Servo Speed Mod

Anyone have any experience reducing the down-gearing in a servo geartrain by locking the first and third gears together and removing the second? I was trying to come up with a way to increase the speed (I don’t need the torque) of a hobby servo, and I hit on this idea, but I’m not sure if I should just glue the gears together (which might be too weak) or fix them with metal pins (which might cause the gears to crack). I only found one vaguely explanatory reference to the practice here, which doesn’t say how to do it, just not to (ominously).

I’m using some HS-311s as position control motors for a robot arm (post to the projects forum to follow) and it works great but is unfortunately slow. The arm is a modified MiniMover5 (1982 style!) which originally used stepper motors, so there is a lot of extra down-gearing outside of the servos.

Also, if anyone has other ideas for increasing the speed of a hobby servo (by ~10-20 fold) I’d be interested!

I successfully epoxied the gears together, and while I think I figured out an awesome way to do it, it was all for naught. With no load, the servo now flaps wildly, while under almost any load at all it struggles and can’t cope. Glad I bought a spare gearset to try this out on.

So, does anyone have any ideas for increasing the speed of a servo by a factor of 2, or maybe 3 (NOT 15)!


I don’t know if this is helpful,
but maybe there are some servos
that are faster than average.

It looks like the GWS NARO HP/BB micro servo
is the fastest one that Pololu is selling:

Or, maybe you could try a small gearhead-motor.
Something like the Solarbotics motors:

I’ve worked with the GWS Naro’s in a small snake robot before, and they are about as beefy as tiny servos get, but they’re way too lightweight for this bot.

You’re right though, servos weren’t really the best way to go. At some point I will probably swap out the servos for regular DC gearhead motors, and I do like the built in slip clutches in the solarbotics ones, but then I’ll need to set up a microcontroller system with 12 AtoD inputs to measure the 6 position monitoring POTs, not to mention tuning six control loops. OOof!

I’ve been meaning to get this arm working for a while though, and to motivate myself I made it my final project in an electromechanical systems course. The downside is that I have to present it in a couple of weeks, and while it’s slower than I’d like, it works great with the servos as is.


Just FYI,

here is a link where someone built a robot
arm using the Solarbotics motors: