So one of the things i learned from THIS project, out of all the projects i've ever done.. THIS project finally made me realize i do dumb things when i work tired. This project happened during an extremely busy time in my life, which is why it took a year (with long breaks in between bursts of progress), why it mostly happened at night, why i forgot to take pictures of some things, etc etc.
So i cut these pieces of angle iron to use as braces, a total of 4 pieces, 2 for each side.
So what's the problem? Well, when i went to weld them on i must have spaced out, and installed them 'facing up', i.e. i turned them into little cups which would collect water. That annoyed me, so i drilled drain holes through them and then cut MORE triangles (just flat stock this time, not more angle) and then welded those over top to make 'box' sections. Except that with my slight lack of fitup skills and patience, it ended up looking like hot garbage compared to if i had cut whole box sections in the first place, or if i had just welded the angle iron on facing downward like i should have done from the beginning! Ugh. So, whatever. It's a bit ugly.
And... now i cant find a single pic showing them installed? Idiot. Im gonna drive to my buddy's house at some point and retake all the pics that somehow went missing, but for now here's a truly terrible angle i snipped out of a different pic, sort of showing 1 out of 4 installed braces.
Right.. onwards..
One of the things i didn't like about how this backhoe operated was how 'loosely attached' it seemed to be to the tractor. You sit on the tractor, but operate the hoe, and you can feel all kinds of relative movement between the two pieces, and it irritated me. Part of improving that was welding up the divots in the round tube which engaged to the brackets on the tractor. You can sort of see that interface here:
Remember that one of those notched brackets was missing when the tractor was purchased? Well, when i went to install it i realized i had an appropriate bolt but no appropriate nut. Funnily enough, it turned out the cheapest nut for that thread size which could be had with 2-day shipping on Amazon, was a coupling nut, in other words a very deep/tall nut. No problem, i thought, ill just chop it in half on the chop saw and have matching nuts for both sides! Then i got lazy and left it exactly as you see it, with the odd looking mismatched hardware.
Anyway, i didn't like all the slop in the tractor-to-backhoe connection, and filling in divots on the round bar wasn't enough to be rid of it. So, i decided to invent a sort of 'top link' which would preload the subframe into its notches just enough to get rid of the slop. Many subframe backhoes have something like this anyway, but this design had nothing.
Spitballing the layout. This space is actually pretty tight on such a small backhoe, with the tank/control tower assembly, oil filter, and pto pump all fighting for space here. But it would work. Now, this is opening a big can of worms of possible discussion because it relates to 'why do 3pt backhoes (with careless/unknowing operators) break tractors and subframe backhoes don't'.
Basically, when you dig with a backhoe, your downward force on the bucket is an upward force on the 'base' of the backhoe, which gets transferred to the rear of the tractor as a lifting force. If you lift the back of a tractor, you put the entire underside of the tractor in tension, and the topside in compression. The tractor has near-unlimited strength in compression, at least in this context. But, in tension the only strength holding the tractor together is the various bolted flanges between sections. These are usually cast material (brittle), with only bolt heads or perhaps small washers transferring all the tensile force into the flange (high local loading), and the bolted flange itself is usually cantilevered to some extent, meaning if it's allowed to deflect at all it will create another bending force where that flange 'turns the corner' to the body of that housing, etc. This is where the failure will start that leads to broken tractors.
A subframe gets around this by putting the force into the tractor differently. You can imagine it similarly to you being a wounded soldier needing evacuated. If you are laying on the ground and someone simply picks up your feet, your body will flex in the middle unless you exert great strength to stop it. One side in tension, one side in compression, yadda yadda. However, if someone puts a
stretcher under you and picks up one end of that, you will flex much less because the stretcher has its own structure to take that, and you mostly experience a straight up lifting force. The subframe does that for the tractor.
So the reason this top link thing is relevant to that 3pt backhoe vs subframe backhoe thing is that if you preload it the wrong way you go right back to putting the whole bottom of the tractor under tension. Now, the subframe would probably still prevent the 'broken tractor', but in my mind theres a 'better' way to preload this top link thingy, and a worse way. Point being i had to think about all this before deciding whether a theoretical top link design was actually a good idea. I decided, for myself anyway, that it was and continued on.
Now to turn a chunk of black pipe into a top link. It needed to be adjustable. I had a cheesy cat0 top link which had bent enough that it wouldn't thread any more, which i had already cut the ball ends off of and welded them onto something else. In this case i don't need many inches of adjustment as a 3pt top link would.. just maybe ~1/2" or so to take the slack out of the subframe/bracket interface. That's 1/2" of travel in this link, not that the subframe/bracket interface has 1/2" of slack, mind you. So, i simply chopped off the section of thread that was bent and would have been more trouble than it was worth to fix, straightened the rest 'enough' in the press, and had myself a big ol turnbuckle thingy.
Since this tractor project was essentially a 'test run' of a bunch of things i would like to implement again elsewhere, one of the things i did several times was add grease fittings to things which previously didn't have them. So, i drilled holes in the threaded ends of the turnbuckle center section.
These holes don't need to be very big because grease gets pumped around at very high pressure just by the hand pump on a grease gun. It will flow through almost any gap. So, a fairly small hole. The tube itself is not thick/deep enough to take the threads of the grease fitting, but the simple fix for that which i used many times on this tractor, is to simply weld an appropriately threaded nut over top of the hole. Usually this is because the hole is damaged beyond easy repair, but in this case it's just because the material beneath is too thin to be threaded. I used 1/4-28 grease fittings everywhere on this thing, so 1/4-28 nuts is what this takes.
Insert disclaimer about welding over Zinc, etc etc. Nuts welded on, fittings inserted.