Cannon vent.

[Titus]

My plans on building my own cannon are coming right along. Worked on the diagrams and illustrations of the carriage wheels from 20;00 until 00:35 last night.

The cannon barrel is almost 700mm in length and has a 20mm bore. What I need to know is whats the ideal or rather correct dia for the flash/vent hole into the breech?

 

[Titus]

I found a reference stating a vent diameter of 0.200". Any comments?

 

[CU_Cannon]

A vent size of 0.2 in was for the most part universal during the American Civil War. It works well for most forms of ignition.

 

[Titus]

:bow: :hatsoff: Thanks CU Cannon.

 

[GunneyG]

I would make the vent diameter just large enough to be able to easily remove the remnants of your ignition device after firing. A vent that is appropriate for a 3" or greater bore will let a lot of the pressure out of a .8" bore. If you are just making noise, that won't matter, but if you are launching shot, it will.

 

[TheDoubleD]

Titus a rule of thunb for vent hole is 1 1/2 calibers.

If your fuse is .200 diameter, one caliber is .200, 1 1/2 is .300.

 

[Titus]

My plan is to make the cannon bore a 20mm with a percussion system firing musket caps. I found a "cannon hammer and lanyard" at Dixie Gun Works for about $22.50. :v

 

[xxgrampa]

if you are going to use a musket cap, .070" is plenty big.. even at that, it mite recock the hammer :grin:

..ttfn..grampa..

 

[ricklandes]

I have used that system and find that tying the lock on with a long flat strap of leather works well to hold it in place. I would suggest you try the lock a few dry runs with cap only so as to get a feel for the snap of the wrist needed to pop a cap and not snap a pull line. Bending the lock base to the arc of the tube is not required when setting the lock with the leather strapping. Make it long enough to wrap around the cannon about 3 times, plus knot (1/2 granny works fine). I keep the leather fairly supple (neatsfoot)to aid the leather in "sticking" to the tube.

I drill out the musket caps to about 5/64 for our 1.5" bore. Also use a bottom tap so as to avoid another pocket for resudue to build up.