Case D100 backhoe

[Eugen]

I would be worried that the cast iron will snap when tightened. I think that a sandwich of plates, even welded together to get the thickness you want is better. I also think that 0.010 is too little to provide enough clamping strength.

[thebuildist]

So I'm hearing this group say that the u bolts are the way to go.


Check.

1/2" u bolts are not an option, for this reason: off the shelf they don't make 1/2" bolts in the "2 9/16"/"2 5/8" spacing that I need. You can get them custom made, but those are more like $100 for 4 of them.

So I could do the two 9/16 like I mentioned. But at this point I'm inclined to just do single 5/8 u-bolts on each side. I'm a little concerned that doing two sets of 9/16" holes in each set of collars might actually weaken them a bit. Balancing that against a single 5/8 hole, and believing that the single 5/8 bolt is more than strong enough, makes me inclined to just install a single 5/8 u bolt on each side.

And attach the center of the crossmember to the differential in the center. (probably I'll weld a tab or two to the 3pt hitch backing plate, which is well-attached to the differential)

And do the final machining after the split has been done.

As of now, unless I hear good arguments otherwise, that's my plan.

And thanks, everyone!

Bob

[thebuildist]

I would be worried that the cast iron will snap when tightened. I think that a sandwich of plates, even welded together to get the thickness you want is better. I also think that 0.010 is too little to provide enough clamping strength.

By .010 being too little, do you mean that I should machine the collar to more than .010 undersize? You think I chould machine it .015 or 020 undersize?

Like you, I am concerned about the cast iron under that kind of clamping force after I've cut away 20% of it by drilling two big holes in it. But cast iron is pretty darn strong in compression. So I think that if I limit myself to one 5/8" hole, that it'll hold.

And I can't wrap my head around how to weld the stacked plates together. All I can do is weld them around their outer perimeter. And where the collar contacts the axle housing I think it needs to be seamless/solid.

Is there a way to think about it that I'm missing?

Bob

[JSinMO]

@thebuildist Sounds like you have kinks pretty well worked out. not sure if this will be helpful but I took a couple of photos of the mounting plate on the back of my 648. My subframe bolts to the center of the rear end.

Looks like your planning is well past this point but I thought it couldn’t hurt to have a look!

[thebuildist]

Thanks, @JSinMO !

I really appreciate all the info I can get!

Bob

[Eugen]

By .010 being too little, do you mean that I should machine the collar to more than .010 undersize? You think I chould machine it .015 or 020 undersize?

Not the machining of the bore, sorry. I meant the distance between the two halves once you put them on the axle.

Like you, I am concerned about the cast iron under that kind of clamping force after I've cut away 20% of it by drilling two big holes in it. But cast iron is pretty darn strong in compression. So I think that if I limit myself to one 5/8" hole, that it'll hold.

And I can't wrap my head around how to weld the stacked plates together. All I can do is weld them around their outer perimeter. And where the collar contacts the axle housing I think it needs to be seamless/solid.

Is there a way to think about it that I'm missing?

Bob

I'm in a hurry to leave home now but I'll come back with a drawing.

[Eugen]

Excuse the poor drawing

[thebuildist]

I do have to admit that I hadn't thought about it that way.

I'm going to have to think about it for a little bit. The hole in the middle needs to be about two and 9/16. And the steel that I am working with is 4 in high. So if I split a single piece of steel down the middle into upper and lower collars, then the thickness at the very top and very bottom of the colors will be just a smidgen over a half inch. The cast iron I have is just a big 2-in thick plate. So I can kind of cut out whatever shape I want out of that. And I was going to have the collar be a minimum of 1 in thick all the way around.

So my choices are to go with cast iron with a full 1-in thickness around the whole perimeter.

Or use the steel plate with a single joint in the center line of the collar thickness. I can see how that single vertical joint running front to back shouldn't present any terribly big problems strengthwise. It might be a bit of a challenge to drill the holes for the u-bolt because they'll be going right down that seam line. But I could probably figure it out.

And if I do use the steel plate I can either consume 20 inches of the 1x4 bar, two pieces of bar for each side, and have half inch thickness at the top and bottom.

Or I can consume 40 inches of the 1x4 bar, four pieces of bar for each side, and have for 1 in thickness at the top and bottom.

I'm trying to get away with just buying a single 12-ft stick of the 1x4 bar. It's $200 per stick and I'd hope to just buy one of them. But if I do have to buy a second one it's not like I'd have no use for it.

And I don't really know where I'll be getting half inch bar. I'm getting the 1-in bar for about what you normally pay for half. So maybe I'd be best off not using half anywhere and just buy two sticks of 1 in and use it for the whole project.

I'm going to have to think about this.

[Eugen]

Another piece of bar top and bottom can be welded to make it thicker.

More to think about. Also, consider what is $50-$100 extra for something you want to use many years.

[Harry]

Bob, you mentioned cast iron. I would think cast iron would be harder to work with than steel. Harry