Toy building #6: The Concrete Pump - The Hydraulics

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Blog entry by johnstoneb posted 12-10-2015 05:00 PM 743 reads 0 times favorited 2 comments Add to Favorites Watch
« Part 5: The Concrete Pump - The boom Part 6 of Toy building series Part 7: The Concrete Pump - The Finish »

Hydraulics-I have a 4 yr old grandson not only uses the word but knows what they do. So this boom is going to need hydraulic cylinders.

I did find on my camera a picture of the boom assembled and somewhat upright and extended. No place to extend outriggers so that’s all the extension you’re going to see.

For the cylinders I decided to use various sized dowels. The first cylinder was to be 3/4” barrel with 3/8” shaft. I thought I could drill the barrel on the drill press. The 3/4 dowel was drilled and I got it close enough that I could use it. It was a little off center and not quite straight. The 5/8” and 1/2” barrel were going to be too small to use the drill press.

Once the barrel is drilled and the shaft is cut to the right length I drill a piece of 1/16” ply and place it on the shaft then glue another piece of ply to the bottom of the shaft. Once the glue is dry I sand the piece on the end of the shaft round and small enough to fit in the barrel then glue the top of the barrel on making sure the shaft stays free. I think this clamp is a little larger than necessary but it allows me to have a cup of coffee waiting on the glue to dry and then I get my bench back. Then I sand the top of the barrel round.

Time for the smaller cylinders. I bought a Supernova lathe chuck and a keyless drill chuck about a year ago when my Woodcraft had a sale on them and hadn’t uses them yet. Time to learn how.
The first barrel needed to be about 7” long I thought so chucked up a 10” piece of dowel. I knew this before and the lathe proved it. Dowels are not always straight. That did not stop me. I found the center shove the brad point into it and turned on the lathe, proceeded to feed the bit into the dowel. Pulled the dowel off and it was obvious that I needed more support on the dowel from the chuck jaws and that I should avoid contacting the turning chuck with the extended bit. Off to Woodcraft to see what they have in the way of chuck jaws. Pen jaws work and will chuck down to about 3/8” dowel.

With the proper support you can get pretty close to center very easily. I’m happy with it and the new bit drill straight also.

The last 2 section require so special links to get clearance for the the cylinder shaft as they have to go past 180 degrees.
To make them I drew up templates and pinned and folded boom sections until they moved and gave me the clearance necessary. I traced them out on 1/8” plywood and cut around them on the scroll saw.

I then stacked them with double side tape and off to the belt sander to get them all the same shape and drilled holes and ready to install.

Tomorrow we’ll install those and be close to finish time.

-- Bruce, Boise, ID

2 comments so far

View Dutchy's profile


1976 posts in 1592 days

#1 posted 12-10-2015 05:35 PM

Nice lathe chuck and a drill chuc and of course the concrete pump.

-- My englisch is bad but how is your dutch?

View helluvawreck's profile


22707 posts in 2290 days

#2 posted 12-10-2015 05:47 PM

That’s a nice set of chucks and the project looks great and is very detailed. Congratulations.

helluvawreck aka Charles

-- If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. Henry David Thoreau

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