The Fordson Tractor Pages Forum

Hello,

I know this will be a tricky question, but at least it's orange.

Does anybody know were the letters HD stands for at the track tractors from Allis Chalmers?
The U was for United, the M for Monarch, the W series came from Rumely, and there one types were alphabetic as A till F.

Hi Henk,
I think that AC bought another company's line of crawlers at some point. I can't remember which company right now. I'll try to find the information again. That might give a clue to where HD came from.

JC

Hello JC,

They bought the Monarch comp. and the first crawler was the M from that stood for Monarch. I don't recall that they bought another crawler comp.

Henk,

I have done a little research on this and it seems "H" was the designation of Alliss tracked machines, "D" indicates diesel and "9" indicates size.

I don't know if this is compltely accurate but it seems a reasonable explaination from the information I have in books on US tractors.

I still can't find the information I was looking for about HD's. On Internationals (since we know Brian has a soft spot for them!) TD-9 meant Track, Diesel and 9 was the size. WD-9 was, Wheel, Diesel, 9. Gas powered ones were T-9 and W-9. I wonder if the "H" in the HD meant something or if it was just a model designation.

Hello,

It could be that the H was the next letter in the alphabet. The wheel tractor ended as I recall at F, so H could be the next one. I knew already that the number has to do with the size of the plough. So 9 would be a 9 bottom plough. The D could mean Diesel.
Please keep searching.
I'll try the forum that Brian told me about.

Henk,
There was an Alliss G!

That was the little tiny one that Dies had last year. The one that looked like a bent pipe with an engine on the back.

Your right Brian,

The HD was there before the G. Forgot all about it.

OK Guys,
Here's what I can find, please check yourselves for verification...

Allis Chalmers started to produce tracked machines. Their big 'claim to fame' was that they came up with a design of tooth for the drive sprockets that dramatically cut down on wear.
They decided to call this design 'Hunting Tooth' and so, all of their crawlers were given the prefix 'H' for 'Hunting Tooth' drive sprockets.
They also offfered the choice of Gasoline powered or Diesel powered so...
H6 = Hunting Tooth drive sprockets, Gasoline powered.
HD6 = Hunting Tooth drive sprockets, Diesel powered.

That's deduced from a 'crawl through' on the web. (Oh! the guy's a comedian as well

What is definate is that 'D' is Diesel and no 'D' is Gasoline.

What was deduced, after MUCH reading, is that the 'H' denotes this low wear 'Hunting Tooth' design on the drive sprockets.
Reasoning - Can't find ANY 'H' prefix before they announce this low wear sprocket design, then they give it the marketing name of 'Hunting Tooth', then the 'H' prefix starts to appear.

Could be wrong, please check.
Must go and sit on my Major now, all this talk of others makes me feel quite poorly.

Mike

Thank you Mike,

Just take a look at a picture of your Major and you will feel well again.

Your story seems reasonable, for I found out now the Hunting Tooth was a odd numbered wheel. So every two turns the same teeth was in grip. That means half of the wear.
The only thing I'm wondering. Is Hunting Tooth a name that AC came up with or was it a common name before it?
Something like Baco, that stands for the adjustable tool.

Henk,

It looks like they just came up with the idea of using Hunting Tooth on crawlers.
If you Google "Hunting Tooth" you will find pages on this type of gear set. Rolls-Royce used them in the Merlin aero engine, so have many others.
The idea is that one of the gears is based on a prime number, so that it will not exactly divide into the other without a remainder. This ensures that no two gear teeth always mesh together, reducing the possibility of localised damage or wear.

Mike

The other place you will find that type of gearing is in Dexta timing gears. That is why it is easier to take the gears off to line the marks up rather than try and turn them all into line.

Another line of though. Allis took over the Monarch crawler tractor and built a small petrol model "H" to begin with. Is it possible that Monarch had been associated with Holt of crawler fame and the "H" denotes this?

Brian,

Seems a good explanation, but at the same time there were the Monarch Model F (1926-1931)
Monarch Model G (1926-1927)
Monarch Model H (1927-1931)
A later model H3 was build from 1960.
I'm still trying to come on board at the forum you gave me, but so far no luck.