Toy building #5: The Concrete Pump - The boom

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Blog entry by johnstoneb posted 12-08-2015 03:38 PM 1460 reads 0 times favorited 4 comments Add to Favorites Watch
« Part 4: The Concrete Pump basic truck Part 5 of Toy building series Part 6: The Concrete Pump - The Hydraulics »

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

4 comments so far

View JoeinGa's profile


7741 posts in 2610 days

#1 posted 12-08-2015 03:48 PM

This thing is really starting to take shape. Thanks for sharing, I enjoy following along

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View Monte Pittman's profile

Monte Pittman

30505 posts in 2941 days

#2 posted 12-08-2015 03:50 PM

Very impressive

-- Nature created it, I just assemble it.

View Dutchy's profile (online now)


3508 posts in 2771 days

#3 posted 12-08-2015 06:51 PM

A lot of construction work. I like to follow the building and I’m curious what is coming next.


View crowie's profile


3368 posts in 2554 days

#4 posted 12-08-2015 09:02 PM

Now that looks the deal Bruce…A HUGE WELL DONE SIR...Thank you for all the detailed notes and extra build photos, much appreciated….

-- Lifes good, Enjoy each new day...... Cheers from "On Top DownUnder" Crowie

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