Naught for Not - 4 Motorized Square Gears

I thought a four square gear, motor driven assembly, would be an interesting conversation piece.

3D Printer

PLA filament - any color

Mini Micro N20 Motor, 3-6 V, geared to ~30 RPM, $7 for qty three, Amazon

2032 3V Battery, $5.35 for qty 10, Amazon

2032 Battery Case with Built in Switch, Collao, qty 6, $5.59, Amazon

Soldering gun

Solder

Flux

Hot Glue

Hot Glue Gun

Here is a non-productive gadget that is good for viewing, but not much else.

After making the square gear tie clip (provided to Instructables elsewhere), I thought it would be interesting to try to make a set of four gears, driven by a slow speed DC mini motor. After a couple of fails, this design seems to work.

The three gear shafts have a design clearance (tolerance) to the gears of 0.23 mm.

The motor shaft to driven gear has a clearance of 0.135 mm for a nice press fit. The motor shaft has a flat, so it has a nice positive torque transfer to the driving gear.

The other three gear shafts to gear have a clearance of .23 mm.

Rather than having the base and motor mount printed in one piece, they are printed separately. This reduced the support requirement a lot, but needs super glue to assemble.

The single 2032 battery holder comes with a built-in switch, which is very convenient compared with a separate switch. I found that the battery + side should be facing you when installed.

Details on how I developed the gears is provided by my Instructable on the Tie Clip.

Print the STLs

Motor Wiring / Assembly: The Battery Holder wires a too long for this assembly. Cut the two wires to make them 28-36 mm long. Remove about 3 mm of insulation from each wire.

Solder the wires to the motor. Install the 2032 battery and test to confirm the motor turns with switch on. If it does not turn, turn the battery upside down. (I had to do this, but don't understand why this was needed.)

Install the motor into the 2q-5 Motor Mount. Make the Motor Face flush with the edge of the Motor Mount so that the Small Collar around the shaft protrudes.

Install 3 Gears: Place the three 2q-2 Gears (the driven gears / with larger round holes) onto the three shafts on the 2q-3 Base. Clip on the 2q-4 C Clips to the shafts. Ensure the gear turn smoothly. If rough, turn several times to reduce the print anomalies.

Pre-Assembly: Pre-Check. Place the Motor / Motor Mount Assembly (Assembly) onto the 2q-3 Base with the Small Collar pushed into the mating hole. Ensure the Assembly is similar to the drawing / pictures.

Assembly: Remove the Assembly and place hot glue on the foot of the Assembly and reinstall. Ensure the Collar goes into the mating hole. Hold Assembly tight to the Motor Mount for 3+minutes. Hot glue two edges of the Assembly to the Base.

Press fit the 2q-1 Square Gear Motored (the gear with the small hole with a flat) onto motor shaft. Line up the flat on the gear hole with the flat on the motor shaft.

Hot glue (or super glue) the Battery Holder to the Base per the photos, or as you wish.

Test: Hold the Motor Mount and turn on the switch. Ensure the gears turn. Show it off to a member of the opposite sex. Determine if he/she is impressed. If not, make a decision on the relationship. (My spouse was mildly impressed.)