Newbie needs your suggestions!

[buckrun]

A long while ago, a friend had a cannon he let me use for the 4th, and I got hooked! I recently acquired a 4.5" dia x 22.5" piece of solid billet steel that used to be the bearing shaft on a large piece of mining equipment. I want to machine it into a Here is where I need your suggestions. I was thinking of a golf ball howitzer due to the availability of cheap ammo. I have to keep things relatively inexpensive.  I got a price from a local machine shop to mill out the bore to 1.723 inches, 20 inches deep for the golf balls. ($170.00) I was thinking of milling in a "fuse hole" that will accept a 209 primer and some sort of spring hammer device with a pull cord for the ignition. The machinist said the metal was in the 30-35 hardness range. Is this a good diameter for this piece? Can I also shoot lead and zinc? How should I attach the trunnions?

What would you do?  I thank all in advance for any good suggestions you give me!  Great forum! I got through 30 pages last nite?

[Double D]

30 pages of this board list night....You must have ultra high speed cable!!!

First the basic safety rules say the maximum bore for your piece of steel is  1.5 inch.  Breech wall thickness should be equal to the diameter of the breech.   4.5 /3 = 1.5 inches.

Shot gun primer firing might work. But might not.  You might have too prime the vent first with FFFFG.  Will the fire from the primer consistantly reach 1.5 inches and fire the powder?  Try it and let us know.

[Cat Whisperer]

WELCOME!

Consider keeping the fuse hole small (to limit escape of pressure) and enlarge enough for the 209 only at the top.

Fro around here that is a good price!

[GGaskill]

I recently acquired a 4.5" dia x 22.5" piece of solid billet steel that used to be the bearing shaft on a large piece of mining equipment...I was thinking of a golf ball howitzer due to the availability of cheap ammo...I got a price from a local machine shop to mill out the bore to 1.723 inches, 20 inches deep for the golf balls.

That would be a good match for the piece you have.  To get around the wall thickness=bore diameter rule, you can simply use a 1.5" powder chamber (howitzers generally were chambered anyway.)  This means that the bore would need to be drilled (not milled) with two different drills to produce the stepped diameter.  The chamber area wouldn't need to be very long to contain a reasonable charge for the bore diameter.  If you went with the chamber, firing zinc shot would be practical.  Even 1 lb lead shot would be OK as long as you don't use too much powder.

[buckrun]

Dear Friends,

Thanks for the great advise! I think I will use all of your suggestions! Especially helpful was the advise on the vent hole and powder chamber.

What would be the safest and most practical way to attach trunnions? Should I drill, press fit and weld? Would that affect the integrity of the barrel? How deep should I go with the 1.5" dia powder chamber?

Thanks again!

[GGaskill]

My trunnion attaching preference is to mill flat bottom pockets in the sides of the barrel and fit close slip to light press fitted trunnions with rimbases into the holes, then TIG weld the joint.  Details depend on the details of barrel profile at the point the trunnions are fitted.  I like to leave at least .5" wall thickness under the trunnions which is plenty from a pressure perspective as the gasses have expanded several times by the time they get there.