Gordon_M

even if you have a thread with the same TPI but it is not an APT union it will not seal. Pete

 

That's one of those "almost, but not quite" things Pete.

If I remember my thread history, NPT is basically the same thread size and pitch as UNF, and was designed originally to seal either against a tapered NPT or a parallel UNF thread, of course it prefers the NPT.

As an example, think about the headless bolts on the Dodge rear springs. They are fitted with NPT grease fittings, but the extractor tool is a plain UNF thread of the same diameter - you just screw it in till it jams then rotate the bolt out.

All the tapered pipe fittings on the GMC or the Dodge will be NPT I think, with one silly exception. On the civilian-style oil pressure gauges the thread into the back of the gauge itself is some oddball non-NPT thread. The absolute best source for all this info is the ORD 7-8-9 Parts List for the vehicle, where all the thread sizes of hose, tube, and fittings are laid out plain and clear.

I'd contribute if we had a way to do it.

looks like the truck would fix - except maybe the cab

Well if you are thinking DUKWs and the RAF, perhaps I could mention Sunderlands, Catalinas, and anything else wet and winged ?

Standby crash rescue, any number of functions

Almost ....

How about a tool for pulling out reluctant driveshafts / halfshafts on a disabled vehicle to allow it to be towed on its wheels after, say, a transmission, differential or even halfshaft failure?

If you really want to experience this, you need to hear the 1958 original;

Gerald Hoffnung's letter from a Bricklayer to his employer, requesting sick leave, from his unforgettable address to the Oxford Union.

( and yes, I am old enough to remember this, though I wasn't there )

Try it quick then cancel the auction - though to be fair I always thought the Ferret driving position was rubbish compared to the Dingo which was a delight to drive.:blush:

Interesting it doesn't have the day, but I expect it didn't stop moving all the way from the line till the time it was issued.

Pictures, Mark, we need pictures

( and welcome, too )

Eight to twelve weeks at a guess.

Another interesting comparison would be the difference between the Build Card date, and the Date of Delivery on the glovebox plate.

Early on there could be substantial differences in those two times, but by August 44 I'd expect ordnance inspectors were checking the vehicles down the line and accepting / stamping them virtually the same day.

Nice machines.

They don't really exist here any more. Any that did come over were just worked to death, resurrected, then worked into the ground again.

Same could be said for most of the 4 x 2 trucks really, but they lasted even less time,having to work on freezing, salted UK roads.

Being chain drive the army was not keen on them Thanks again, Tom

Go on then, for us non-bike people, what's the alternative to a chain drive please?

I remember Bob James got hit in his DUKW in a very similar situation.

Has to be said I wouldn't like to be in the cab of an artic that rear-ended a Scammell at speed either, even with a living van as a cushion. :-(

Clive only makes them this easy once in a blue moon ....

Welcome, and here's a thought to carry round with you - wish I'd had it years ago.

There is a danger here that you will bypass something really worthwhile that you get a chance at, just because it isn't a Scammell or even the exact model you want.

Have a good hard think about everything you run across, especially everything that is rare, or odd, in case you regret it down the line.

If you do find something odd you don't really want, be sure to mention it on here, and one of the others will tidy it away.... :angel:

Ta, will see if I'm in Aberdeen that weekend.

Aha, CMO 157.5 then.

I'll guess it only had four wheels on it. That would make sense if they were assessing traction or floatation.

( If it has a diesel in it instead I can't tell from here ...)

Didn't have to watch it Clive, neighbouring block was broadcasting, cheer by cheer... only vague military connection I can recall was recovering three jeeps from a mushroom farm near Dunblane some years back.

Got any more images of that trial?

Ah,

well if they had been pitted against Andy Murray they'd have come second

Um well Gordon a Saracen actually. Two of them but taking it in turns.

Cor, that's terrible :blush:

The whole test method should be built round applying the load in a measurable, constant fashion - having an Aussie driving a Saracen would give only very approximate results, you'd be far better off with a Diamond T and using the winch.

They probably had to use two, as if they were trying to load it evenly it would heat up the convertor in the poor Alvis quite notably, followed by that burning brake band smell, so swap to the other unit to let the poor thing cool down.

Can you tell if the Saracens had improved cooling - conventional or reverse flow - clouds of steam from the engine compartment or smoke from the transmission? :undecided:

Yes well done Gordon the thing under the number plate is indeed an Amsler Load Cell

Ok that is the apparatus. What might be on the other end?

Just a big winch, really. You wouldn't need anything special, like a vehicle with a dynamometer or whatever, in fact the last thing you'd have at the other end would be a moving vehicle - possibly a winch truck with ground anchors.

Going further;

the test weights on the back of it just simulate the body weight. You would probably do this numerous times on numerous surfaces, and repeat with larger weights to simulate a full load.

On a dry surface you might get wheel slip due to less than 100% braking efficiency and that would take us back towards my original guess. On mud and earth, given army truck brakes, I'd expect the wheels to be pretty much locked.

Other test equipment you might find on it would be stuff like a pressure indicator / recorder on the hydraulic or air braking system, which would tell you the braking force that had to be applied to achieve 100% lock.

Amsler is now Roell-Amsler and they still make test equipment such as this impact test machine - image from my day job about ten weeks back. As I said, dangerously close to my day job.

Go on, tell me I'm wrong and there is some huge technical thing at the pulling end too ?

For one reason or another I never got around to updating this, but as the second event will soon be upon us I had better put up some pictures from the first on.

Oh, go on then, tells us where and when for this year ....

I haven't got any trucks in this area but may be able to nip down from the day job.

I await the accurate answer with interest :angel: though from that photo it looks like it is still doing the same job, just measuring wheel slip under braking rather than driving - still a wheel slip indicator, with the thing under the number plate being a load cell.

Worth pointing out that if you winch the truck forward with the wheels locked and the thingy turning - it is still measuring wheel slip on the given surface, it's just 100%

Gordon what is an ACCO?

 

Yes one of the functions of the contrivance is to measure distance, others said it was a speedo but its not a speedo.

 

I think you are nearly there Gordon can you just clarify your answer please.

Now you are asking Clive ....

ACCO = Australian Constructed Cab Over, basically the Australian locally-built replacement for the Canadian CMPs that formed the backbone of the Australian Army during WW2.

http://www.mapleleafup.net/forums/archive/index.php/t-514.html

Basically distance travelled by thingy, MINUS distance travelled by front wheel, OVER, distance travelled by thingy, Divided by a hundred, EQUALS percentage wheelslip of the driven wheel.

Dangerously close to the day job again.

It's fitted to an ACCO under test, and the only function of that sort of flimsy contraption is to measure distance, but apparently it isn't to measure distance, so ...

On a test vehicle, under load, it measures distance compared with the distance travelled by the front wheel over the same time, to give a reading of wheel slip under load.

Basic job looks absolutely tremendous, well done

( I'm hoping the hideous modern number plates are on with wing nuts ) :cool2: