VICKERS MK6B's resto

[colin jones]

Hi Lynn, yes as a matter of fact, my band had a Pub gig last night.
Hi Russ, I had little to no distortion. I tacked everything in place first and kept my bearing plugs and rods in place the entire time. I also tack welded it down to a heavy plate to keep the top flat at the bottom ( the top of the trans was at the bottom and that is what I tacked) I used a series of clamps and did small sequence runs like tightening a head and let them cool naturally. I kept checking measurement as I went and also welded flat bar spacers where I thought it might warp and to my surprise it came out very good. The sump won't be a problem as it has now got some independent strength. The only part I need to be careful of now is welding the bearing housing in the centre as there will be a fair amount of heat go into it but I will have to again do short bursts. It's annoying doing that as I'm a bit impatient when I want to get something finished. After the sump is done I only have the side wing parts bolt holes and stud holes. All going to plan.

[Alex van de Wetering]

Colin......awesome work! I am enjoying this thread just as much as the threads on HMVF where the guys are restoring WW1 trucks.....making stuff from scratch, turning, milling, bending, brazing, welding....

Alex

[colin jones]

Thankyou Alex, I too am finding it very interesting and a great challenge.
The sump has almost been completed.

[colin jones]

I thought this part was going to be a lot harder than it was.

[colin jones]

I won't weld this part in place until I do the sump plug and weld and grind the inside as well.

[David Dunlop]

It's fascinating, Colin, watching this housing come back to life. The steady progression from 'What the hell IS all this stuff?' to 'OK…NOW I see what it's all about!' is incredible.

What puzzles me, is the original design decision to go with an alloy housing in the first place, rather than something cast/machined out of a mild steel. Weight saving jumps to mind straight away, but I wonder just how dramatic a saving there would have been?

It would be interesting to compare your finished case in weight to a best guestimate of what the original case would have weighted just to see what the difference is. It is not uncommon for armour power plants to be referenced with a BHP to Total Vehicle Weight ratio as an indicator of how well they can handle the job. I cannot imagine a weight saving from an alloy case making that much of a difference to engine performance in this instance. Maybe a change in center of gravity of the vehicle was being considered to better the distribution of weight on the suspension system.

In any event, it is great fun watching your progress!

Cheers,


David

[motto]

Looked at in isolation the use of an aluminium alloy for a transmission housing seems odd but it seems at this time it was simply an industry standard for some British manufacturers and may particularly apply to low volume items. Some vehicles even featured alloy differential housings which appear very strange to modern eyes.
What a fascinating thread!

David

[Lynn Eades]

On a visit to Colins, he pointed out to me that there was extensive use of aluminium in the Vickers light tanks. Likely the influence of their aviation interests.

[Tony Mathers]

Most Tank manufacturers of the time made extensive use of aluminium in Light tanks. The Panzer I was the same with mudguards, floor, wheels and tracks, as well as the engine and transmission made of aluminium alloys.

[Grant Bowker]

Use of aluminum might be for weight, but it might also have been for lower melting point or ease of machining. Maybe a combination of "all of the above", I don't know the true answer.

[Richard Farrant]

The gearbox casing is quite likely to have been cast from Elektron, which was a magnesium alloy developed by a German company in the Inter War period. A company was formed in England in the early 1930's to produce Elektron castings. I know that the gun mantlet in the Vickers Mk6A was cast in this metal. It is light and stronger than cast iron. The gearbox casings on the Ferguson TE-20 tractor were cast in this metal and are part of the main spine of the machine, so on doubting the strength.

[colin jones]

I don't think it would have been a weight issue, although my trans is probably 6-8 times heavier. Looking at mine now, I think I could have cut down the general thickness and still retained it's strength. I think it would have been for ease of manufacturing. If I was capable of casting, then I probably would have gone with ally as well. But I'm still happy with my progress. I had and estimate of $10k just for the wooden plug then it would have to be cast and machined. So It would have been upwards of possibly $20k and still no guarantees.

[Tony Smith]

Originally Posted by colin jones

But I'm still happy with my progress.

Understatement?

[colin jones]

I have now had the gears in and checked for clearance and all is good.

[colin jones]

I also put the side bearing housing and cross shaft for a test fit and that too is good and the bevel gears appear to mesh correctly.

[colin jones]

Well that's it!! i've welded the bottom on so I hope I don't need to do anything else in there or I'll be cutting a hole . Centre lines all lines up, the gears all mesh well and I can turn the main shaft and get the gears to respond so that's a plus. One of the bearing housings in the centre must have got a little bit too hot so I will have to do a bit of mods with my die grinder but no biggy. The outside wing parts are next then the holes and tapping.

[super dave]

Again WOW, I think that only you could have done such a feat as to manufacture a complicated transmission housing

[Russ Gregg]

A hundred years from now this will change hands of the rarest of all Vickers Mk6B's, the only one with the steel gearbox upgrade. There will be all sorts of speculation over whether it was a factory prototype or done as a training exercise for the motor pool etc. Nobody will guess clever Aussie in a well equipped shed.

[Mike Cecil]

....Unless Colin does what Museums routinely do and stamps into it the date made and by who, thus clearly indicating it as a part manufactured during restoration.

It is a common 'problem' with restorations particularly where records can be lost or mislaid: just what is an original part and what is substituted from another source. Without clear indicators such as the stamping mentioned, it can lead to all sorts of speculation and assumptions.

Mike

[colin jones]

Thankyou Dave, but I think you are underestimating so many guys here with some of the resto's that have been done.
Mike, that's a good Idea. There is a plate on the trans cover that is all but gone so I will replace it with one of my own. Perhaps I might put "Panzervicker" and give them all something to think about in a century or so.
I started the side parts today and even thought the two parts I made don't look very big or complicated they took me all day and it took quite a while to get them set up for the correct radius but I got is at the end.

[colin jones]

These two pieces are 1" thick steel and they are now drilled and tapped with 3/8 BSF threads.

[jack neville]

It will be an interesting observation in the end Colin that the most heavily armoured part of this tank will be the gearbox.

[colin jones]

I set my original box on my work table and welded stays down to it with braces to stop movement while it gets welded. I have also cut my pieces on my new CNC plasma machine. They take some getting used to but cuts great and very accurate.

[colin jones]

It is now welded and just need some flap grinding for some neatness.

[colin jones]

I missed a couple of welds but now they are done also. Time for some holes and tapping.

[colin jones]

Almost finished all the holes and tapping today with about a dozen tomorrow. Big job and quite slow.

[David Dunlop]

When you add your data plate, Colin, it deserves to be gold plate!

David

[colin jones]

Yes Dave, unfortunately I'm fresh out of gold plate but I did bolt the side plates on and the front housing. I also put the front shaft in to check its centre with the side curved parts and found a variation of a few mm. The shaft is very good and the speedo helical gears match really well and spins when the shaft turns with no play. That means that the wing parts I put on will need modification. I should have been more careful and triple checked critical parts before I weld them all together. I guess it couldn't all go to plan with out some form of mod . It is not a big job to fix but I will bolt on what ever it takes to get it exact before I weld it back again.

[colin jones]

Well that's about it for fabrication. My transmission casing is all but finished. I have put some gears and other external parts on and it's all good.

[colin jones]

I am really happy with my result and also glad I decided to go this way. I now need to give it a really good clean, de-burr and undercoat. There are a couple of external parts that I need to make so I'll do them now too.