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Author Topic: Gribeauval Mortar base input  (Read 1925 times)

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Offline accuratemike

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Gribeauval Mortar base input
« on: July 12, 2006, 02:05:43 PM »
THANKS MATT ! I'm glad to see GBO back.

I'm a little confused about the configuration of the base for my mortar.
Looking at the drawing George posted, I think that Cannon-Mania's 1" "Yorktown" has the metals & woods mixed up on their base.
I cropped this from a pic posted on GBO:



And this from the drawing:



I colored in the drawing. Gray & Black would be Iron, Brown is Wood and the Barrel in Bronze. I do believe the brass caps on the CM are 180° out (If they are to replicate the Iron cheeks as described in the drawing)
 My plan is to use a chunk of 3/8" steel for the base (6.25"x8.875") with notches to accept 1/8" steel cheek plates that I will weld in. I made a CNC torch table once, and I would use it to cut out the pieces. Below are images of the CNC files in a simulator window:





(The torch has a .050" kerf, so the drawings are of the cut lines rather than the outline((a little smaller))
These, along with wood cheeks and cross pieces would make up my base. I was going to inlet the cheek plates into the wood, so the sides would be flush. I plan on using 2" stock for the sides, routed and thinned to 1 1/2" at the trunions. Cross pieces at 2 1/4" would give me the overall width of 6 1/4"
Any thoughts ?  Any input will be greatly appreciated. Thanks, MIKE
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Offline GGaskill

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Re: Gribeauval Mortar base input
« Reply #1 on: July 12, 2006, 02:55:42 PM »
My opinion from looking at the Round Shot and Rammers drawing is that the whole cheeks were probably cast iron and the wood was the cross pieces between the cheeks (which fit in depressions on the insides of the cheeks).  The brass on the Cannon-Mania one is strictly decoration.  There are cross sections of the cheeks above the side elevation of the mount and the interior depressions are obvious there as well as the reductions in thickness before and behind the trunnion area.

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Offline Powder keg

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Re: Gribeauval Mortar base input
« Reply #2 on: July 12, 2006, 03:14:30 PM »
I agree with George. The only thing I might add is that the cheeks are fatter near the bottom (ground) and skinnyer near the top where the trunnions sit. Did you get your trunnions attached yet?

Wes
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Wesley P.
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Offline accuratemike

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Re: Gribeauval Mortar base input
« Reply #3 on: July 12, 2006, 03:46:37 PM »
The trunions are on. TIG welded. They stick-out 1 1/2" and are 1 3/8" dia. I saw the cross sections.
Pics are at the bottom of this link
http://www.graybeardoutdoors.com/smf/index.php/topic,88832.0.html
The cross sections and the top view don't exactly sync. You have to use a little artistic license. I thought vertical sides wouldn't be to far off the mark. Sure would be easier. I thought if I used a little steel, it would look keen. If the sides were as we assumed, the cheeks would have angled bottoms and the cross pockets would be angled likewise..
I could easily angle the sides, if I could convert the side view into some kind of .dxf to cut the plates. I don't do 3d and to convert the plan view to some angle is tough. I would still use wood for the bulk of it. I wouldn't want to mill off 3 1/2" x 8 1/2" of steel to some angle (twice).  I can saw wood. Maybe wood sides with steel plate on the outsides.
Still just thinking either way. I could burn it out tonight the way it is in the pics above....
Thanks, MIKE
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Offline Powder keg

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Re: Gribeauval Mortar base input
« Reply #4 on: July 12, 2006, 04:59:49 PM »
A good hard wood would probably be easer? Sand it good and put a few coats of paint on it. No one will know. Just my two cents, Wes
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Wesley P.
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Offline accuratemike

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Re: Gribeauval Mortar base input
« Reply #5 on: July 12, 2006, 05:12:29 PM »
I've been thinking metal. I have a powder coater & oven too. The cast iron gray looks pretty dern good. I'd like to use the fun tools some too. It doesn't really matter anyhow. As long as she's pretty close. (and just plain pretty) I'll keep you posted. MIKE
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Offline GGaskill

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Re: Gribeauval Mortar base input
« Reply #6 on: July 12, 2006, 08:34:51 PM »
I'm thinking aluminum; plenty strong, easily machined and cast, if that is desired, and light weight.

The cross sections and the top view don't exactly sync.

That's certainly true.  The plan view shows none of the detail that the elevation does.  Simply a flat slab side with a trapezoidal cross section.  Maybe there were multiple versions.  You pays your money and takes your choices.
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Offline Double D

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Re: Gribeauval Mortar base input
« Reply #7 on: July 13, 2006, 04:59:56 AM »
That base is solid cast Iron.  I would get some heavy steel plate and cut the cheeks out and them mill the reliefs to maake it look the original. You you can do as much or as littled detail as you like.   Then I would use a course sand and sand blast to cheeks to give it that cast iron look.

The steel cheeks and the barrel will give the gun that solid mortar feel and help with stabilze it for shooting.



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Offline accuratemike

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Re: Gribeauval Mortar base input
« Reply #8 on: July 14, 2006, 02:38:17 PM »
Hmmm....Cast Aluminum. Another bunch of fun tools I haven't fired up lately.  :) MIKE
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Offline GGaskill

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Re: Gribeauval Mortar base input
« Reply #9 on: July 14, 2006, 02:42:17 PM »
Hmmm....Cast Aluminum.

A lot more work but ... Go for it.   ;D
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Offline GGaskill

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Re: Gribeauval Mortar base input
« Reply #10 on: April 18, 2007, 09:44:01 PM »
So did you go with the cast aluminum cheeks?
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Offline accuratemike

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Re: Gribeauval Mortar base input
« Reply #11 on: April 22, 2007, 12:39:55 PM »
Sorry,
My computer shows me mostly blue screens and safe mode right now. I had to finally navigate myself here via the kid's computer. No, I have not built the base yet. I never should have done the temporary base. It is like putting a couch, fridge and TV in the partially finished basement. Once I could shoot it, the project slowed way down. If/when I do, I think I'll go flat sided. The stuff above pretty much sums it up, and alot of the work is done. I have the steel and wood to do it that way too. You never know. When the mood strikes me I am prone to do just about anything. MIKE
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