Quad gearbox

[Daniel Scholefield]

Having just assembled the gearbox for my Quad I am left with a quandry. All the shafts, gears and bearings went together with no issue and turned freely, the housing went on with no sign of binding.
However once all the bolts were tightened up I could not turn the bottom drive shaft at all. I have taken the box apart a few times and can find no evidence of anything grinding so my question is, is the lack of movement normal? Is it just the resistance of the motor or do I have a problem?

[sean kerambrun]

Hi Daniel,

It was a while ago when I built mine but I don't remember that problem.. the DC motors turn pretty easy. But I cant even remember if the motor has a reduction gearbox on it. If there is a reduction gearbox that will behave that way

Cheers

Sean

[Adrian Harris]

> Is it just the resistance of the motor

Easy way to test would be to leave the gearbox intact and just remove the motor.

If you can turn the final shaft with the motor removed, then the gearbox is OK and you're just seeing the effect of the gearing trying to turn the motor.

Adrian.

[Daniel Scholefield]

Well I took the motor off and found that it was still binding up as soon as the case went on so that ruled that out as the cause. Taking it apart it seems the issue is with the top shaft as it was still stuck to the bearing. Freeing the bearing I tested it turns freely, as does the shaft resting in its bushing so I put it all back together and once again it jams as soon as the case goes on. The rubbed off paint suggests the gear is pressing against it but that might have been from my testing with the case off so still not sure what to do.

[Adrian Harris]

I had a discussion with Mark about this, and his response about EM0503 was:

"This bush should be 1mm proud of the face of the gearbox when fitted, preventing the gear
from rubbing on the face. You can fit a thin washer if this is not case on your build."

I think I found an M6 brass washer was the ideal size. You will probably need a "Form B" type, which should be 0.8mm thick for an M6 one.

Adrian.

[Daniel Scholefield]

Thanks Adrian, I will get the appropriate washer and give it a try. It does explain what might be happening as I push the case down.

[Adrian Harris]

<fingers crossed>

Are all the bearings flush with the gearbox face ? If they are proud then you may not have enough clearance from that end.

Adrian.