Farmall Cub

I'm doubtful that IH would design a mounting frame that isn't stronger than the tractor can pull, but I want your thoughts here before I do anything dumb. Should I be concerned about attaching an implement to the universal mounting frame, that uses most of the power of the tractor? Especially with no shock loading, I'm guessing the tractor would die well before the front casting broke. The universal mount itself is also a concern...those pieces at the ends of the lift arms don't look too beefy.

I don't know if this would actually max out the Cub's HP, or if I even want it belly-mounted anyway, but I'd just like to know if I should be concerned about this sort of thing.

Thanks,
David

Perhaps a better explanation of what you want to do would yield better advice.

David:

In 12 years I have never had a concern with the UMF. I am not sure what concerns you have about the UMF - it is rather robust and will handle any implement that IH designed for the Cub. I have used certain sections of the UMF with my old snow plow setup and it was very heavy but posed no problems at all for the UMF and the hydraulics. I am curious about why you are concerned about belly mounting any IH implement or IH approved implement. Can you clarify?

Check out the Cub Implement Manuals. Manuals such as the Cub-144 Cultivator show the UMF and it's mounting instructions.

I would think it would handle any kind of steady pull, but if it was under a hard pull and got a sudden shock,such as catching on a rock,etc. it may be hard on the front of the tractor, primarily the casting where the frame mounts, or the radiator casting.

Fundamentally, I think the mounting frames are plenty strong enough, at least for what IH intended them for. But there are conditions you need to think about if you are making someting yourself or adapting something that wasn't originally intended for a Cub. Another factor to consider is how worn they are. I have seen plenty of them broken and welded, usually at the beam brackets (at the front end of the round gang beams). These same ones are usually a loose fit. Any looseness magnifies the effect of sudden shock (as John mentioned). The bolts on the bottom of each beam bracket can be tightened to remove the looseness, as can the bolts on the front of the tool bar clamps. Keeping these maintained goes a long way towards avoiding breakage. Some are worn enough that tightening the bolts won't take the slop out. A thin sleeve might be a way to tighten them up. I've never tried that but If I was going to use one a lot, I might give it a try.

Originally, the most common uses for the mounting frames were for cultivators and planters. For the cultivators, most of the groundworking tools were either spring mounted, spring trip or friction trip so they would give if they strike something. Ones that were simple solid mounts were expected to be used at slow speeds. Example like this are the knife weeders, ducks foots etc. used with small vegetables. If you use a tool bar type implement, you have to be concerned about how wide you are working. In normal operation, you will have essentially even force back on both mounting frames. If you slam into a rock out on an end of a tool bar, you not only have added force (with leverage) back on the side that hit, but the opposite side will be slammed forward. Combine that with some worn/loose frames and you have the perfect storm for a broken beam bracket. So going wider means going slower.

By the way, my cultivator comments also partially apply to the planters. The runner planters have a knife that will ride over most obstructions. The lister type opener of the blackland planters has a built-in friction break for when it hits an obstruction.

So my answer is that it depends on just what you want to use and how you do it. A little judgment plus a little maintenance should keep you out of trouble.

As Jim said, they're pleanty strong enough for what they were intended, and it really depends on what you're thinking.

From an engineering standpoint, the attachment points on the tractor, and the arms themselves were designed for a certain purpose, and they all seem really strong. They are designed for a certain vertical force (up/down) which they seem way over-engineered and much stronger than necessary. They were also designed for a certain horizontal or lateral force (side to side). This one gets really tricky and would be hard to determine how strong the attaching points really are.

If you're thinking of modifying them to use for more lifting or engaging power, or where you are applying more vertical force UNDER THE TRACTOR, then I would not be too concerned.

If you're thinking of modifying them to pull way out at the ends of the arms, either lifting something heavy, or applying a lot of force right at the end of the arms, then I would be very cautious about it. The farther you are away from the attachment mounting points, the more leverage you have, and the easier it would be to break the tractor itself at the mounting points.

Think of the cheater pipe you add to a pipe wrench to loosen a fitting. Yea, it works and even works really easy, but it's also really easy to bend the pipe wrench. Start putting too much leverage on those cast iron attachment points and they won't bend, they'll just break.