Mick,
Sorry to drag this old post up but could you not file/mill a flat in the flange of the bearing and print a D shaped hole for it?
Rob (still got upteen horsepower ringing my ears from 12 months ago..)
Rob, indeed, it was a bleedin good day out and I am missing it....I'm sure I may have mentioned that
The lock down won't last forever and I've banked 5 weeks of holiday; the company were very good at letting myself and my colleague, on the new crane site, carry a week over the 1st quarter threshold. Basically all staff....where practicable.....shall take one weeks holiday before the 3oth of April in an effort to maintain manning levels over the summer period.
Back to the gearboxes, that's a spiffingly good idea and much easier to accomplish, my previous idea was more akin to a raised key aligned parallel with the shaft. I'm not overly impressed with the Overland drive, there's an awful lot of drag and smooth it is not. Part of it I think is the outside bearings on the cast truck frames, there's a lot of looseness which appears to be translating into axle boxes not running parallel with the wheels stub shaft.
For my own models I'm going to draw up my own 3D gearbox using Roxey gears, wheels and some top hat ball race bearings.
These are the Roxey 3'-1" wheels whereby one wheel is screwed on, they scale out pretty close to 42" in 1;48 scale, except of course tread, flange etc etc, but the diameter is okay.
The plan is a standard inside frame jobbie with roller bearings, fixed outer axles and a little float on the intermediate axle, I'll sort the bearing outer case rotation somehow on that axle later. Having said that, the GEVO truck does not have a pivot point in the middle as you'd normally expect, it's actually ahead of the intermediate axle by a fair margin, 24.62" to be precise. Not exactly midway between the front and intermediate axles but maybe enough to have them rigid and the rear with a little float.
Or as is more likely, make the whole lot rigid, weight it heavily and let it level the track as it goes along
Plan is simply to shaft drive the intermediate and then forward to the leading axle with one continuous axle, that'll stop the gearboxes trying to rotate through torque and remove another UJ; I don't think I need the added traction of all axles. That means the UJ to the rear of the intermediate won't have a lot of swing and should keep the drive shaft pretty straight.
The rear axle will have a dummy AC motor 3D printed and fitted, the gearboxes will be a spin off from that in as much they'll be motor shaped as much as possible, certainly from below.
This is a standard AC motor in a standard truck, the transom is quite hefty so obstructs a lot of the view. On the other hand, the CSX radial trucks are much leaner and the transom much smaller, which gives better access for photos.
As can be seen, the AC traction motor is a hefty beast and there's not much ground clearance beneath them.
The motor rear mount is the long linkage to the rear, the lug at the top is a safety feature in case that linkage breaks and the motor tries to drop to the track. There are rubber bushes between the linkage and pin, allowing the motor to flex on the pivot.
If that all works out okay then I'll go back to the overland models, remove and store their wheel sets and make a drop in inner chassis to attach something similar to the above.
First thing though is to draw up an inner chassis etch, it has to be discreet enough to allow daylight where daylight needs to be and strong enough to support the weight as well as having tabs to attach the outer dummy side frames. As a test I'll work up a 3D print to get the shapes all right before committing to etch, though the 3D print will obviously have thicker walls. The inner chassis will also need the required clearances for the drive shafts and the traction/pivot point.