Potato cannon carriage #2: Frame and elevating arc assembly and trunnion construction

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Blog entry by JJohnston posted 08-02-2010 02:07 AM 5873 reads 0 times favorited 3 comments Add to Favorites Watch
« Part 1: Frame/axle and elevating arcs Part 2 of Potato cannon carriage series Part 3: Trail, ramrod and major assembly »

This weekend consisted mainly of painting, painting, painting, some more painting, and after that, some painting. I’m using canned spray paint from the big box store, and the wood just soaks it up. It takes a good 3 coats before I can scuff sand paint without also sanding wood.

Here’s the frame with the elevating arcs attached to the sides, and the axle going through. It’s a 5/8” threaded rod, 24” long. The box stuck to the side of the left arc is to hold a breech plug wrench, which you’ll see later.

Here’s another angle. The paint color I settled on is Rustoleum “satin oregano”.

The trunnion assembly starts out as a double thickness of 3/4” baltic birch ply, just wide enough to fit between the elevating arcs without rubbing. I used a router with a circle jig to make 2 – 5” circles.

Then each piece is cut from its end of the blank and notched for the horizontal member, a 3/4” x 2 1/2” x 14 1/2” piece of baltic birch ply.

I drilled each piece vertically between the hole and the edge for lag screws, then split each ring horizontally through the center of the circle. Here’s a shot of the completed assembly, with the axle going through. It’s a 3/4” threaded rod, which will be cut to length later.

The rings clamp down on the cannon to hold it tight. The cannon is still painted in the green I chose initially, which I decided is too dark and too blue – more like the color of blue spruce. The lighter color is more of a sage green, and is a better match for my area.

Here’s a shot showing the relationship between arcs and trunnion. You can actually see through the slot, where the hanger stud will stick out of the trunnion assembly and will have a knob that will be tightened against the arc. The cannon is just propped up for this shot.

Next installment: trail assembly and ramrod.

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

3 comments so far

View lew's profile


12100 posts in 3778 days

#1 posted 08-02-2010 02:13 AM

This is gonna be so cool!

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View 559dustdesigns's profile


633 posts in 3190 days

#2 posted 08-02-2010 09:17 AM

Those bushes behind your place are in for a big surprise, soon. Thanks for the progress report.

-- Aaron - central California "If you haven't got the time to do it right, when will you find the time to do it over?"

View Dennisgrosen's profile


10880 posts in 3138 days

#3 posted 08-03-2010 12:01 AM

very niice progress :-)

have you seen Mathias homepage where he play around with some potatocanon

its not on hes woodsite but on the other site he has but there is a link on it


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