Tire diameters
 

According to the AEDB Design Record (I don't have my copy with me right now to quote percentages) there were significant differences in diamater between tires that were nominally the same ("same" size and all cross country) but of different manufacturer. Since I haven't seen specific reference to matching brands as a means to match sizes on a truck I doubt they used that as a method to ensure size match, but I have seen reference to measuring tires to ensure they were all of similar size on a vehicle. If they took the time to tell the maintainers to check, they must have found the size differences among "same" tires to have caused some kind of handling/driving problem.

Re: Measurements
 

Bob 1, No, I'm saying that a 2nd case ISN'T necessary. Rear drive is always 1:1 to the carrier bogie, and while the t/case is permanently in Low, the front axle is only engaged when required. This will work irrespective of 2wd/4wd.

Boob 2, I was talking about using the PTO output shaft which always turns 1:1 with the trans input, in fact it's connected to this very same shaft by a dog clutch. The normal rear output shaft cannot be made to run at 1:1 while the front is 1.87 : 1, but the PTO can only ever run at 1:1.
Finding a donor C60X t/case in order to replace the PTO housing will provide a stronger output for the drive to the carrier bogie.

Re: Measurements
 

At the Canungra Swap, I bought these NOS carrier backing plates off a bloke who said that he had a shed full of them back at home in Brissie. "Quantity was not an issue". Quite cheap, the price of the linings probably.

Exciting Break-Through
 

Hi All - Look what Ian Fawbert found. All we need to do now is identify the source of this diagram. Talking with the guru Lawrie, he says ADD(X)868 probably stands for Australian Defence Diagram(Experimental)868. Ian states that CVT. in the title of the plate stands for Chevrolet. I had always thought this truck was made late 1942 to early 1943, but the signature on the bottom right gives a date of either 14 or 16/4/44. However Lawrie thinks this diagram could have been made up after the manufacture of the truck, as many were. This could be correct as the description says "Prepared From ADD(X)868, suggesting it was copied from an earlier drawing.

I invite comment/further interpretation.

Once again, a big thanks to Ian.

Update on progress - carrier wheels are being re-rubbered and the Hino truck truck is getting a paint make-over.

Bob

Wow!
 

Well done all concerned! :salute:

Note the GM part #s, so it's definitely a 134" Chevrolet. Do the diff. part #s mean anything please, eg they are from a 4x2 say?

That is the score of they year I would say, nice work!

I...
 

:salute:...agree about that!

Add(x)868
 

Hi all - the word from Mike at the AWM is as follows;

Drawing code: Army Design Directorate (Experimental)
Project code 868.
CVT: Chevrolet.

Now we have to track down Project 868.

Bob

Rear Drive Sprocket
 

Hi all - discussions last night with my guru, Dingo Man, led us to Mike Cecil's book on Carriers. Whilst discussing the Tracked Truck we discovered that its drive sprocket was a 42 tooth sprocket. Colin and I had calculated that the Phoenix sprocket was 43 tooth, but maybe it could be 42 tooth. Next question, was any tracked vehicle fitted with a 42 tooth sprocket so that GM could utilise that as opposed to manufacturing a new one. Am I correct when I say that the Vickers Light Tank utilised Carrier tracks, and if so, how many teeth were on its drive sprocket? Also was the Vickers fitted with Pommy or Oz track?

Bob

Bob,


The Vickers Light Tank pre-dates Australian LP carriers so would be fitted with British tracks (Pommy as you say). I think this was discussed recently with Colin, but I seem to recollect the Light Tank had a slightly wider track fitted, according to an amendment in the manual dated about 1937, and also think that it is wider than a British carrier track. Can find no mention of number of teeth on the sprocket though.

I've had a thought ...
 

... doesn't happen often so I thought I'd share it - maybe someone has even mentioned it before.

If you were starting to build this thing, and you had the standard chassis, transmission, diffs, wheels and tracks on the shelf, the obvious difficulty is matching the wheel drive ratio to the tracks, as per all the above discussion.

There's also been a lot of chat about the track sprocket tooth number, but wouldn't it have been a simpler option, at time of original production, to make one or more special pairs of drive sprockets with slightly different diameters and numbers of teeth? Obviously you would start by knowing what the front drive roadspeed should be, but specially-made drive sprockets would let you match or iron out any variations, within the limits of being too small for the tracks to run round or so big they hit the 'body'

Build it first, with standard carrier drive sprockets, and try it with the front axle out of gear, then measure it, then fit track sprockets with extra or less teeth till it's a perfect match with the front axle in drive?

Oh, and I hope it's going to get a real body and not that collection of concrete blocks like the original did in the photo.


Good luck.

Re. Thought
 

Hi Gordon - thanks for your thoughts. I think we will go with the 43 tooth sprocket. As far as the body goes I will stick with the concrete ballast body as that is how the vehicle was conceived and tested. I want to replicate as close to the original as I can.
Bob

No problem Bob
 

If you were building it today stick with standard sprockets and leave the front axle out of gear for now.

I still think you might consider a special body too, maybe in addition to the concrete ? I expect there would be plans out there somewhere for what they intended as the final result.
Time enough for that when you get the rest of it up and running.

Gordon

track
 

the Vickers Light tank(Mk 6 I think) was fitted with the wide track. Or if you like, the Aussies opted to use the Vickers light tank track on its locally produced carriers. I am speaking of dimensions here, not about metalurgy,or pin location etc.

Wheel Bearing Help Needed
 

Hi all - just rebuilding the front axles and noticed that the nearside inner wheel bearing is missing. This is weird as you need to dissemble the whole hub system to get it out. Looks like someone forgot to replace it. I need to order another one but I do not have the part number for it. Help needed ASAP
:confused Bob

Phoenix Truck
 

BTW - if you don't remember this is a C60S.
Bob

Phoenix Rising - The Power Of Colin
 

Hi all - finally got the truck to Colins a couple of weeks ago with the intention of doing some working bees with him. Received a phone image today and lo and behold look what this guy has done. I was gobsmacked to say the least. He then sent me some images of the stages. More to follow.

Bob

Pt. 2
 

So this Saturday the plan is to re-construct the wheels and next week get the 43 tooth sprockets made. This is truly amazing as is MY MATE COLIN!!

:D Bob :D

So we WILL see you and Phoenix at Corowa then.
Rick

Corowa
 

Hi Rick - all is a go, but remember Murphy.

Bob

Murphy
 

I asked Sam Kekovic to speak to Murphy and he told him to 'get stuffed' and keep away from your project so you should be OK.

Supplemental question Sir......
 

Nice job Bob....

What is the thickness of the plate used for the track assembly....? what would be the original thickness of the side plates supporting the suspension on a UC...?

Will the frame be boxed..... or stiffened with a backing plate inside the frame.....or with additional frame cross members to hold sideway stress....?

Curious and facinated with the design.

Bob C.

Credit
 

Hi Bob C, all credit has to go to Colin and his expertise. I'll let him answer your questions.

Bob

Today's Progress
 

Hi all - working bee today. Removed rest of brackets, etc. off chassis rails whilst Colin fabricated the sub-frame to hold the front track adjusting wheels. Then much drilling of holes.

Bob

Well done Boys, I am really looking forward to seeing the beast in action!

Hmmm Hmmm Hmmm
 

Looky looky

:D Bob

Awesome!
 

You de man, or should I say you AND Colin de men! :thup2: :thup2:

Now add the wusty twack a lick of paint, a slab of concrete and Robert's your mother's brother!

looking really good Bob. :thup2:

Finishing Off
 

Hi guys - Colin is definitely THE MAN. I have never seen so much energy and creativity. And you ain't seen nothing yet, wait for our trading tables at Corowa.

:D Bob

Finishing Off 2
 

What I also meant to say was that I have heard of numerous instances where the pain is still drying en. route to Corowa. This will probably be the case also.

Bob