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Discussion Starter · #1 ·
An old friend in Florida is sending me a bar of bronze. 5-3/4" diameter by 13" long. He sent me this picture via email and wants me to turn it into a beer can mortar. The material is described as bearing bronze. So my question is what is this picture of and what scale would this be. I'll keep looking for a drawing but if anyone knows of one I would be grateful.

Also I have a lot of 1-1/2" Bronze round bar. Would that work for the trunnion bar or is it to small?

 

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This photo is showing a group of British Coehorn Mortars on a mortar cart in the Artillery Park just outside the sally port and sentry box of Fort Ligonier located south and east of Pittsburg, PA in Ligonier, PA at 200 South Market Street, Phone No.: 724-238-9701. Since you live reasonably close to them, I would visit and take measurements off the replicas. The owners of this Fort spared absolutely no expense in re-creating every detail of it at its height of use during Pontiac's War in 1763. They did impeccable research on each bronze artillery piece chosen for replication. The British Coehorn Mortars are full size and are adorned with correct cyphers for that French and Indian War Period. It's an amazing place to visit; we liked it so much we came back the very next year in 2013 after discovering it in 2012.

Good luck!

Tracy

Me at Ft. Ligonier with a 5,000 pound, bronze, 13 Inch British Mortar.

 

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Tracy, is that Trunnion about the same size as the powder chamber in diameter?
 

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Boomlover, the specs for the 13 Inch British Land Service Mortar are in this reference volume somewhere..... We have no interest in re-creating British bronze smoothbore mortars so we did not do any measuring of them while we were there.

Doc Brown, you can find measurements for the British Coehorn Mortar, 4.53 Inch and the British Royal Mortar, 5.5 Inch in this same reference as soon as you decide which one is depicted in your photo.


http://www.sha.org/assets/documents/British Smooth-Bore Artillery - English.pdf


Tracy
 

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Hi Doc I have a bronze Mortar less than 6' away from me that measures o/a l is 11 3/4" bore is 5 3/4" trunnions are 2" dia by 9" long. It has a tapered conical powder chamber. Looks like it would fit nice. I can send pix to any e-mail addy. Still cannot figure the GB pix thing ;-) John (exlimey)


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Send the pix to gunnyg @ commspeed.net and I will load them on my website and put them in your post.

OK, now edit your post and add appropriate captions.
 

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exlimey said:
Hi Doc I have a bronze Mortar less than 6' away from me that measures o/a l is 11 3/4" bore is 5 3/4" trunnions are 2" dia by 9" long. It has a tapered conical powder chamber. Looks like it would fit nice. I can send pix to any e-mail addy. Still cannot figure the GB pix thing ;-) John (exlimey) The top pic is the wood pattern the two bottom pix show the two wheeled carriage for what was termed a Hobit carriage, these were used at Ft Stanwix and also show up at Yorktown. First accounts show up in the 1730s, a period panoply of arms drawn by Johan Baumann shows the front 2/3rds of it and rest is my educated guess. These were probably used for Infantry support. My thanks to gunny for the pix !


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Discussion Starter · #8 ·
Thanks Tracy. I go to ligonier many many times a year and will make sure I stop there and see this place soon. British Cohorns look like they are much larger than the civil war Cohorns.

Exlimey jeez o wiz. That mortar is beautiful. What's the black stuff on it? Some kind of cosmoline for bronze?

Edit. I just seen you said that's a wood pattern.
 

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exlimey said:
exlimey I like the use as a "moritzer" first time I came across this use was at a re-enactment in New Jersey I always planned on building one with mine but never got around to it before I sold it.....
 

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Discussion Starter · #10 ·
Copied out of the stickies. "A popcan mortar with proper windage needs a bore of 2.667.
A Diet Coke can is 2.6 inches in diameter. (2.6/39)x40=2.667"



Well it's here. What a beautiful thing bronze is.

I'm still working out the design. Mainly the size of the powder chamber
 

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Doc, just a suggestion. You might want to change out the chip tray on your lathe and save all that bronze from your latest build. Stuff ain't cheap and could net you a few bucks on the side. From the swirls on that soon to be mortar stock looks to be bearing bronze and should generate a whole bunch of little chips. They still use it down here for bearings on cane carts (sugarcane) and some older tractors. And they tend to fly all over the place. Have fun. Frank
 

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Discussion Starter · #13 ·
Thanks DD. That spread sheet is what I'm going to go off of for the powder chamber. I'm glad you sent that to me. Thank you. It's going to have a much larger powder chamber than I thought but that's a good thing.
 

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Discussion Starter · #14 ·
I'm back and would love some opinions on a thing or two. Anything wrong with calling it quits on this mortar and leaving the material behind the trunnion hole? Or should I flip it around and bring the radius off the bottom back to around half the trunnion holes diameter?

If I stop here am I crazy?




 

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Doc said:
I'm back and would love some opinions on a thing or two. Anything wrong with calling it quits on this mortar and leaving the material behind the trunnion hole? Everything is wrong with this idea.[/color] Or should I flip it around and bring the radius off the bottom back to around half the trunnion holes diameter? Generally this is close to what you should do. Basically, follow the drawing or photo you have and make the entire shape authentically.[/color]

If I stop here am I crazy? YES.

Doc, you are a superlative craftsman! Obliterate that breech end hole thing, create the proper breech end angle, bolt the 1.5" bronze shaft on the Crescent shaped end receiver notch, build a couple gusset wedges, pin and epoxy them in place and your done.

Everyone, please remember, the smaller your re-creation, the more critical the observer's eye will be. Every detail should be as close to authentic as possible.

IMHO,

Tracy
[/color]



 

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Maybe you can get some of your chips reduced to fine pieces and use them for a filler in your epoxy.
 

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Discussion Starter · #19 ·
Should I be scared to chuck on the muzzle and run this in a steady rest. Who thinks I'll have the support to radius the back off that way? I'm sitting here thinking about this. Thank you.




Also, what the biggest vent hole I could go with on this beer can mortar. I don't want to use a small vent for fear of breaking it off in the vent. This stuff drills WEIRD. It seems to shrink around the drill bit.
 

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Standard over the counter cannon fuse diameter is 1/8". Yes you can get smaller. But generic is 1/8". Rule of thumb for vent diameter is is 1-1/2 calibers. 1-1/2 times 1/8" is 3/16" (.1875") This size works good for the 4mm artstraw quills.

Now there are those who say that is to big and there is to much pressure loss...while in practice the loss is insignificant in the guns we build.

On the other hand a vent that is too small in diameter is prone, misfire, excessive vent fouling and short fusing.

For Friction primers, I use a number 76 drill (.200") That is full cannon vent
 
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