How To: Ford CMP "Blitz" miscellany

[Jacques Reed]

Good Day All,

Firstly my apologies if this has been covered before but I am seeking some info on the bridge classification disks used on Australian CMP's.

I just need confirmation of the diameter and the thickness, or gauge, of the steel from which they are made.

I read somewhere that they are 6" in diameter but that does not seem to be the case based on the spacing of the bracket holes to hold it and a picture of what I believe to be an original on an F15. Rough proportioning from the photo of the original would put it at 7" to 7-1/2" diameter based on the 5" between centres of the mounting holes.

I also note from AWM photos "5" ton is the amount shown on a F15A disk. That seems high based on weight of vehicle and cargo capacity. Were different weights specified or did all F15A's get a 5 ton limit?

Thanks for any info. May try cutting out one on the lathe this winter if I can confirm the diameter and thickness. Bolted to a block of wood on a faceplate it shouldn't be too hard to do.

Cheers,

[gjamo]

Jaques be extra careful doing that I have seen some horrific accidents with tradesman doing the same thing.

[Jacques Reed]

Hi Gjamo,

Thanks for the advice. I plan to bolt the plate to the wood with coach screws through the disk mounting holes and also bolt the steel plate outside the circle to the wood so that it does not fly around when cut all the way through. That part is only going to be scrap so a few extra holes in it won't matter. Could see a real disaster happening there otherwise.

Light feeds with the compound slide should do it. Any other suggestions out there?

Cheers,

[Mike K]

Jacques

The method you describe should be effective. I did it once and no problems happened.

I think you might get into strife if you have the rpm's too high . Keep the revs down and feed gently . But as gjamo wrote, things can go wrong .

[Jonathan Moore]

Silly question but why such a high risk process? Why not scribe a circle, roughly cut it out with a thin cutting disk on an angle grinder and then finish to the scribe line with a grinding disk. !0 min job, no bits of metal flying around, no damage to your lathe, body intact.........


Jon

[David Herbert]

I agree with Jonathan, much easier and quicker to do it with a grinder freehand and with a bit of care you won't be able to tell the difference. If you do it in the lathe you will still have to remove the sharp edge with either a file or grinder and flapwheel so some craftsmanship still needed.

Were the Australian bridging disks just flat metal as in the photo above or did they not have a profiled edge like the British ones ?

David

[Private_collector]

Jacques,

I have a disc I believe is genuine item, around here somewhere.

You are welcome to have it, once found.

T

[Hanno Spoelstra]

Originally Posted by Jacques Reed

I read somewhere that they are 6" in diameter but that does not seem to be the case based on the spacing of the bracket holes to hold it and a picture of what I believe to be an original on an F15. Rough proportioning from the photo of the original would put it at 7" to 7-1/2" diameter based on the 5" between centres of the mounting holes.

I also note from AWM photos "5" ton is the amount shown on a F15A disk. That seems high based on weight of vehicle and cargo capacity. Were different weights specified or did all F15A's get a 5 ton limit?

Jacques,

The diameter of the disc is the equal to the aperture of the headlight on CMPs.

The digit on the classification signs does not indicate the the weight of the vehicle, but the bridge weight class:
"The number designated the maximum weight class of vehicles which could safely cross that type of bridge".
Read more on this subject on the excellent Canadian Soldiers website.

HTH,
Hanno


ford3ton.jpg

[Jacques Reed]

My thanks to you all, Graeme, Mike, Jonathan, David, Tony and Hanno,

Your thoughts and ideas are most appreciated. Always good to get different ideas especially when it comes to safety. Most of us are keen amateurs so we don't always have the years of a metal working trade behind us to know all the risks. Much better to take a bit more time and a bit of fiddling around but do it safely.

I had originally considered cutting it out with my Ryobi sabre saw but I have found the blade wanders by 1-2 mm each side of the centre line. This is why the lathe method came to mind. The saw is relatively new and upon inspection I found the blade and holder can be wiggled 1-2 mm each side of the centre position. I found this out when I ripped a sheet of plywood using a bit of steel angle as a guide. I wondered why the cut was serpentine along the pencil line despite the guide.
The saw is good enough for cutting out plywood Santas at Christmas but that is about it. Not much good for an accurate cut. Doesn't seem to be any adjustment like a gib to take out the slack and upon checking other brands at the local hardware store they all have some degree of sloppiness there too. Design requirement or just cheap manufacturing?

So on that note I would be most appreciative to take up your offer of the disk Tony and that way save a bit of work at the same time. (Also keep all my eyes and fingers!)

Thanks too Hanno for that link. Makes a lot more sense now.

Cheers,

[john piercey]

Jaques so did any one end up identifying the canvas?
John

[Jacques Reed]

Hi John,

No, still waiting for an ID on that one.

Forgot to mention in the post that it is 6-'6" wide by 7'-5" long with 2'-9" flaps.

Does that help a bit? Pretty sure it isn't Land Rover but too small for an ACCO. That is why I thought it was maybe a trailer tarp. What else was around in the Vietnam era in Australia?

Cheers,

[Ken Smith]

Good day,
The little AT4 114 Dodges and the AB 120 Inters were around then. I will measure the body on my AT4 when I get a chance.

Cheers Ken

[Jacques Reed]

Hi Ken,

Thanks Ken. Your reply may have pointed me in the right direction.

The attached link to the HCVC shows a IH AB 120 with a very similar top. Not Army, but part of the National Mapping Agency. Perhaps this will help bring out another photo of an Army AB 120. I could not find one during a short Google search.

Cannot say it is exactly like mine but the proportions looks very similar even if the side flaps are different.

It is rather ironic in that my family owned a 1962 IH C120 4x4 Travelall Wagon when I was a boy in the USA. A huge 4 x 4 wagon in its day compared to Jeeps and IH Scouts.

Will look forward to seeing the dimensions of your AT4.

Cheers,

https://www.hcvc.com.au/forum/truck_...-120-4x4-story

[Ken Smith]

Originally Posted by Jacques Reed

Hi John,

No, still waiting for an ID on that one.

Forgot to mention in the post that it is 6-'6" wide by 7'-5" long with 2'-9" flaps.

Does that help a bit? Pretty sure it isn't Land Rover but too small for an ACCO. That is why I thought it was maybe a trailer tarp. What else was around in the Vietnam era in Australia?

Cheers,

The AT4 body is 6'-9'' wide by 7'-3 1/2'' long. I am not sure about the side flaps as my hoops have been cut and modified to make a little cattle crate by the previous owner. The original canopy had been taken off, folded up and put under a bench when the truck arrived at the farm. It had been offered to the truck wrecker who I bought the truck from, but he didn't take it as he thought nobody would want it.
But yours is close enough for me to say, if you ever want to sell yours please let me know.

Ken