Author Topic: Ignition by percussion cap (Read 1950 times)

Cat Whisperer · « **on:** July 04, 2003, 02:28:11 PM »

I am looking for designs (so's I can build them for myself and production) for a simple ingnition system for black powder mortars.

I would like it to use percussion caps.
I do not want to have to cock it against spring pressure, but use the movement of a hammer of sorts to hit the percussion cap. This keeps the design very simple.
Method of attachment is up for grabs.

What pictures do you have? Are there any patent drawings?

Double D · « **Reply #1 on:** July 04, 2003, 06:32:35 PM »

This

Is available here
http://www.cannon-mania.com/cannon_lock.htm

as listed in our Cannon shooters resource list...

Cat Whisperer · « **Reply #2 on:** July 05, 2003, 02:11:28 AM »

DD -
Thanks for the lead. Brass looks good too. (and I've got lots of small scraps as candidates) The dimensions give perspective of size to ensure that it works when built.

mwarnick1 · « **Reply #3 on:** July 08, 2003, 10:56:04 AM »

From the picture it looks like you tapped the nipple right into the side of the mortar. It also looks like the screw holding the brass assembly in place is also drilled and tapped into the sidewall.

I wanted to do this but was concerned about weaking the sidewalls. Will these modifications weaken the mortar tube?

Thanks,

Matt

matt_warnick@hotmail.com

Double D · « **Reply #4 on:** July 08, 2003, 11:14:56 AM »

That nipple has to go into the vent hole where the fuse would go.

As far as the screws for mount go, they are only going in at the most a 1/4 inch if that deep. The walls of your should be substantially thicker. Not even a factor if you have built you mortar according to the safety specs laid in in the two documents on safety sticky'd at the top of this forum.

Calamity Jane · « **Reply #5 on:** July 08, 2003, 12:16:48 PM »

So lemme get this straight.....

The nipple scres into the priming tube (I assume there's a removable tube screwed into the barrel) 'n' ya don't use no priming powder - just let it flash into the main charge?

(Fuse is hard to come by up here so I been watchin this thread with GREAT interest!)

CJ

Cat Whisperer · « **Reply #6 on:** July 08, 2003, 03:35:47 PM »

Let me take some educated guesses and make a comment or two. First, it would be impractical to remove the nipple each time one fires; therefore it would seem that it would fire directly into the main charge.

Two issues. Is the cap (assume a musket cap which is larger than on blackpowder rifles or pistols) going to ignite the cannon powder (coarse) reliably? Is there any risk of sparks residing inside the priming hole?

Having a nipple screwed into the hole would preclude anything of any size from clearing the hole after each shot.

BUT, there are people that use these things, so what are the reasonable assumptions.

I have seen pieces of fuse gloing brightly 2 (TWO) minutes after firng, inside the powder chamber. But then, with a musket cap, there would be no fuse to keep burining. Strict adherence to the minimum time between rounds should also help.

Matt - If you're concerned about placing screws into the tube, then do one or both of the following:
Offset where the screws are to a portion of the barrel that is not directly around the powder chamber, and / or drill only 3 or 4 threads deep and use the bottoming tap (which will cut the threads to the bottom of the hole) so your holes are minimal. It's common practice to place scope mounts directly above the chamber in rifles, so the effect of a couple of smallish holes of minimal depth should be minor.

Double D · « **Reply #7 on:** July 08, 2003, 06:30:35 PM »

The musket nipple is drilled out and FFFFG is poured down the vent hole through the nipple. Or, a paper straw fuse is pushed down the drilled out nipple into the vent hole.t

If you look at the safety rules you will see that there is a set procedure for swabbing and worming and it applies to the vent also. this is to clean out the burning embers and stuff.

Cat Whisperer · « **Reply #8 on:** July 09, 2003, 01:10:02 AM »

DD -
Excellent response!

A. Someone speaking from EXPERIENCE and,

B. Someone who's read the safety rules well enough to REMEMBER and,

C. A direct answer of procedure that answers all the posed questions.

Thanks,

Jeff B. · « **Reply #9 on:** July 09, 2003, 03:09:55 AM »

Calamity Jane:

If you find fuse hard to locate, another alternative would be to make your own. It's a very simple procedure that wont take much time to do and you'll make more than enough fuse to last you a long time. Here's a link describing the procedure.

http://www.unitednuclear.com/crossmatch.htm

For me, meal black powder is harder to find than fuse. I substituted Pyrodex RS for the meal powder and it has burned cleanly and consistent for me. I haven't tried it in my cannon or mortar yet but I'd have no doubt that it would do the job.

I had a hard time understanding what dextrin was until I did some research on it. I'm using malto dextrin which can be purchased in bulk from any home brewing/wine making store. It's a white powdery substance with some similarity to corn starch.

Two things to keep in mind while making your own fuse:

(1) Let the mixture thoroughly soak into the cotton string before removing from container.

(2) Let the fuse dry out for a minimum of 3 days before using. I experimented by trying to light the fuse too soon before it had a chance to thoroughly dry. Understandably, the results were poor and ignition in certain spots of the fuse was weak or failed to ignite. Not a good thing.

It's a cheap and effective way to make your own fuse. Try it for yourself. It might satisfactory for your needs.

P.S.: With every new batch of fuse you make make sure to test a sample piece to ensure that the burn rate is consistent with previous batches. You don't want any sudden surprises when you touch off that cannon of yours.

Calamity Jane · « **Reply #10 on:** July 09, 2003, 05:05:22 AM »

Thanks Jeff!

I found the fuse-making instructions over at http://www.pyrouniverse.com/fprojects/blackmatch.htm

If I can't find fuse, I will make it.

CJ

mwarnick1 · « **Reply #11 on:** July 09, 2003, 06:38:59 AM »

Thanks for the idea of offsetting the attachment screwholes to a non-critical portion of the tube. Sometimes the answer is so simple that it takes someone else to point it out! <grin>

My main concerns were:

a) that the nipple would turn into a projectile upon firing and launch out of the side of the mortar.

or

b) that tapping the fuze hole would somehow weaken the tube.

Upon more thought I think I was being overly paranoid.

Most of the time I fire the mortar at large gatherings so I've been erroring on the side of more caution than usual.

Matt

Cat Whisperer · « **Reply #12 on:** July 09, 2003, 09:29:42 AM »

Matt -

You mentioned firing at large gatherings of people. I agree, much fun.

I'll never forget my boss (on seeing the 4.5" mortar fire) who was an avid motocross nut saying, "That's the coolest thing I've ever seen!"

Ahhhh the pleasures of givng out the adrenaline rush!

It's always a good idea to keep people out of the way of the line of trajectory from the fuse hole.

Double D · « **Reply #13 on:** July 09, 2003, 01:07:47 PM »

I have no self control...

Matt said

Quote

Most of the time I fire the mortar at large gatherings so I've been erroring on the side of more caution than usual.

CW said

Quote

You mentioned firing at large gatherings of people. I agree, much fun.

Do they ever fire back... :-D

mwarnick1 · « **Reply #14 on:** July 10, 2003, 07:03:41 AM »

Do they ever fire back?

If they fired back that would take all the fun out of it!

<grin>

Matt

Calamity Jane · « **Reply #15 on:** July 12, 2003, 02:54:22 AM »

Quote

offsetting the attachment screwholes to a non-critical portion of the tube

Where would that be? Not trying to be a smarta@@, but but all of the tube is subjected to the pressure of firing. The thickest part of the tube would be the strongest.

I LIKE this idea, ignition by percussion cap. It seems SO much more reliable and predictable. From "decission to fire" to firing is only a fraction of a second. With a fuse, it's hard to change your mind if something happens after you touch the match to the fuse.

I'm going to see if I can't figure some way to use the fuse tube as the front attachment for the percussor (NEW term!) with one small screw at the rear to prevent it from turning. That would allow the switch-over to a conventional fuse with only one small hole visible.

One could always attach the percussor with "oversize hose clamps" and allow it to index on the nipple. That would leave the appearance uneffected when it wasn't in use.

CJ

Cat Whisperer · « **Reply #16 on:** July 12, 2003, 06:44:45 AM »

Quote from: Calamity Jane

Quote
offsetting the attachment screwholes to a non-critical portion of the tube

Where would that be? CJ

I'd put two screws to hold it right behind the touch hole. Since the bore ends rightabout at the touch hole it would be subject to much less pressure.

Another alternative to the mounting system that I'm toying with is a magnetic base (if the tube is iron).

Double D · « **Reply #17 on:** July 12, 2003, 11:28:04 AM »

You aren't going to drill and tap any holes deep enough on cannons that are big enough for a percussion lock to cause any structural weakness. That is if you are drilling 1/8 inch or even 1/4 hole vs 1 or 2 inch hole.

you should how deep some holes are on gun barrels when we driil and tap for sight s. And remeber, snokless generetas much higher pressures tha black.

That cast iron around that steel inner is for decoration and only provides minimal strength to the gun.

If you have ever seen the real thing they have all manners of holes for fitting locks and sights and stuff.

Just keep in mind this percussion lock is for larger heavy guns. the smaller guns will move when you snap the lock.

Calamity Jane · « **Reply #18 on:** August 18, 2003, 09:39:17 AM »

Whal, I figgered a way to mount a caplock on me cannon without drillin extrie holes in the barrel - go have a look-see in the "Caplock" page over at http://www.geocities.com/diannebest/Cannon/Cannon.html

It ain't purdy bronze, like the ones ya kin buy, but it works 'n' only took a few pieces of steel from the scrap bucket! (I just HAD to pop a coupple of caps, doncha know :shock: