backhoe question

[Blumoon]

I am looking to build a backhoe for my old minn. and after looking at all the super fine ones on this page, I have most of it figured out except, is there a predetermined distance or rule of thumb when spacing the distance on the jib boom pivot pin and where the cylinder pins in. Never have found anything about that. thanks

 

[welderboy14]

Hey,
It would be helpful if you were to post a pic of what you are building the backhoe for.

 

[Blumoon]

The back hoe is going on an old 1953 RTI 100 minneapolis moline the mounting to the tractor is all done, was just wondering about the spacing where the jib boom cylinder mounts and the pivot pin go, what the distance should be. I'v measured all kinds of hoes {case, ford, JD, Inter.} all seams to be different. Might have to make a S.W.A.G. thanks

 

[Brad_Blazer]

It's all about range of motion vs. available force considering mounting points and cylinder travel. On mine the cylinder is mounted under the boom and forward of the boom pivot so if you drew a line through the pivot points it would be about 20 degrees from vertical. Mine also has a crook in the boom. If you make a straight boom that line would be closer to vertical.

You can look up specifications for backhoes that show the entire range of motion. That is a good place to start. If you're not going to use an existing design you will need to model your design somehow. Some like cardboard models, some prefer doing it on paper or with CAD. I even made a spreadsheet to calculate force and range of motion for a grappel that would work with any hydraulic member. Bottom line you want to have a good design for the whole thing before you start cutting and welding.

I learned my lesson when I tried a swag with my stabilizers. They work great except they don't retract as far as they should. It's still on my list of things to fix.

Brad