Motor And Gearbox

The motor/gearbox turned up today in the mail from the UK. It’s a beautiful bit engineering from ABC Gears with a coreless Maxon motor. I’d originally planned to use a Slaters motor/gearbox but I felt that this was too large for the job. In addition to this the person who had machined my driving wheels a few years ago to reduce the depth of the flanges slightly had installed one of the retaining pins on each axle with some liquid retainer, making it impossible to remove the wheel from the axle without drilling out the pin. The Slaters gearbox was supplied with a Slaters axle already installed, meaning that if I wanted to use the original gearbox and motor I would have to remove the wheel from the axle on at least one of the wheel-sets. The chance of damaging the wheel in this operation I felt wasn’t worth the risk so I opted to get myself a new gearbox and motor. I can always use the Slaters gearbox and motor in another project or sell it.

This photo shows the ABC gearbox installed in the chassis. You can see a lot of the gearbox at this angle and this will be apparent even when the loco is complete so I will have to experiment with pushing the motor forward into the boiler. This will depend on space and clearance.

This photo shows the ABC gearbox installed in the chassis. You can see a lot of the gearbox at this angle below the chassis and this will be apparent when the loco is complete, so I will have to experiment with pushing the motor forward into the boiler to see if I can raise the bottom corner of the gearbox up a bit to help reduce its cross-section. This will depend on space and clearance.

I’d done some preliminary work on getting the side rods installed and they had been fitted to the wheels so all I really needed to do to test the mechanism was slide the rear axle and wheels out, position the gearbox between the frames and slide the axle back through the gears, gearbox frames and the sprung horn-guide. The main gear on the axle is retained with a small grub screw. Hobby Holidays, who produce the ball bearing hornblocks I’ve used in this project, and ABC gears suggest that their products don’t require much if any lubrication because they are supplied pre-lubricated, at least enough to test the components. So I applied some power to the motor leads and gave the mechanism a trial. There was a small click in one of the rods and I was already aware of this from testing by hand turning the wheels but it was still apparent when the motor was switched on. I’ll have to work on this. In spite of this the motor was beautifully smooth and almost silent with a significant inertia effect apparent even though there is no fly-wheel.

Hey Bruce, I have little wheels turning. Looks like I might get to make a selection after all. Now what should I have? 🙂

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4 thoughts on “Motor And Gearbox

  1. G’dayTrevor. Although I do not model 7mm I am following your exploits with the Z20 it certainly pays to use the best available.I look forward to more updates on this project.Peter

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