Hardened Shaft Gearbox

2025 Update - Due to substantial import tariffs, an additional $2.00 per gearbox is currently being applied to cover these costs. Thank you for understanding. 

These are the 30:1 gearboxes that have been well proven in our High-Temp Hardened Shaft (HTHS) 1400rpm N20 motors.

Installed in our motors they will have the below rpms on 2S:

N10 - 1200rpm

N30 - 1000rpm

These "replacement" gearboxes include the 2 mounting screws and the pinion gear.

*** Installing these gearboxes on any motor OTHER than the Turnabot HTHS 1400rpm N20 motors will require removing the original pinion gear and installing the included pinion gear.

The "right" way to remove the pinion gears is with a proper micro gear puller. (available on Amazon)

The "right" way to install the gears is with an appropriate press or vice with fixturing.

 

That said, AT YOUR OWN RISK, it "can" be done with TWO micro screwdrivers (if you use one you're almost guaranteed to bend the shaft), any type of compression device that keeps the jaws parallel, such as Knipex or a vice with flat jaws, and something to support the small silver disk in the black plastic caps, such as an M2 machine screw. You'll also need something to allow the shaft to press slightly beyond the end of the gear, the screw holes in the old gearbox can be used in a pinch.

Below are instructions with pictures of a worst-case scenario (unexpectedly at a competition for example) "hack" option for replacing gearboxes. 

With a micro-screwdriver remove the 2 screws holding the gearbox on.

Use TWO tools to EVENLY pry the gear off of the pinion (again, using one is nearly guaranteed to bend the 1mm shaft):

You can usually set the gear into position with your fingers. One side of the gear may slide on a bit more than the other.

You may find it much easier to attach the machine screw to the compression device as close to edge as possible. It can be done with tape like this:

You can GENTLY press the gear flush to end of the shaft with the Knipex:

That will only get the gear to end of the shaft like this:

In order to get it all the way on you'll need to use something like the screw hole in the old gearbox:

That will let you get the gear SLIGHTLY past the end of the shaft like this:

You can see in the below 2 pictures how the pinion gear is now centered on its mating gear:

 

N10 Motor CAD STL Model

N10 Motor Motor Mount CAD STL Model

N20 Motor CAD STL Model

N20 Motor Mount CAD STL Model

N30 Motor CAD STL Model

N30 Motor Mount CAD STL Model

Price is for 1 (one) gearbox

Speed Calculator

Some brushed motor basics:

Torque and stall current have a near linear relationship. Cheap N20s are very weak and have appropriately low stall currents. For comparison on 2S:

Cheap N20 motors (often as low as $4 each) often stall near 0.25 amps and are working hard to move 150g and generally cannot push another 150g around.

Decent N20 motors (usually in the $7-$9 range) often stall near 0.45 amps and while they'll move themselves around fairly well, they are not likely to win many pushing matches.

"Good" N20 motors (usually in the $10-$14 range) generally stall closer to 0.90 amps and have real "authority" with 150g bots and are occasionally used in 1lb bots.

Before we had the Turnabot N20 motors made the "best" N20s we were aware of were rated at 1.60 amps and "appropriately" $18+ in cost.

Turnabot N20 motors stall at an incredible 2.0+ amps on 2S. It is VERY hard to stall these with common insect weight drive systems so using one of them per side on 2.0 amp ESCs has not been a problem.*

*Please note!* Most 2.0 amp ESCs, will NOT run 2 Turnabot N20 motors per side. This includes the "standard" Malenki-Nanos for example. That said, while the Malenki-Nano-Integrated-High-Voltage (MNI-HV) is technically rated at 3.5a per channel, testing shows that most run just over 4.0a and are an excellent match for 2 Turnabot N20 motors per side.

Turnabot N10 motors stall at 1.0+ amps on 2S. This 1.0 amp "nominal" is also the appropriate limit for running two of them on ESCs with 2.0 amp max ratings.

 

Please note that even the 3600rpm N10 motors have enough torque that with four of the stickiest tires we're aware of, a 2S lipo at it's minimum suggested voltage (7.4v), and while carrying another 150g bot (300g on the wheels) these will still spin all four tires. The lower rpm motors can spin four sticky tires even in 1lb bots.

This much power in this small of a package means these motors should NOT be stalled for any length of time.

 

Not all "N20" motors are the same!!! N10 motors are smaller and lighter than N20 motors. Turnabot N10 motors are more powerful than "most" N20 motors.

We have additional motors that are not listed here in our "standard offerings." If you need any specific Nx0 motor / rpm / power / stall current / voltage, please reach out to us with specifically what you're looking for and we'll see if we have something that will work for you.

More details here:

https://turnabot.com/blogs/turnabot-tales/brushed-motor-stall-currents