It’s time to get serious and finish this. The boom will make or break this build. I drew this up on Sketchup and animated it everything bends properly and seems to have the clearance needed. The boom is a little complex The first three sections only have to fold out 180 degrees. The 4th section has to fold around 245 degrees and the fifth section has to go 210 degrees. There are some linkages that have to be made for hydraulic cylinder clearance. The 3rd section has an offset so the 4th and 5th sections can clear the first section when stowed.
Like all plans as I start building i come up with different ideas so there were some on the fly changes.
This is the 2nd and 3rd sections. Both ends of the 3rd section have been changed from the original design. The changes allowed me to use nutserts and flathead screws instead of crown nuts and though bolts. Cleans up the design and less to hang up on.
3 sections installed and pinned loosely everything so far seems to fit.
Everything folds and seems to fit.
This is section 4 glued and clamped. While working with this section I noticed I had some very short grain on the pivot ends of most of the sections. I decide they needed strengthened. I laminated 1/16” plywood on the inside or outside depending on clearance. I think that will strengthen things enough that the boom won’t break off in use.
Here is the boom all 5 sections pinned or loosely attached everything folds the way it is supposed to. I tried to get a picture of this unfolded but it was kind of like trying to push a chain. I’ll get a picture after the Hydraulics are installed.
On to the hydraulics.
-- Bruce, Boise, ID