Bowling balls - ITS ALL YOUR FAULT!!!

[Cat Whisperer]

Out yard sale-ing today.  Found 5 bowling balls for $1 each.  Mentioned that to a friend at work - he's going to GIVE me a CO2 cylinder (if it's the right size).  You KNOW what's coming next.  Darlene (my rib) didn't even raise and eyebrow!  (Mortar #25 - like I NEED another one - how do you spell addiction?).

[Cat Whisperer]

Out yard sale-ing again.  Stopped off at a friend's house & he GAVE me an oxygen tank (THANKS BERT!).  It measured right at or a whisker below 29.5" in circumfrence.  Hit the flea market and picked up ten 4" x 1/16" cut-off wheels for $1 each.  Now to see how much I have to do to modify them to fit my Milwaulkee hand grinder.

Now the decisions.  

1. What style for this thing to emulate?  Should it be histerically accurate?  Could I build a huge wooden tube around it to make it look like The Dictator?

2. How long a tube?  I have easy access to 100 and 180 yard ranges.  I would make quite a splash out there in the lake though.  Is two calibers enough?


3. Design of the powder chamber.  There are several methods of doing it.  In light of wanting basically a 100 yard mortar, what is the most efficient way of minimizing the amount of powder for this range/bullet weight?

Your comments are invited.  I am going to record this process as well.

[Double D]

CW
Go for the two calibers, put faux bands around it.  Make faux reinforce and trunnions out of flat stock, weld around neck and round top of bottle..

When do you want me to bring a couple of these oak planks down?

What size do you need...

6-2"x12"x 8'
3-2"x8"x8'
1-1"x8"x8'
1-2"x14"x8'

Do you have somebody down there with a big lathe that could take 12  in. long piece of 6 inch stock with an  8 inch deep 2 3/3 in hole in it, that could open the hole to 3 inch?

[Cat Whisperer]

DD - interesting thoughts.  A friend has plenty of schedule (real-thick) 10" pipe from which to make the 'reinforcing' bands.  Agree with you on the trunions attaching to them.

Check your email - I've sent 7 pix of MY lathe setup.  Will be able to do the work when I've got a steadyrest large enough - existing ones only handle up to 4" diameter.  Headed in that direction though.  

Boards - not ready yet.  Design still in flux.

I'll post some of the pix of the lathe setup in a new thread.

[Cat Whisperer]

Oh the frustration!  (&*$#!)  It would be easier to remove this whole thread that to admit that I can't measure worth two hoots.  On second mearsurement (after cutting) the tank wasn't 29.5" in circumference!  Nice gong though.  I will find a practical use for it someday.  Until then the hunt is on (again) for a tank.

[Double D]

Okay,so bowling balls won't work.  What is the inside diameter and lets start looking for projectiles!

[Cat Whisperer]

The walls are just a whisker above 1/4" thick and the sparks when grinding were redder than 4140.  I'll measure the ID.

The inside follows a nice clean curved flowing line to the valve.  I tried removing the valve with a 15" crescent wrench and a 3 lb hammer to no avail.  I do like the curve for a smooth expansion of combusiton gasses; so that means I'll consider adding the powder chamber to the rear.

Perhaps a 'canister' round of 2 liter bottles banded and supported underneith with an 8" disk of 3/4 plywood?

[Cat Whisperer]

ID - very interesting.  The tube is a bit out of round.  8.62 in diameter at the largest, 8.5 ish or less elsewhere.

But if 8.5 is a good dimension (minimum) then IF they make 8" pvc pipe with 1/4" wall thickness....

There might be hope yet for readily available ammo.

[SLEEPY BEEPER]

This is a long shot but. My O2 tank was small and out of round at the bottom (bowling ball would not go in). At the top (by the valve it was rounder and bigger. There is a small chance if you cut the tube shorter a bowling ball may go in. By the valve end the steel is 3/4 inch thick. This might hold it rounder. I don't know how to check for this. Maybe cut a stick that is the same length as a bowling ball. And see if it will fit up inside? If the stick will rotate around inside the top end. Then just cut it shorter.

[Fred]

Ref. tanks, they may have been hydrostated and were rejected because they streched (out of round) during the test.  Thats what I found out with  my first tank, Hang it upside down, it makes a great gong.

I think that some gas tanks may have opesite threads(depending on the type of gas it contained) but I''m sure you guys know that.

[Cat Whisperer]

The tank in question was rumored to have been in a flood - hence could have been handled by the currents like everything else floating down stream.

The only bright spot so far is that the bottom end has made a substantially strong stand for my anvil - just about the right height and very stable.

[Mike Scott]

Is there any reason the "bottom" end of the tank could not be used for a mortar tube?  I know it would not have a reduced chamber but it would give you a sealed tube without needing a threaded/welded plug.

[Cat Whisperer]

Is there any reason the "bottom" end of the tank could not be used for a mortar tube?  I know it would not have a reduced chamber but it would give you a sealed tube without needing a threaded/welded plug.

The whole concept of a Coehorn design is to have the thick steel around the powder chamber where the highest pressure (a spike) occurs.  IF that could be added, I see no reason for not doing it.  [That is theory, and should be treated as such.]  The wall thickness appears to be a whisker more than 1/4" in the middle.  It MAY by itself handle the pressure (another unknown).

[SLEEPY BEEPER]

Try an old Brunswick bowling ball. They seem to be smaller then others. Some of the new shinny fancy colored balls will not start in my mortar. Old Brunswick balls (the black ugly rubber ones) drop in with good windage. The fancy ones that don't go. I take outside (this is messy) and grind down with my 4.5 inch sander/grinder. Then I shoot them into the river. Love to hear them hit.