Yes Terry, very true, they certainly were extremely good tradesmen back then. The machines were only as good as the operators but it now the operators are only as good as their machines. Both received great results.

I got the top off the trans today after a reasonable fight and the gears are in really great cond. I am even more confident this little tank will have it's original drive train running once again. I have a very good old school engine recon man taking possession of the Meadows next week to totally overhaul it. By the time I am ready for the engine he should be done with it.

I am well documenting this project because of its rarity and have already taken a couple of hundred pics.

What is the plan to disassemble the gearbox Colin? A thorough soak in something for a time first? Or does it just look worse than it is?

What type of alloy is the transmission case, Colin?

David

Yes jack, i'm in the process of getting it apart now and it only looks bad because it is bad :) but not the gears. I think that the bearings are also untouched. The electrolysis has not effected the steel from what I can see but I will evaluate them when I get to that stage. The box itself is basically flat sides all around so my thinking is do each piece individually with all machining done prior to assembly, tack it all together with bearings, shafts and gears and then Tig it all together. I would use the original top plates as they came off in good cond and to answer Davids question, I would think that it is a aluminium alloy and I can be assured that it has magnesium in it but its I don't know its exact composition is. I will keep the pics coming as I progress.
It sure is an interesting little project. :teach: :teach:

Colin, is it possible there is a case laying around somewhere?
Are they special to this mark of tank or could hey have used the same gearbox in other Vickers Carden Loyd machines?

Hi Lynn, as far as I know these boxes are only in the Vickers light tank and the odds of finding another exactly the same would be the old needle in a haystack scenario but I guess most things are possible. I think that if the gears were destroyed as well it would be a different story and by the end of today I should have it all apart. Then I can have a good look and make a better decision then. I might find that this one could be repaired which would be great so I'll keep my options open.
Colin

The pulldown is now complete and I don't think there is much chance of a rebuild. There's too much of it gone. It's mainly the bearing housings that would be of major concern to me. I will measure and draw each individual face for fabrication. One good thing is that I can use the original box to make the fabrication jig.
Colin.

After going through the bits and pieces, I found a few bits of the jigsaw puzzle. And before anyone says couldn't I weld them back on, the answer is no. The pieces are very thin and laminated but they certainly tell me what shape the bottom of the transmission should be.

Jigsaw with missing pieces
 

Oh.
My.
Lawd.
Mr Jones, I dips me lid.
:salute:

And me Howard. :salute: :salute:

Howard/Lynn, I wouldn't go dipping the old lid yet as it might turn out to be a very time consuming anchor :thup2:
Today I machined up the bearing aligning plates and rods.

I will make a self aligning spacer for the two rods so all the gears will be pretty spot on if all goes well.

Hi Colin,

This may have some relevance/be an option to your gear-casing problem.

http://www.abc.net.au/news/2017-03-2...ix-car/8310958

Mike :salute:

Interesting post, Mike.

I was wondering the same thing. A Technical College nearby had an open house a few years ago and showed off a brand new CNC Machine they had, along with a Lasar Scanner. The scanner could only handle objects about shoe box sized, but very detailed and the data was fed directly to a milling machine that cut a perfect clone of the original object scanned.

Using the scan data for a plastic sand mold of engine block size is brilliant!

David

Interesting Idea Mike, I have already had a company called Castech at my place to see what they thought. It was very interesting to say the least. The inside would need to be replicated to get a full scan. The inside bottom of my block is very badly pitted and laminated quite a ways up and that would need to be removed and replaced with a scannable material. Not to mention the price to get one done with no guarantee was very scary. I have already started my machining today and then my mill decided to play electrical silly buggers but I now have my plan off attack and more than confident i'll be able to make one. Thanks for your input though.
Colin.

Good luck Colin, incredible work! :salute:

What an incredible project, I think you have crossed the line between restoration and forensic reconstruction. Thanks for the detailed pictures, I will be following this with great interest.

Well put Russ !

I would like to add my name to the list of deeply impressed people too.

:note:

David

Impressed.....absolutely fantastic.......
 

I have seen better truck parts scrapped.

You have to be the most courageous and skillful restorer around. You are probably correct in assuming that you can replicate the boxy shape required to hold the gears in place the old fashion way.

Jay Leno, the California ex-night show host has a fantastic collection of vehicles and older TV programs on U tube...... one showing how they had a totally corroded complex valve cover recast using a scan from the old part. Now the guy is a millionaire and can afford to use the latest technology.

There was a press release recently on TV about the only two in the world 3D printer that are certified to make airplane components.. One is at GE the other is a joint venture between the University of Montreal and funding from the New York state............ they claim that eventually when it becomes more readily available and less pricey that it may revolutionize the manufacturing industry. They can produce, complex rare alloy titanium 3D parts from design to a finished machined product in 30% of the time needed in normal production with a saving of 30% on cost.

At the other end of the scale a local Hobby shop has a table top 3D printer made by Dremel that will make to whatever scale you need small parts for RC airplanes, boats, cars on demand...... he was making a replacement gear for a client when I was there......charges time plus material. Most of what he produces is already available on the web in digital form which he just downloads...... such as the upper torso of a pilot for a RC plane..... he scales it to the planes size with just a click....... he does not have a much needed scanner yet.

He had produced some mortar rounds for a local collector and one assembaled, the fins had to be done separately, and suitably painted they would scare a bomb disposal squad.

May we live long enough to see them reproduce a full size CMP......

Bob C

I have designed motorcycle parts that I had 3D printed to verify geometry on the bike before spending the money on machining. I believe it is also possible to 3D print a casting pattern, probably the approach that Colin's casting company was planning to use. It isn't cheap for something that size, probably well over $1000 and a full day on the printer. If they can't get a decent scan you could have the part modelled in 3D CAD and print a pattern from that. You would have to estimate the missing surfaces so it might not be 100% original, but in this case I dare say you'll never get called out on it. The only design constraint would be that it not hit the floor on the outside or the gears on the inside.

Thank you all for your words of encouragement. I will most certainly do the best I can and well document the entire procedure how ever it turns out.
Colin. :thup2:

I have started with the end that bolts to the bell housing first. Because the bearings are 20mm thick, I have used a piece of 25mm thick plate so by the time I machine it down, I will have a bearing stop and also a wider top to allow for the studs to be screwed in. I am using my rotary table in the mill to achieve the bearing holes.

There is one thing I can guarantee. It's going to be a lot heavier than the original. I have machined all the excess steel away, so the general thickness is now 13mm.

I am quite happy with my progress to date. The more I do the more confident I am getting that the end result will be OK

I thought I would show you how you can curve some plate quite easily by hand. I'm bending some 3mm plate 300mm long and it is just formed around a piece of offcut pipe.

With this method of curving, you can put as much or as little bend as you need. You just can't bend smaller than the host former. I also bend bren carrier front mudguards on this.
Now my sump is bent, I just need to do some cut outs, press the bottom for the sump plug and just make it fit any way I can.

So let me get this straight Colin...you are actually building your own transmission case from scratch?...now you are just making the rest of us look silly...shame on you sir!

John

Hi John, well lets say, I'm attempting to make it. :) :confused

Hi Colin,

Very, very impressive work there. Is there any particular reason to fabricate the new transmission case from steel rather than from an aluminium alloy as per the original? I know that aluminium alloy does cost a bit more than steel, but is there another reason? Structural strength and integrity or just using what's on hand?

All that said, I'm in awe of your work and the lenghts you are going to with your restoration. As has been mentioned previously, most wouldn't be so bold to tackle such a mammoth undertaking, with what most would consider to only be scrap.

Following your progress with great interest.