My British Militaria project-bowling ball Mortar

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My British Militaria project-bowling ball Mortar

The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

March 2nd, 2016, 5:12 pm #1

In the past few years my life has been a bit tumultuous to say the least.  I have not been doing much shooting  or working on gun building projects.  I have managed to get to a couple of the Victorian Rifleman shoots and get out gopher hunting in the spring.  The biggest distractions have been a trip I took to Afghanistan and chasing a wild woman from Oklahoma.  Let me tell you, your mind gets just as all messed up at 68 as it did at 16 chasing "wimmen". Well she caught me and we have been married a year and half now. Life is becoming more settled.

Even though I was distracted I do have British Militaria gun project of sorts I have been working on. I have been planning this project for about 10 years. Off  and on over the years i have been working on it. I got  it in my mind to build the Boer Mortar called Seeppot.     Seeppot was  a British 8 inch siege mortar on a traveling carriage.



Here is the 6 inch version



I did a lot of research on Seeppot and learned after the  Anglo-Boer it was it was taken to Manchester, UK as a war trophy. From there it disappeared-my guess in the scrap drives of WWI or WWII.
 
I looked around and found drawings of the mortar on a traveling carriage from the Royal Artillery Museum in Woolich. Such a carriage would solve issues on moving and transporting a large mortar especially for me.  Finding a crew is a bit tough in Montana. 



Here is a link to the drawing full size, just click on it.

http://www.fototime.com/B07CBD025E3BA85/orig.jpg


I had a number of problems to deal with in order to build this mortar.  First, how to build it.  It would be expensive to buy a casting and finish it.  If I could afford a casting then I could also afford to just buy a finished mortar, and where would the fun be in that.

I could also buy a solid round piece of steel and machine it myself.  I have the skills to do the work.  I do not have the machinery to work an 780  pound piece of steel, 12 inches in diameter and 24 inches long. The steel was still costly new, but surplus yards do come up with salvage pieces called shorts, left over from some other project.   The machining would have to be subcontracted and would take time and money.  It just did not seem feasible for me to do this project.

At a model cannon  shoot in 2009 I discussed  this project with other hobbyist.   The idea was put forth to use seamless steel tubing for the  barrel.  One of the gentlemen said he know of a scrap yard that might even have what I need.

A few weeks after the gathering I got an email from this gentlemen, saying he found my barrel steel.  That was great. Better even was he got it for scrap steel price.  With the help of Southpaw--Ernie, the steel was transported from Southern California to Montana. With the barrel came a piece of steel for the trunnion.   

Later during a trip to Pennsylvania for the first IMA shoot I acquired a piece of 4140 ordnance steel for a breech plug.  It was my intention to build the barrel in a pattern that had used to build several small golf ball and popcan mortar.  I called the  pattern the K.I.S.S. pattern.  It was designed to be a simple machining project; simple turning simple boring operations, no welding, bolt together.   The barrel is a piece of seamless tubing and is bored out projectile diameter part way down the barrel.  The breech plug is turned two diameters ans slip fits down the  barrel.  The  breech plug has a chamber drilled in it and is bolted in place by the trunnion.

Here is a drawing of  K.I.S.S. golf ball mortar. 



 Here is the accumulation of steel for the project as wel as a couple of the golf ball mortars.  The golf ball mortars were made to resemble the 24 PDR Confederate pattern Coehorn.



With the steel in hand I needed wood for the carriage.  I was lucky and found that right here in Montana. I had to buy the full beams. These are kiln dried fir.  I could not located a suitable hard wood.




I do not have a lathe big enough to hold the steel.  I found one of the local farmers had a lathe big enough and he was willing to  do the machine work for me.  I was getting ready to head off for Afghanistan and was going to drop off the steel and pick it up when I got back.  A week after I dropped the steel off he called back and said the barrel was ready.






One of the goals I set for this mortar was to shoot a bowling ball one mile.   With my departure to Afghanistan delayed, I just had to test fire this barrel  With the help of Ernie Taft- "Southpaw", I test fired the barrel.



This is as far as I got before leaving for overseas.
Last edited by The Double D on May 22nd, 2016, 2:12 am, edited 14 times in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

March 2nd, 2016, 5:27 pm #2

During the winter of 2014-2015 after getting home from Afghanistan, I took the wood with me to Oklahoma and worked on building the carriage.

I had a "large" obstacle to overcome.  I do not have much in the way of wood working tools, and especially nothing to work large pieces of wood. I have hand held tools.  And even those tools were all in Montana, 1500 miles from Oklahoma.  If I needed a tool in Oklahoma,  I had to go buy it. An even bigger issue is I lack woodworking skill.

First purchase was a drill press.  Once I had that I drilled three 1 inch cross holes to bolt the two 12" x 8" beams together .





I had to make brackets to mount the axle and then inlet wood base to accept the axle.



The base also had to be inletted to accept the trail or as the  British called it, the perch.





That is as far as I got that winter.



Summer 2015 I brought the wood back to Montana and worked on the top angle and trunnion relief.



That hole has a diameter of 4 5/8".

Next was cutting the slope top. This was a big job. A combination of circular saw, reciprocating saw and electric plane got it done.



This where I was at the end of summer 2015.

Last edited by The Double D on May 20th, 2016, 4:22 pm, edited 10 times in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

March 2nd, 2016, 6:55 pm #3

Winter 2015-2016 was devoted to working on the carriage hardware and the quoin. The quoin is the big piece of wood that supports the barrel.

I had to drill the quoin and cut the bottom to copy the base top angle. I also had to drill the holes for the quoin bolts in the base. The base and quoin bolts are 1" x 22" carriage bolts.



To make the cap squares and trunnion plates I had flat straps welded to a couple of rings I made on my lathe. The trunnion plate is what the trunnion on the mortar tube sits on, on the base. The cap square goes over the top of the trunnion and holds the barrel in place. To make this piece of hardware, I had the straps welded to the ring, I drilled two 1" holes on either side of the ring. Each hole had go through the cap square flat and then on down through the trunnion plate flat.These holes are for the cap square bolts.  Later I will up grade these bolt to Key bolts.  

 I also had to drill a 1-1/4" hole in the trunnion plate strap for clearance for the Quoin bolts.

Each trunnion plate flat also drilled for lag bolts to attach the trunnion plate to the base. When finished I had to drill 40 of these holes.



In the pictures above the trunnion ring still has not been cut to separate the cap square from the  trunnion plate.

In order to cut the ring and create capsquares and trunnion plates I needed access to a  vertical metal cutting bandsaw. We had to make a guick trip back to my house in Montana and while traveling from Oklahoma to  Montana, I stopped in Idaho and used my friends saw to make the cuts.



When we got back from the trip to Montana, I did the relief inlet for the  barrel.



This is where I was when it was time to go back north to Montana.

Last edited by The Double D on May 20th, 2016, 3:24 pm, edited 7 times in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

March 13th, 2016, 1:15 pm #4

Ernie has laid in a good supply of ammo for his bowling ball mortar.



I am going too use factory ammo. Factory new and unfired, no holes drilled, 4 to a box bowling balls.



Yes  Charlie, it is true as some say, I have balls!
Last edited by The Double D on May 20th, 2016, 3:38 pm, edited 5 times in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

May 5th, 2016, 6:06 pm #5

My goal for this mortar as Imay have said was to shoot a bowling ball one mile.   Fortunately living in Montana,I can fnd the open space to shoot that far. 

Here is one location for the possible one mile attempt.



This is the view to the impact zone from firing point 1. Arrow indicating impact zone.



This is from Impact zone back FP1. The distance is 1.21 miles on the GPS.



As you can see from about 1/4 mile to 1/2 miles in front of the firing point the ground drops below line of sight.  I am not concerned about someone drifting in there while we are firing as we can see and control all access to that ground.  What we can't see is the actual impact of the ball if it dropped in that zone.  Basic safety says you need to see where the ball hits.  We also need to see the impact for adjusting charges.

This is the view from Firing point 2 to the impact zone.



This is the view back from impact zone to FP2.  The distance on the GPS is 1.15 miles.



Again the issue of hidden ground.  

I have two other sites to survey.
Last edited by The Double D on May 20th, 2016, 3:47 pm, edited 1 time in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

May 15th, 2016, 4:22 am #6

Upon returning to Montana for the summer a high priority for me was to marry the barrel to the carriage.  Here is the barrel ready to be assembled and mounted.



Using the carriage to mount the barrel is pretty clever.

Move the  carriage to the  barrel.



Tip the carriage onto the trunnion and attach capsquares.



Tip the carriage back onto its end then back on its wheels.



Last, tip the carriage down into to traveling position.



To put the gun on the ground to fire, lift the gun up on its nose, remove the wheels and lower to the ground.

So this is where I am in this project. There is still finish and trim work to do-lunette, lifting handles, bolt trimming, edge rounding and of course painting.

Last edited by The Double D on May 20th, 2016, 4:06 pm, edited 1 time in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

May 20th, 2016, 4:24 pm #7

Now if you think I would put this all together and roll it out just for a glamour shot and not shoot it....

Make it full size.


6 oz Fa black powder, 12 lb bowling ball, 445 yards.

A detailed narrative of 18 pages describing this build can be found at K.I.S.S. Bowling Ball  Mortar
Last edited by The Double D on May 20th, 2016, 4:28 pm, edited 1 time in total.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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Pukka Bundook
Veteran of the Regiment
Pukka Bundook
Veteran of the Regiment
Joined: March 3rd, 2004, 3:19 pm

May 22nd, 2016, 2:40 am #8

I am Really impressed Douglas!

Lovely build, And it works!
You have done a fantastic job, and look forward to seeing it finished.

Yes, my cap is off to you. A Grand job!
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PommyB
Veteran of the Regiment
PommyB
Veteran of the Regiment
Joined: September 3rd, 2009, 9:41 pm

May 22nd, 2016, 4:22 am #9

We'll take it out after some gophers next week, Douglas, they'd better be wearing hard hats!
"For a man, be he ever so much resolved to do his duty as a parent, can't be flogging his children all day....."

The Memoirs of Barry Lyndon, Esq. (William Thackeray).
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Duncaninfrance.britishmilitariaforums
Veteran of the Regiment
Joined: February 22nd, 2008, 9:04 pm

May 22nd, 2016, 8:16 am #10

A brilliant and informative narrative Douglas, can't wait to see the 'finished' item 
[size=120]“Those who live by the sword are usually shot by those of us who don’t”[/size]

Peace is that brief, quiet moment in history.......... when everybody stands around reloading.
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Japlmg
Lance Sergeant
Japlmg
Lance Sergeant
Joined: January 19th, 2004, 12:18 am

May 28th, 2016, 7:21 pm #11

I friend of mine built a bowling ball mortar about 25 years ago.
It is a section of heavy wall stainless steel pipe with a screwed in and pined in place base plug.
He lives in Satellite Beach, Florida and has been building an artificial reef about a mile off shore, one shot at a time, ever since.
He cranks it up about four times a year on holidays, and he will have it blasting away this Monday for Memorial Day.

Gregg
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

June 11th, 2016, 5:45 am #12

This thing has a cool factor about it.!



Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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PommyB
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PommyB
Veteran of the Regiment
Joined: September 3rd, 2009, 9:41 pm

June 11th, 2016, 9:14 am #13

You going to tow it back to Oklahoma like that?
"For a man, be he ever so much resolved to do his duty as a parent, can't be flogging his children all day....."

The Memoirs of Barry Lyndon, Esq. (William Thackeray).
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

June 11th, 2016, 3:30 pm #14

PommyB wrote:
You going to tow it back to Oklahoma like that?
Third axle means I have to follow truck speed limits.  55MPH.  It will take us for ever to get there. 
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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PommyB
Veteran of the Regiment
PommyB
Veteran of the Regiment
Joined: September 3rd, 2009, 9:41 pm

June 11th, 2016, 4:18 pm #15

Ah, but I'd doubt if you'd have too many tailgaters!
"For a man, be he ever so much resolved to do his duty as a parent, can't be flogging his children all day....."

The Memoirs of Barry Lyndon, Esq. (William Thackeray).
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snider volley
Veteran of the Regiment
snider volley
Veteran of the Regiment
Joined: July 18th, 2007, 2:48 pm

June 13th, 2016, 3:15 pm #16

awesome work that is so cool and what fun to start zeroing in on a distant target
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The Double D
Veteran of the Regiment
The Double D
Veteran of the Regiment
Joined: March 11th, 2003, 5:45 am

June 12th, 2018, 1:44 pm #17

Well the test is nearly upon on us.  Thursday absent a visit from  Murphy, we are going t attempt the mile shot.  Anyone in the area of  Cut Bank, Mt is welcomed to watch.  I need spotters.  Bring Binoculars and your ATV.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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PommyB
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PommyB
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Joined: September 3rd, 2009, 9:41 pm

June 12th, 2018, 8:07 pm #18

What direction will you be firing it, Douglas?  With a good tail wind there's a possibility I may see the ball arching over Spokane! 😱
"For a man, be he ever so much resolved to do his duty as a parent, can't be flogging his children all day....."

The Memoirs of Barry Lyndon, Esq. (William Thackeray).
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The Double D
Veteran of the Regiment
The Double D
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Joined: March 11th, 2003, 5:45 am

June 14th, 2018, 1:04 pm #19

Martyn, I will firing south and the wind is supposed to out the WSW so Spokane is safe. 

I wonder how much drift there is from 25 mph crosswind for a 15 lb bowling ball going 300 fps MV at 45 degrees.
Douglas

"And don't forget.  That isn't your Martini you have.  It  belonged to others before you and will belong to others after you are gone.  Look after it, and pass it on with pride. It deserves it."  Malcolm Cobb,  The Martini Henry Note-book
*********
To find things Martini go to: WWW.MartiniHenry.com
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CQMS
Sergeant Major
CQMS
Sergeant Major
Joined: September 9th, 2017, 8:49 pm

June 15th, 2018, 6:41 am #20

That just has to be the coolest thing I have ever seen. Wish I could be there for the main event!

CQMS
Being first isn't everything. Remember, its the second mouse that gets the cheese!
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