Author Topic: Bowling ball Mortar pwder chamber dimensions and loads (Read 2411 times)

Double D · « **on:** March 14, 2009, 04:13:28 PM »

Gent swith bowling ball mortars, what are the dimension of the powder chambers of your mortar and what charge weigths do you use?

NitroSteel · « **Reply #1 on:** March 14, 2009, 04:53:58 PM »

My powder chamber is 2 inches in diameter and is 2.5 inches deep. I typically use 3 ounces of BP and get about 500 yards of range... Have used more, but tend to lose "ammo" in the woods when I do.

1Southpaw · « **Reply #2 on:** March 14, 2009, 06:06:35 PM »

Chamber walls ? 2" inside diameter ? outside . ??

Buiding a BB motar , have the tube and end plate , wondering about the powder chamber .
Want a mortar not a bomb ....

BoomLover · « **Reply #3 on:** March 14, 2009, 07:36:16 PM »

There are a couple of Bowling Ball Mortar or Cannon makers in this GBO forum, one of them could probably tell a person correct info so as not to manufacture a "mistake waiting to happen"! I agree, best to do it right the first time than to learn from a mis-hap! We don't need or want the adverse publicity! BoomLover

dominick · « **Reply #4 on:** March 15, 2009, 02:43:14 AM »

I think I made this one 1.75" x 2.5" deep. I'm not sure, I'll have to check.

Double D · « **Reply #5 on:** March 15, 2009, 04:25:08 AM »

Well Dom's mortar chamber would be 5.25" OD minimum x 4.25" long minimum. Nitrosteel's would be 6" x 4.5" OD.

Anybody else have a bowling bal mortar and can give us dimensions?

NitroSteel · « **Reply #6 on:** March 15, 2009, 07:07:43 AM »

I believe you are correct on mine DoubleD. Very similar to the "Florida Bowling Ball Mortar":

http://www.gboreloaded.com/forums/index.php/topic,28013.0.html

SLEEPY BEEPER · « **Reply #7 on:** March 15, 2009, 06:29:38 PM »

My chamber is 1.375 inch dia. and 3.8 inches deep. Wall thickness at the breech is over 2 inchs. This is for safty and to add wieght to the barrel. Filling it up will send a ball over a 1/4 mile. I've never measured it. Now days I shoot for accurecy. Bowling balls roll badly when being shot at ranges under 150 yards. So I shoot at 65 Deg. out to 150 yards. And 45 Deg. over 150 yards. One ounce of powder will send a bowling ball 135 yards at 65 Deg. And 180 yards at 45 deg. If you will be shooting for accuracy you should plan on getting you mortar to at least 100 pounds or more (heavy breach and strong base). Other wise it moves around to much. I have had over 50 bowling balls. And the difference between the biggest and smallest was .220 inch in dia. And lastly. Balls will change size when sitting in the sun. A ball that fits at home. May stick after sitting in the sun all day. Ask me how I know.

1Southpaw · « **Reply #8 on:** March 16, 2009, 03:37:49 AM »

Thank You
Dominic : that looks right nice .
Sleepy Beeper : thank you for dimentions and load info.

The picture of the material on the saw is going to be my powder chamber . It is slightly over 5 " diameter . After consutation with Douglas I'm thinking a chunk 6" long will do the trick. Going for a 1.5" chamber and 3.5" deep . My pipe is 9" ID and .354 wall thickness . Not seamless but it is new pipe.

Cannoneer · « **Reply #9 on:** March 16, 2009, 05:39:41 AM »

Quote from: SLEEPY BEEPER on March 15, 2009, 06:29:38 PM

Ask me how I know.

How do you know?

SLEEPY BEEPER · « **Reply #10 on:** March 16, 2009, 10:47:26 AM »

Several years ago at my first mortar / cannon shoot. I was ready to clean house with my new bowling ball mortar. I had been practicing. I showed up early to set the mortar and thru my black bowling balls in the sun. Ate lunch and watched the cannons shoot. Two in the afternoon the mortar shoot started. It was hot. The balls where almost to hot to handle (like a hot car hood). 4 of my 10 balls would not even start. Left with my tail down. On another occasion I was shooting a light load (100 yards). I forced down a hot oversized ball (many moons ago). On firing it went over the target field, over the trees and kept going. Never did find the ball. It had to have stuck. Builting up excessive pressure until it let loose. I have read where people believe all the pressure is in the breach. The barrel just guides the ball. In a perfect world maybe. Now days I plan for worst case.

Cat Whisperer · « **Reply #11 on:** March 16, 2009, 02:31:01 PM »

Quote from: SLEEPY BEEPER on March 16, 2009, 10:47:26 AM

....
Now days I plan for worst case.

Great philosophy of life - for surviving!

1Southpaw · « **Reply #12 on:** March 16, 2009, 04:58:31 PM »

Mortar Chamber material . 6" length , 5 1/8" diameter . Chamber currently 3.375 deep and 1" Diameter . Am going to drill bore out to 1.5 " tomorrow .I do not have a boring bare for this old lathe .The dish is 25 degrees . Ball sits nicely on that angle . Measured 2 balls , both were 8 9/16" My tube measures 8 15/16" . Should work ok I hope.

More to come

Double D · « **Reply #13 on:** March 16, 2009, 06:23:28 PM »

Is that all the further you got? I'm head your way tomorrow withpowder fuse and another mortar ball.

Maybe I should dig my boring bar out.

Cannoneer · « **Reply #14 on:** March 16, 2009, 08:48:08 PM »

Quote from: SLEEPY BEEPER on March 16, 2009, 10:47:26 AM

I forced down a hot oversized ball (many moons ago). On firing it went over the target field, over the trees and kept going. Never did find the ball. It had to have stuck. Builting up excessive pressure until it let loose. I have read where people believe all the pressure is in the breach. The barrel just guides the ball. In a perfect world maybe. Now days I plan for worst case.

Thanks for the answer, Sleepy Beeper; By what you describe, things could get dangerously complicated by all that added distance given to the ball by the increased pressure caused by the tight fit.

Cat Whisperer · « **Reply #15 on:** March 17, 2009, 12:33:05 AM »

Quote from: 1Southpaw on March 16, 2009, 04:58:31 PM

...
I do not have a boring bare for this old lathe.
...

I 'bored' my first mortar without a boring bar. I used a 3/4" bit clamped in the tool holder - it's all I had. Beer-can caliber too.

Max Caliber · « **Reply #16 on:** March 17, 2009, 01:29:42 AM »

If one is handy at grinding lathe bits, a very servicable boring bar may be made from large, inexpensive masonry bits. You will need a carbide tool grinding wheel to shape the tip though.

Victor3 · « **Reply #17 on:** March 17, 2009, 02:55:45 AM »

Quote from: 1Southpaw on March 16, 2009, 04:58:31 PM

I hope you're taking very light cuts, considering the 'fingernail hold' the jaws have on that heavy, unsupported workpiece...

1Southpaw · « **Reply #18 on:** March 17, 2009, 07:18:46 AM »

is the rule with this old lathe , flat belt drive slips $:-\$
The 4 jaw chuck has a very good hold on that piece . The jaws are reversed and do have serations on them. It's been years since I last used this lathe . I bough it 30 years ago @ an Auction for $125 . No chuck or tooling with . I bought the 4 jaw so I could chuck up odd pieces .

KABAR2 · « **Reply #19 on:** March 17, 2009, 08:43:05 AM »

Even with serations that object is not being held by much, I would not get my body in front

of it while turning! people have been maimed or killed by chunks of metal trown out of the chuck, by the looks

of your cuts, it looks like your removing small amounts of stock with each pass which is good, no critisim here just

want people to stay safe.

1Southpaw · « **Reply #20 on:** March 17, 2009, 06:55:03 PM »

I hate it when that happens . Guess I need to type my posts up in note page then cut and paste.

Yep ,light cuts and so slow if it felll out of the chuck it would fall on my toe ..... and that is not going to happen , besides , I'm a dumb farmer and every one know the Good Lord looks out for fools

Well Douglas blew in today . Litterally he did . Said it took .5 gallons of gas to get here , Had a full tank when he left , hoped the other 20 gallons would get him west in to the wind . As a precaution he ate all the Cholate Chip cookies in case Katherine had to walk for gas .

He brought over his boring bar , it didn't fit my 60+ year old South Bend lathe. So he ate the cookies and left . Left me wondering how to get the 1" hole out to 1.5 " or a little better ...

Soon as Doug left , "Good Neighbor Don" happen'd along . He is a BIG good natured fellow who can break a ball bearing just by looking @ it . He has been by every day since I started this project . All he wants to do is "Help " . His attention span is even shorted than mine ....( bet you didn't think that was possible ? )
Any way .... I mentiond that Dougs boring bar didn't fit on my lathe , also mentions that one of you fine fellows said they made a boring bar out of a carbide bit .
No sooner did I mention that when Don is in to my "bit drawer" looking .... I quickly picked out an old well used masonary 3/4"bit . He said , : "That will work " and before I could say ," Well lets have a look see "
He was @ the grinder grinding down the 1/2" round shaft to make it fit in the tool holder on the lathe.
Well it didn't cut , so.... we wear out the rest of the grinding wheel to make it look like it would work .
didn't work but it sure true'd up the grinding wheel .
I had bought some diamond grinding disc's for my dremel , so we shaped the Masonary bit a bit and gave it a go .... More to follow :>)

1Southpaw · « **Reply #21 on:** March 17, 2009, 07:10:16 PM »

boring bar @ work . Thanks for the idea .

finished hole ..

Doug brought over some fuse and Cannon grade powder ...
More to come ....

Double D · « **Reply #22 on:** March 18, 2009, 03:54:15 AM »

You guys should see the lathe South Paw is working with! It was old when Ernie was born!!! It is an Old South Bend table top school lathe. Still going strong...

Ernie only thinks I brought him powder and fuse...it was a ruse to get at his wife's choclate chip cookies.

seacoastartillery · « **Reply #23 on:** March 18, 2009, 06:03:17 AM »

1southpaw, The next time you see Double D's vehicle coming up your driveway, hide those cookies!! THAT will get his attention and then you can explain the finer points of the "Mature" South Bend lathe you use so well. Mike and I both have soft spots in our hearts for the old South Bend "School" lathes we used at the Colorado School of Trades in the mid 70s. Ours had 4 or 5 flat belt slightly crowned step pulleys to the left of the headstock which really dated them. Although they are all replaced by more modern equipment now, they were capable of good work, as we turned 7 different threads on one multi-diameter journal as a learning project and chambered and threaded more than a few high power rifles on them.

Looks like yours is working just fine. Nice photos too and your explanation of what we are looking at is top-notch and goes a long way in explaining to our non-machinist members what is going on. Thank you for posting this thread.

Regards,

Mike and Tracy

1Southpaw · « **Reply #24 on:** March 18, 2009, 09:40:06 AM »

seacoastartillery : Doug is a Cookie Monster !

Now wife is going to have to bake up another batch ...

Good deal as she doesn't like to bake cookies for me

This old South Bend Lathe came to the local high school system just after WWII . It was surplus property that the state had . Most of the high school shops were equipped with old defense surplus available from the State of Montana .
The 40 plus years the high school kids had to wear and tear it did take it's toll . The thread counter is missing , carriage lock missing , back gear has a tooth missing and a matching tooth on the head stock. Labeled as a 9",4' bed . The drive is flat belt with 3 steps . Motor is below the base cabinet. Reverse switch not hooked up properly ,probably because motor is an old Craftsman 1/3 hp 1725 RPM 115 volt. Either way you flip the switch it runs forward. I bought it 30 years ago @ school auction , They had bought 2 new lathes and sold off two old lathes . I wanted the other one as it had quick change threading gear box .And had a 3 jaw chuck. This old one had a face plate and a dog leg holder. It seems to me it cost more for the 4 jaw chuck then I paid for the Lathe. The old V ways are in good shape .

Cat Whisperer · « **Reply #25 on:** March 18, 2009, 03:36:02 PM »

As the saying goes, 'all new machinery is made on old machinery'.
It's an American tradition to get the job done with what you have; improve on it next time ... repeat.

warf73 · « **Reply #26 on:** June 05, 2009, 01:24:41 AM »

How is this project coming?
I'm wanting to build a BB cannon, I've got the cylinder and about 40 bowling balls.
Wasn't sure if I needed a chamber or not. Seen several on YouTube and none of them seemed to have a powder chamber (I'm not sure).

Warf

Double D · « **Reply #27 on:** June 05, 2009, 03:18:35 AM »

Yes build a chamber.

Here is the finished product. http://www.gboreloaded.com/forums/index.php/topic,175052.0.html