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Discussion Starter · #101 ·
I have the sides put back together. Getting the 5 plates /spacers of each side aligned for the 29 bolts was a bit of a challenge.

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Our weather for the next few days looks favorable for more outdoor painting.
 

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Just a fine point on your carriage, traditionally the nuts go on the outside. Check out the photo of the 13in dictator mortar on line. Or this 8in mortar on youtube.
 

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Discussion Starter · #103 ·
Thanks Moose. I’m kinda stuck. The outside plates of each side are square punched holes for the carriage bolts. The side plates are close to identical but not interchangeable - at least not without some effort.

I’d seen a few examples of the bolt head on the outside and I liked the look, and am pretty committed to it now.

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It is entirely what you like, My point was made in case you weren't aware of it . After all I wanted modern rubber artillery tires on my 40mm so I could tow it. 😁
 

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Discussion Starter · #105 · (Edited)
Moose… I’ve come to realize I’m a rookie mortar bed builder!! I should have sought more input from the full forum from the start. At this point, not historically correct, but the best I could do.

Hoping it does not do back flips when Double D fires it off :oops:
 

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Discussion Starter · #106 ·
More progress with prime and paint.
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The sides are assembled. Hoping the prevailing locknuts work as expected.

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The inside of each side and cap squares finally have their first coat of paint on them.
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Discussion Starter · #107 · (Edited)
Now we’re starting to look like something.

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Hoping this is the final coat of paint. If it is, once the paint has cured, next is getting the mortar on the bed.
 

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Discussion Starter · #109 · (Edited)
I picked up the GOW mortar from Double D on July 11th last year. It took me until December to get to work building the bed and now 7 months later the project is pretty much complete.
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Brilliant! That turned out so nicely. Looking forward to the firing. BZ!
 

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Discussion Starter · #111 ·
Thank you sir! Navy guy? I’m not, but worked at FDX for a long time and Fred Smith carried Bravo Zulu to the corp culture. Received a number of them over 21 years but yours is most special. T
 

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Discussion Starter · #112 ·
Prior to assembly we weighed all of the parts of the bed - final tally: 448 pounds. Double D told me the GOW mortar is 458 pounds. Very beefy combo.
 

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Trey,

That carriage came out beautifully. Nice work.


What is supporting the barrel to keep it from moving when fired? It appears to be hanging there by friction alone. There are some very strong force at play when these guns fire.

 

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Discussion Starter · #114 ·
Great video Douglas. Looking at the video you posted on your Double D Legacy post your mortar does not flip back like it does in the video above. Was the your mortar bed modified between the 2 videos?

As noted, I'm new to all this! Friction is what is holding mine in place. I've seen mortars with the elevation screw - most notably the seacoast mortars - that support the muzzle but have not seen anything that would prevent a mortar from flipping back.
 

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Simple matter to lock the barrel in place with brass shims and tighten cap squares if it flops back . You did a good job in finishing , now to move it out to the firing line . At about 900 lb no small feat.
 

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Yes, the flip back is bounce, it recoils down first and bounce up Her is the rub mark on the bottom of the barrel and corresponding mark on the quoin.

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That wood is compressed. Notice the shape of the mark on the barrel is the same as the compressed wood.

I stopped the flip by putting rosin on the trunnions and tightening down the cap squares-tight. Also I didn't "see" flip or bounce until I got into heavier charges. But recoil forces are still present with light charges. Moose's idea about brass shims is good also. My Cairo cannon has shims.

One thing I have observed is after firing this mortar is the ground under the mortar has a definite imprint of the base showing downward and rear ward movement--recoil. With a 15 lb ball and 6 oz of powder, recoil velocity is a bit over 7 feet per second. Energy is about 614 ft lbf. After firing that 6 oz load in the legacy vide, it was very clear looking at the ground you could see the marking where the gun slide back.
 

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Discussion Starter · #117 ·
Thanks Moose, and Douglas. Initial firing will be with a light charge, hoping it does not end pointing up, or backwards, and then close inspection of the trunnion plates / cap squares to make sure everything has held together. And then slowly stepping up to heavier charges. Provided the results of firing blank charges goes well, the true test will be live fire one day down the road.
 

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... the results of firing blank charges ...

My experience with "blank" charges in bowling ball mortars has been singularly unimpressive. You need significant resistance from something to get a boom instead of a whoosh.
 

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That shooting stand really adds to the spectacular job you did on his mortar! Really looking forward to seeing the firing.
 
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