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Motor shaft extension??? Is there such a thing???

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I have a couple of the Thorp extra long pinions, designed for use with an adjustable motor mount. Since the mount pushes the motor away from the spur gear, a Thorp extra long pinion made up the difference.  But they aren’t cheap. And they only come in one pitch, 10t through 16t.

And with my newest experiment, I’ve added a new motor mount to the Bushy D (Bush Devil ORV) so I can run a Thorp extra long 13t pinion.  But even with the extra length, the pinion grub locks down almost at the end of the motor shaft. 

so my question:

Is there a 540 motor shaft extension???  Something that sleeves over the motor shaft and adds Xmm of length???

or: how do you make a motor shaft longer???

Terry

 

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when i was building the Bluefish i had to use a brass tube for the dog bone couplers diameter holes (being it's a twin motor drive) so i had to do both motors.

The brass tube cut to length and used LOCTITE 638 Retaining Compound. now that said this 638 basically chemical welds tight tolerance metals like nobody's business, i use it for my FE boats cable and shaft drives and it has never failed.................yet.

so like if you went from 3.17mm and stepped up to 5mm pinion (then you could have more teeth to chose from), you could use Stainless steel tube also and stuff the remaining void inside with a steel rod (drill bits work well for lots of Pin work).

well like every thing we get to experiment with it would be fun trying.

or find a longer shaft or different motor.

i've cut motor shafts down before that's easy, extending is another.

they also have reducer sleeves https://www.amainhobbies.com/robinson-racing-3.17mm-to-5mm-reducer-sleeve-1-8-to-5mm-rrp1200/p25015

i do not know how far it can hang over though.

 

 

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schumacher also sell long pinions, not sure if they are suitable for you needs though?

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The devil on my shoulder says I should mention that 1/8 brushless motors have the same 25mm hole pattern as 540s, and have longer 5mm motor shafts. ;)

The basic problem with trying to extend a motor shaft is that unless it fits absolutely perfectly and is perfectly straight, you will introduce eccentricity and wobble in the pinion, which will make it noisier and probably introduce tight spots and undue gear wear.  (This is true even of a long pinion. 

@ACCEL has very good points about using brass tube and loctite 638 (I use this for 'welding' gears onto shafts, and he's right, you will never get a failure, I put the torque from a 2400 Watt turnigy brushless boat motor the size of a coffee cup running 6S through my War Rig gearbox, and it's fine), however, I suspect the brass tube would fail before the loctite when using it in a buggy (Transmission doesn't suffer the same shock loading in a boat that a buggy does).

If you're just running a silver can I would look around at chinese 550 motors. They're a bit longer due to having an internal fan so they can take 12V, but some may have longer motor shafts as well. If you want to test the rest of the transmission have a look at turnigy / hobbwing 1/8 2000KV motors. Loads of grunt and never get hot on 2S

 

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How much extra do you need? Some motors have longer shafts from the factory. The traxxas Titan 550 for example.

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