Coleby Junior Restoration

[ssorthiek]

Now onto the gearbox rebuild again.

The gearbox has now been fully stripped down and will be going off for welding shortly and something done with the PTO shaft all being well. The bearings have been removed and I might take the opportunity to get the casing shot blasted and powder coated, but this risks the bearing surfaces being shot blasted as well. We shall see.

Meanwhile I have been busy cleaning the internal bits an pieces. One of the gear cogs seems to have quite a bit of wear but this machine will probably only ever see light work going forward and it looks as if it would mean getting a whole shaft and gear made up, a cost which I’m not too keen on at this stage.

I though I would include a couple of photos of the drive mechanism. The two wheels are normally locked together (ie no differential) and occasionally one wheel is disengaged which enables turning. I think this was quite common, but believe Fredrick Coleby patented this in the 1930’s. I hope to find the patent applications for this soon.

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[ssorthiek]

Still on the gearbox, I didn’t realise that the left and right hubs were different. I need to go back and look at photos and decide which goes where, just as well I kept all the components together for the left and right hubs together. I’ll soon have my other Coleby Junior to do a comparison in any case.

What I have found is that there is a home made thrust bearing on one side but not the other. I suspect that this was a factory made bearing and was “good enough” for the low speeds it was intended for.I also think that this might have been an addition on a later model.

I’ve been wanting to paint something for a while now. I have had some bits powder coated which I think I’ve mentioned before, and hoped that the colour was a good match. I think it is but need a bit of daylight to have a really good look. I also need the paint to dry. I suspect, if the colour of my hand are anything to go by, I’m onto a winner.

So, now photos of the other hub assembly and some newly painted hub housings.

Incidentally, the thrust bearing surface is quite pitted and I would welcome any thought about the longevity of this bearing considering this machine will only ever see light use and the speed is likely to be of the order of 30 rpm at top speed.

Finally, I have found numbers stamped into some components on non-critical surfaces. I assume these are part numbers which in itself is interesting. The last photo show one such marking. Can anyone confirm this or provide any additional information at all?

Keith

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[charlie]

The pitted thrust washer in second photo looks as if it is the outer race of the bearing. The Monrotiller gearbox has a similar bearing.

[ssorthiek]

Thanks Charlie, I should have taken a photo of the casing the other way up really, but the phosphor bronze bearing in the casing is sandwiched between two steel hollow shafts about 1/2″ long. I think they both have male threads on them but I’m not totally sure about this at the moment. Anyway, the inner retaining shaft has the other half of the thrust bearing outer race, and fits together quite nicely. So yes, you are right the second photo above is one half of the outer bearing race while the other half is really part of the hub casing.

[rollomk6]

Hello I have a Coleby Junior in my collection it is fitted with a plough it is powered by a 25a villiers two stroke I also have some paperwork for these machines

[ssorthiek]

Thanks rollomk6, this is certainly interesting and I would certainly be interested in talking to you. Is this one on the Coleby Register by any chance? I know that one of the members has a register and I have asked him to put my details on with both the Coleby Juniors I have on it.

[ssorthiek]

GEARBOX

Well, the gearbox has been sent away for welding and the main driveshaft is away being machined. The shaft will have a collar heat shrunk onto it as recommended by charlie but if all else fails, then a new part can always be machined.

There is little to do until I get this back but the weather has turned hear in the North of England so it is time to take a break and spend time with the wife.

Keith

[ssorthiek]

Well, the gearbox is now back from the welders and the main worm shaft has been turned down, a collar heat shrunk on and turned to size. All looks good but I do need to helicoil one thread. 5/16″ BSW helicoil is hard to find a guess but I will keep my eyes and ears open.

I have just been cleaning the casting tonight and I think it should be all systems go either this weekend or probably next weekend if the weather holds out. It’s getting a tad chilly out in the garage.

I need to revisit the paint job on the hubs I think. The paint has run for certain and I think there are fine, almost dust particles on the finish. I shall look at this next time I’m in the garage, but for now I’m happy warming myself next to the fire!

[andyfrost]

5/16 whitworth helicoils are readily available.

Andy

[ssorthiek]

I have now spent a couple of weekends trying to sort the garage out, making it into a workshop ready for the warmer weather. I’ve now made myself a bench, got myself a little lathe, sorted out the pillar drill and so forth so it is all systems go for a gearbox rebuild.

I have found some Whitworth helicoils which is all to the good. There are no promises, but I hope to get to a show sometime this year and display both my Colebys off to the general public. I suspect one will be work in progress but the other one runs quite happily at the moments, but seems to need a bit of attention to the clutch, I suspect that it needs a bit of a service. Unfortunately the inspection covers are seized (on both Colebys) so the machine will need to be taken apart to gain access.

Hampering progress at the moment is my finger. I managed to cut it with a bread knife resulting in 5 stitches 3 months back and having had a chat with some clever medical people a few days ago, they seem to think that I need surgery to get it back to normal. If that really is the case, the Coleby will have to take back seat again, not a position I want to be in going into Spring.

[ssorthiek]

Having sorted out the issue with the 5/16″ helicoils, I started to rebuild the gearbox. All was going well until I decided to try and press the bearings on with the bearing housing into the gearbox. As you can imagine I got the bearings halfway on but the stress was to much for the aluminium gearbox and three cracks appeared.

Off to the welders again who did an excellent job repairing the casing. All the holes were filled which gave an excellent opportunity to drill and re-tap with the correct size threads. That was this weekends task.

All I need to do now is to carefully rebuild the gearbox. One issue I have is when I took the gearbox apart, there was a thrust bearing. But there was nothing stopping the thrust bearing moving along the shaft. I just need a spacer. However, one side of the thrust bearing must of course be running at the same speed as the shaft and the other must be running at a different speed (stationary) for the ball bearings within the bearing race to be effective. I’ve come up with an idea for a suitable washer / housing to sort this out, but wondered how other machines are set up with regards thrust bearings.

[charlie]

Could you show a diagram or photo of the setup as it is so we can see how shaft, bearing thrust washer and gears are arranged at present.

[ssorthiek]

The Coleby is really starting to take shape now. There have been quite of few issues on the way including gearbox cracks, cab problems, broken engine governor, sometimes a less than understanding wife (although she is understanding most of the time).

One of the biggest problems I have had with the engine is getting it started without petrol. I can tug at the pull cord all I like without petrol and she just won’t fire! Three times I’ve tried this. They say you live and learn.

I managed to get down to Newark and bought a new WICO series A for spares. I should be able to get the other up and running soon.

Pictures will follow again soon when there is a bit of sun. I’ll hopefully be showing this again next year at a couple of shows but it does get expensive hiring a van for a weekend.

That’ll do for now I guess.

[ssorthiek]

Oh, I managed to work out what was going on with the gearbox I think. Someone had tried to overhaul the thing and just left the thrust bearing off altogether. I just fitted one in and it fitted perfectly (I think). Time will tell. Thanks Charlie for the post.

[ssorthiek]

After quite a struggle I have managed to get the Coleby Junior running. The engine has been running for a while now put there were (and still are) issues with it. The piston rings are probably worn since it uses about a gallon of oil to every half gallon of petrol and there are issues with the governor. Still the gearbox was all assembled, clutch fitted engine running ready for a quick run around the local bowling green. But seriously, I’m dead chuffed, all I need to do is repaint it with some enamel paint with the hope it will resist petrol. A few other odd jobs including getting those piston rings changed and it should be ready for next years shows.

Once painted, I’ll throw a few pictures up for all to admire (or otherwise).

[Author]

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