Secure the gear holds with 1/4 inch screws.

Insert the input shaft (2 inch hex standoff) into the mid-panel; secure it with a washer and 1/4 inch screw on the right side of the panel.

Hold the small differential gear in place under the gear holds while inserting the output shaft (4 inch hex standoff) into the mid-panel. Then, secure the shaft with a washer and 1/4 inch screw on the left side of the panel.

Insert the lay shaft (3 inch hex standoff) into the mid-panel.

Adding the Left Panel

Attach the 3/4 inch #4 nylon spacer (the skinny one) to the handle using a 1 inch #4 screw and a nylon locknut. You will need to use a screwdriver and pliers for this. Don't tighten the locknut all the way; you want the spacer to be spin freely.

Insert the front and back panels into the left panel, then insert the left, front, and back panels into the bottom panel and add 1/4 inch screws to the tabs where they extend below the bottom panel hold the left panel in place.

Slide a 1/2 inch long nylon spacer spacer onto the input shaft to the left of the mid-panel, and then add the engine gear.

Slide another 1/2 inch nylon spacer onto the lay shaft to the left of the mid-panel, and then add the large lay gear.

Drop the mid-panel into the slots in the bottom panel and insert the three shafts through their corresponding holes in the left panel.

Secure the lay shaft to the left panel by adding a washer and 1/4 inch screw.

Slide a 3/4 inch nylon spacer onto the input shaft outside of the left panel. Then slide the handle onto the shaft and secure it with a washer and 1/4 inch screw.

Assembling the Output Section

Slide the medium lay gear onto the lay shaft, then add a 1 inch nylon spacer, and then add the small lay gear.

Add the collar to the output shaft.

Insert the remaining two gear holds into the right panel and secure them with 1/4 inch screws.

While holding the large differential gear in place under the gear holds of the right panel, thread the right panel onto the output and lay shafts and insert it into the bottom panel.

Secure the lay shaft with a washer and 1/4 inch screw on the right side of the right panel.

Assembling the Fork

The fork consists of one inner fork piece sandwiched between two outer fork pieces. Secure them with a 1/2 inch screw.

Slide the fork over the collar so that the fingers of the fork surround the collar on both sides.

Final Steps

Install the top panel and secure it with 1/4 inch screws through the tabs.

Attach the pinwheel to the output shaft using a washer and 1/4 inch screw.

Your Pocket Transmission is complete.

Dave Touretzky

Last modified: Sun Oct 16 01:00:07 EDT 2016