Am Mittwoch, 18. Oktober 2017 02:25:49 UTC+2 schrieb :
That is one of the things I do not like about the plans I have. Some places
look like they would be big stress concentrators.

You're welcome to post your sketches here. I'll take a look (send me an e-mail if I don't) and others can give their opinions too. You won't get a detailed analysis, but we can likely help you to avoid the worst stress concentrations.

Get a two-lever valve block if you can (these are available second hand.)

Not sure I understand what you are saying. There are four hydraulic cylinders so one needs four valves. Are you saying use two two lever valve blocks instead of a 4 valve block?

No, I mean you could get one of these (valve block on the right):
https://www.flickr.com/photos/138493...posted-public/

The two big levers operate four spool valves (the small levers in the centre are to raise and lower the stabiliser legs). You can see the tops of the valve spools in the pictures.

That's my own pile of backhoe spares and the block is going onto my machine soon (to replace a leaky block), so it's not for sale, but they are often available from places which stock used backhoe parts. Two levers are a lot more comfortable to use than four levers.

The idea of the bell crank and foot pedals definitely sounds possible. One backhoe manufacturer used to have some arrangement like that, but it wasn't a manufacturer I'm familiar with. Might have been Case.

One last thing: if you're going to use the machine a lot, think about pivot wear. Use large bearing surfaces, lock the pin so that wear only occurs at one interface, and maybe consider replaceable bushes.

Nice project. Enjoy it!

Chris