What were the large frame engineers thinking in the '50s

They pulled power off the top of the center section for the Electrall as shown.
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On the bottom side of the center section, it is curious that the cover has nearly the same bolt pattern as a SAE 6-bolt PTO. One axis is off by 1/8" as shown by a truck PTO gasket laid over the tractor IPTO cover plate. It would be no problem to order truck PTOs with the altered holes. Someday I will probably re-drill a SAE PTO to do just that. A 4" gear or sprocket attached to the IPTO coupling has enough clearance inside the tractor center section. I can't see why the cavity is so large. It could have been made smaller and added strength to the center section.<a href="http://s140.photobucket.com/albums/r16/Wardner/?action=view&current=W-400043.jpg" target="_blank"></a>

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This is what it might have looked like. The nice thing about SAE PTOs is that they are all shiftable and some have two speeds.
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This my current solution. It was alot quicker than tearing apart the tractor and finding the right gear combos plus setting up the correct gear lash. It is Balanced Head Mower drive chain driven from the rear PTO that is routed underneath the left axle with a shaft.
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So the question is: Did IH plan on attaching an off-the-shelf PTO under the tractor?

I can believe they might have driven it from bottom, however this would have limited the interchangeability as the H-300-460 had a standard belt pulley mount, they took the same mount gasket, same goes for M, SM-SMTA, 400/450, & 560 all had same opening and matching gear internal with same mount flange gasket, probably cost was factor also as the gear access from the bottom on H/M-SM was not there. I worked for IH then CASE-IH dealers for 47 years in service & parts.

"I can believe they might have driven it from bottom"

Driven what? That is a key question. Were they thinking that specialty harvestors might need another PTO source? Were the companies that built bituminous pavers from tractor frames using that opening? Did the 3/4 swing small shovels need something like that. Did any of the competing tractor manufacturers furnish a bottom PTO for front PTO implements and IH was ready to match them.

As for cost, it makes no difference on low production specialty applications.

As for H, SH, M, and SM not similarly equipped, so what. They were history. None of them had IPTO either.

That is not correct to think that the H-M-SM wasnt important, they were still very prominent on farms here in the midwest in the 50s. SMTA had IPTO. Front IPTO wasnt used for anything in ag equip much then or now. Remember ag was far more important to IH than Industrial or construction, it was a sideline that they would adapt ag tractors to suitable use in other ways. Compared to JD available in that time frame they were light years ahead.

There probably wasn't a demand for a front pto in the US. IH in Germany did provide a front pto on the German built F-12 and the later DF-25. Their later 3 and 4 cylinder tractors all had a mower drive driven from the bottom of the gear-box as did the 2 cylinder tractors from 1958 onwards.

Sure, the previous tractors were important and Case IH still supports those products with parts and service. But time marches on and new products become the focus point. If it didn't, we would be stuck with Titans and Moguls.

I included the Electrall gearbox as an example of a limited production item that IH pioneered at that time. The phrase "if you build it, they will come" didn't work out so well for that concept.

So I am wondering if the underside PTO was actually a concept that the engineers were thinking about but it died on the vine. Personally, I don't think the shape of that opening was purely conincidental with the shape of the SAE 6 Bolt PTO. It was drilled slightly different so that the market would have to buy IH product that IH could buy cheaply and mark up substantially.

But more to the point, that opening would/could expand the versatility of the SMTA and later models. Just wondering if the concept of the underside PTO ever saw more development during that period.

Doesn't look like anyone here can comment on that except Athol Carr who indicated that front PTOs were available in Europe. Now there is a good reason why IH might have been testing the waters over here.

Our 656 (and probably its newer brothers thru 686) looks alot like that underneath as well. It would be interesting to know why it is that particular design and it was kept that way til the end. I had to get into the clutch housing a year ago because of a needle bearing on pto shaft failing. An insert also had to be machined to repair the casting for the bearing. I got way more familiar with the housing than I wanted. I seem to recall that while the cover in that shape provided good visibility, it really did not improve repair access--I believe the repair almost could be made if the casting was solid in that spot. Being you have the spare casting to play with, maybe you could check that out for me/us--see if you could reverse engineer the casting from the mold to final assembly without that hole. There has to be an original intended purpose for it, even if that idea never materialized in regular production.

As far as a standardized part almost fitting, that seems to be par for the course in agriculture and automotive until a standard is created and finally adopted (forced?). How many times have we encountered parts that almost fit or look the same until you measure or try to install? It sounds like the HD truck world seems to be the best standardized--how are construction and industry in that regard? Could you imagine a world where everything was standardized? You could bolt a SAE bellhousing deere powershift rear to an IH SAE bellhousing pattern engine or put a tractor engine in your chevy caprice.
There are likely plenty of arguments for and against standardization but when "almost the same" is within an eighth of an inch the same you wonder why bother.

The parts diagrams for the 74 thru 84/85 series world tractors show a side/front pto assembly (i dont remember if it's for MFWD or implement PTO however). Once tenneco comes on board they changed that design...
We should spend some time looking at euro/aussie case parts pages of similar designed models to the classic farmalls.
I also remember when in elementary school looking at the school's deere and it had a pto shaft at the mid point either facing sideways or forward. So Ih is not the only front pto contender.

always learning
karl f

Thanks for the response Karl. There is hope for this thread yet. It sure beats "What does my tractor weigh?" and "How much is it worth?".

I can't remember how vital that opening is for assembling the IPTO parts. The design allowed them to use a seasonal disconnect through the wide part of that plate. It was phased out in a couple of years. The seasonal disconnect was probably an afterthought when they realized it could be done because they had the opening. I doubt if that hole was created expressly for the disconnect. It turned out to be a lame idea.

Its interesting that they made another big hole on the side of the housing with the 560 hydraulic pumps. Perhaps that killed the bottom PTO idea. Too much power coming off that shaft and bearings.

I'll have to look at a 06-86 medium sized tractor next time I see one.

The SAE bell housings had to come about because there were beaucoup engine builders selling there products to even more truck mfgs in the early years. Many were "assembled" trucks coming from factories that didn't build engines. Some were divorced engines similar to Oliver tractors but what works in a rigid tractor frame is not so good in a flexible frame truck.