Wall Thickness????? PIC UPDATE

[sgtgeo]

I'm new and confused

I keep hearing that the wall thickness needs to be 1 caliber

So for a golf ball size mortar the wall thickness needs to be ~1.7" minimum.  so the diameter of the mortar would be 5.1"

In all the pictures I've seen never have i seen a golf ball mortar that would meet that requirement


and what about the bowling ball mortars?  they would need to be 2' thick, yet usually they are made from gas cylinders.

I bought a mortar from a guy on ebay

specs:
5" tall
3.5" at the base
3" at the muzzle
3.8" bore to the top of the rounded powder pocket
4.1" to the lowest part of the powder pocket

it's made of 4140,  Is it safe to shoot golf  balls?

[Rickk]

With a mortar or a howitzer that has a sub-chamber, the wall thickness requirement is around the powder chamber. The pressure drops as it enters the major bore diamter, so the 1 wall thickness doesn't apply there.


Your "powder pocket"... what is the diameter, and is there that much wall thickness around it?

[Cat Whisperer]

Stggeo - WELCOME to the board!  Post some pictures when you get to it!

I agree with Rickk - that for golf balls it'll be OK (especially with 4140), but here's the consensus on wall thickness:

The area around where the powder is should be thick steel - as thick as is the diameter (one caliber) on each side AND behind it as well.  So if you have a small diameter powder chamber it takes only  a little steel around it.  After the peak pressure passes (time wise) the ball is then pushed out the tube with a huge volume of expanding gas - but at a lower pressure as the powder chamber is smaller than the bore inside diameter - hence a thinner wall thickness is adequate.  Other considerations are the metal used, the inside geometry (sharp or rounded inside corners) and of course how reasonably the cannon/mortar is loaded.

Golf-balls are very light and not as much pressure is built up behind them compared to any other metal used.

[sgtgeo]

Here are some pics,  Not my pics but this is it





Weighs 12+ lbs and is 4140

This is the guys trunnion model:

[Rickk]

Is there a powder chamber in it, what are it's dimensions, and what is the thickness around and also under the chamber?

Almost everyone that guy on ebay sells to winds up here. He needs to visit and figure out what he is doing so his customers know what they have.

[Cat Whisperer]

Thanks of the pix!

It looks Danish Modern (oops that's furniture).  I like the taper.  Fuse hole looks appropriately small.

With golf balls, I'd shoot it with 30-60 grains of FFg and NO wadding - should get you out there 100-200 yards.

ANYTHING heavier than a golf ball you NEED to look closely at the design.

The fuse hole looks (unless it's in at an angle) very close to the bottom - depending of course on the size of the powder chamber.  With golf balls AND a reasonable charge that's no worry, BUT on the edge for anything else.

[sgtgeo]

The fuse hole .125" enters at the bottom of the powder pocket.  There is not really a chamber more like a hemispherical depression.  There is a shoulder approx .25" then the depression which is not very deep maybe .25"

Here is a link to the auction

http://cgi.ebay.com/4140-HS-ALLOY-GOLF-BALL-BLACK-POWDER-CANNON-MORTAR_W0QQitemZ280124866346QQihZ018QQcategoryZ73979QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

It would be great if someone could contact him and ask the right questions

Well is has to be safer then the pipe with threaded end-cap  I was planning on using

[Double D]

Here's the description from Ebay posting:

MADE FROM 4140 ALLOY HIGH STRENGTH STEEL, SOLID STOCK. Its chromium content provides good hardness penetration, and the molybdenum imparts uniformity of hardness and high strength.  With a combination of such highly desirable properties as good strength and wear resistance, excellent toughness, coupled with good ductility, and the ability to resist stress at elevated temperatures.


SHE IS 5 INCHS TALL. 3-1/2 INCHS WIDE AT BASE, TAPPERS TO  3" INCHS WIDE AT THE BUSINESS END. THE BORE IS +-.060" UNDER 1-3/4 DIAMETER (PERFECT GOLF BALL ACCOMADATION) BY 4 INCHS DEEP WITH A TAPPERED POWDER POCKET. FUSE HOLE IS 1/8 INCH. WEIGHS OVER 12 POUNDS.

NOTICE: THIS IS HOW  FOR TESTING ONLY BUT REALLY PROJECTILE SHOOTING YOU CANT, I DO IT JUST TO VERIFY SCALE ACCURACY. BY REDUCING THE  BORE BY ONLY +-.060" THOUSANDS AND USING ONLY ABOUT 400 GRAINS FFG, I GET AND EXTRA 300 TO 400 FEET OF FLIGHT FOR A TOTAL OF 3,350 FEET OF GOLF BALL DISTANCE WITH THE MORTAR AT A 45 DEGREE ANGLE. (golf balls come in at 1.687" but need a bit of room for expansion and deformity) ACCORDING TO E-BAY RULES THIS ITEM IS NOT MADE FOR PROJECTILES.

I HAVE DESIGNED AND TESTED THIS CANNON-LIKE THUNDER BARREL TO JUST THE RIGHT COMBO OF LENGTH AND DIAMETER FOR MAXIMUM BOOM.

I  USE 1500 PLUS GRAINS OF BLACK POWDER IN THIS ROCKER. **************

NOTE: SORRY, BALLS, SODA AND FUSE NOT INCLUDED.

PLEASE CHECK MY NEW WEBSITE


Let's do the math.

5 inches tall, bore is 4 inches deep.  It seem to imply that includes powder pocket.  That leaves you with 1 inch back wall.

Side wall largest diameter 3.5 inches. That makes the side walls at the largest diameter  0.875. And this thing taper to 3 inch   The powder chamber is described as tapered but give no dimensions.

This thing doesn't not meet basic safety guidlines for construction and the recommended load is excessive.  Glad he used 4140 for steel.

You can do better than this thing for a golf ball mortar.





 

[GGaskill]

How about posting a picture shot straight down an empty bore?  That should give us some idea of what is going on.  But forget his load recommendations.  1500 grains of powder is absurd; even 150 is more than necessary.

Plus, if you launch any heavy projectiles, those trunnions seem undersized and inadequately attached.  Kind of looks like a thundermug with trunnions instead of a handle.

I took a look at the guy's website and do not have a good opinion of most of his products.  Most of them look like firecrackers waiting to explode as opposed to artillery pieces.  4140 aside, I am not impressed with his designs.

[Tropico]

My buddies Al .,Jeeper1 ., Santa Dave and my self watched a beer can of concrete go REAL HIGH and about 170 yards out on 150 gr 1FG. We cut it back to 120 FG and hit our target (a pond)  and still got 150 yards of flight ., with a high barely visible., but still visible flight ., which added to the enjoyment of the shot.  120 gr and beer can mortars are a good combo.   1500 is unrealistic ., that mortar must have been over flowing and brimming with powder...., his mortar runneth over. I am impressed with how little powder a mortar takes.   My buddy Dennis uses 100 gr in a .54 caliber lyman and on the same 100 gr I can fire a 2.68 caliber .., mortars are really great and fun on VERY LITTLE .

[jeeper1]

We really had a great time yesterday. That beer can mortar has a rather impressive voice. Oh yes, your and Al's swivel cannons really fired me up to get one. Maybe I can work a deal with Dominick for a twofer, a swivel cannon and a French 1897 both in golf ball caliber.

[dominick]

Maybe I can work a deal with Dominick for a twofer, a swivel cannon and a French 1897 both in golf ball caliber.

Hey jeeper, maybe you can!  Just let me know, I'm ready.  Dom

[Rickk]

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