Author Topic: Help reenactors with decision on vent placement (Read 5103 times)

cannonmn · « **on:** November 28, 2009, 01:06:07 PM »

A reenactment group has asked for assistance from experienced persons, regarding placement of the vent in their new cast-iron reenactment cannon. There are two options shown below, that they are considering.

I've already asked them about a seamless liner, and I don't think they are planning to install one since they are going to shoot blanks only, and not within any organization which requires liners. However I have informed them it is a requirement in NSSA, for example, and it is a good idea in any case.

However, assuming they are going ahead as-is with no liner, which of the options shown below is the best, the angled vent hittiing the chamber well-forward of the rear, or the right-angle vent, hitting the chamber very near the rear wall?

I am uniquely unqualified to advise them on this since I don't built replica cannons and have never been faced with this question before.

Option 1:

Option 2:

BoomLover · « **Reply #1 on:** November 28, 2009, 01:26:12 PM »

IMHO, option #1 is better.

cannonmn · « **Reply #2 on:** November 28, 2009, 01:29:07 PM »

Quote

IMHO, option #1 is better.

Thanks. I should have also asked, if you have a preference, why that option is preferable.

seacoastartillery · « **Reply #3 on:** November 28, 2009, 01:29:31 PM »

3/16" is way too close, because a cartridge punch can glance off the end of the cartridge, pushing it forward slightly and FAILING to open a channel to the powder to be ignited. The angled vent would preclude this from happening. We also would still insist on installing a liner for safety, making the necessary adjustments in the bore's depth to make the vent come out at least 2/3" above the liner's bottom.

Mike and Tracy

Double D · « **Reply #4 on:** November 28, 2009, 02:17:28 PM »

Without a liner, drilling a vent in this cannon is not safe. Blanks or not, re-enactment our not. If it's possible to load a projectile it will be loaded!

RocklockI · « **Reply #5 on:** November 28, 2009, 02:30:58 PM »

.."... Jesus Johnny ! "

. Measure one of the 15 million and some odd number of guns you have just laying around ......?

.

Personaly Id punch that bore back a smidge and go straight 90 % down with a #2 type idea . ESPICIALY if they are not going to use a liner . It is the strongest IMHO . BUT as always I could be wrong , but Im not .

Looks like some extra meat back there for punching into . If that can't be done #2 is the only way to go .

Gary

Articifer Tom · « **Reply #6 on:** November 28, 2009, 02:59:32 PM »

Neither is safe . A liner is a must!! also a vent liner a must!! making number 2 easier.

Artilleryman · « **Reply #7 on:** November 28, 2009, 03:06:44 PM »

I think it would be easier to accurately drill a vertical vent, just move it forward slightly. Also, a vertical vent will make it easier to put in a vent piece that is flush with the inside of the bore. I agree with the other posters who have said that a bore liner and vent piece are a must. Much better to be safe than sorry.

KABAR2 · « **Reply #8 on:** November 28, 2009, 03:13:28 PM »

They may be working on a budget trying to do this, I have to assume this is a cored gun to save money on drilling a bore,

as others have stated this is a bad idea, ask them if they have group liability coverage? they need to let their insurance know

they intend on adding artillery to the mix or they will not be covered in case of an accident, the insurance company if experienced

with re-enacting may have requirements for a liner & vent bushing. they need to go the added expense for their own & others safety,

As to vent location the further angled vent would be better, if someone places an aluminum cartridge in backwards (thick side to the breech)

they would not be able to prick the cartridge only the foil and after several misfires may decide to pull the charge with the worm, not a desirable situation.

Allen <>< - retired from re-enacting 1991 -Non Com & later Officer in El-Regtemto De-Louisina 1979 to 1984
other units 1984-91

A.Roads · « **Reply #9 on:** November 28, 2009, 03:25:35 PM »

Re-enactors often find themselves firing a range of blank sizes depending upon what the situation is, problems can arise with loading & igniting small charges. With a reasonably small bore of 2 1/4" they do not have the problem encountered with large bores using small blanks whereby the blank charge may be of greater diameter than length & "falls over" in the bore when being loaded. With a 2 1/4 inch bore they will probably want to use a charge 2 inches in diameter & 3 inches long. Such a charge will probably hold more powder than they will want to burn & in which case only a portion of the charge will be filled. Typically this will be a foil cartridge with attendant folds of foil taking up some space - this will be problematic if the vent hole is too close to the breech face. I'd suggest that the vent hole should terminate 3/4 to 1 inch from the breech face. Really there is no difference in vent location for a SBML for live or blank firing.
I am in group & we annually fire some 9" RML Armstrong guns. The cardboard blank is huge, 8" in dia & about 20 inches long, one end is sectioned off about 4 inches long & one kilo of powder is poured into this. The touch hole is a long way from the end of the bore & locating this 4 inch piece of the charge under the vent takes some skill, when it does not align & fails to ignite one has a fairly serious problem to overcome with hundreds of spectators as witness - we haven't had that experience yet thank goodness.
Adrian

subdjoe · « **Reply #10 on:** November 28, 2009, 04:06:32 PM »

If I knew that there was an unlined cast iron gun on the gun line, I would think real hard about sitting out the battles. Not to mention that if it should at some time in the future be sold to someone else who tries live fire, they may be selling a pipe bomb.

Look at it this way - the outfit who made the barrel didn't drill the vent. Why not? Liability. If the outfit that built it isn't willing to risk it, why would you want to?

KABAR2 · « **Reply #11 on:** November 29, 2009, 12:43:09 AM »

one other consideration if the gun was cored, has the bore been smoothed up? any rough spots or inclusions
in the bore especially at the breech could keep a hot ember alive even with sponging. It is hopeful that the
re-enactment group will be reading these, and join in to the discussion, they could clear up a few things this way.

Cat Whisperer · « **Reply #12 on:** November 29, 2009, 02:11:01 AM »

I hope the sketches of the interior of the bore are symbolic.

The sharp corner would be a stress riser! More likely there is some rounding, which would be stronger.

I would place, whatever the angle, the entrance of the touch hole into the bore further (rather than closer) from the inside corner for reasons of strength.

dan610324 · « **Reply #13 on:** November 29, 2009, 09:51:12 AM »

I would prefer option no 1
but if the drawing is correct the wall thickness is less then the bore, thats a big NO NO
cast bronze had a minimum 1:1 ratio
cast iron had a 1,25 - 1,5 : 1 ratio
so the dimensions is a big NO NO
sharp corners is also a NO NO , even if many original cannons was made that way
but back then it was an acceptable loss that a few cannoners was blown up during a fight by their own exploding cannon , today it isnt

would be interesting to know if its cast with a core or machined
it really doesnt matter but would be interesting to know , its still a big NO NO

I dont know who designed it , but it sure aint safe to fire that piece with or without projectile
do they even know what type of cast iron its made from ??

JOHN PLEASE TELL THEM TO READ THIS SUGGESTIONS AND CONTINUE THE DISCUSSION
Im sure they need to learn a lot about designing and building cannons

artillerybuff · « **Reply #14 on:** November 29, 2009, 05:08:14 PM »

I agree with all the above about this piece NOT being vented at all, it must be lined or regulated to ornament duty only, period!

An angled vent is very undesirable:
1) The primers tend to pop out when the lanyard is pulled.
2) Picking the charge can move the charge forward.
3) The friction primer tubes blow straight back to the ammo box.

Vents should be drilled straight down and enter the chamber 1" ahead of the back of the breech. This will reach even the lightest of loads with 100% reliability.

I have used cannons with both types of vents and I dislike the angled ones very much. If I am not mistaken, they stopped drilling them that way once Friction Primers became common.

Anthony Variz

KABAR2 · « **Reply #15 on:** November 29, 2009, 08:41:46 PM »

Quote from: artillerybuff on November 29, 2009, 05:08:14 PM

I agree with all the above about this piece NOT being vented at all, it must be lined or regulated to ornament duty only, period!

An angled vent is very undesirable:
1) The primers tend to pop out when the lanyard is pulled.
2) Picking the charge can move the charge forward.
3) The friction primer tubes blow straight back to the ammo box.

Vents should be drilled straight down and enter the chamber 1" ahead of the back of the breech. This will reach even the lightest of loads with 100% reliability.

I have used cannons with both types of vents and I dislike the angled ones very much. If I am not mistaken, they stopped drilling them that way once Friction Primers became common.

Anthony Variz

This is a 18th Century gun so no friction primers, they could use quills but most likely loose priming powder fired by linstock or portfire,

so angled vent is not so much an issue,

artillerybuff · « **Reply #16 on:** November 30, 2009, 03:16:38 AM »

Agreed, however, I have seen people use friction primers in Rev. War and older pieces. It can still be done safely, just wanted to point out the draw backs and what to watch out for.

RocklockI · « **Reply #17 on:** November 30, 2009, 03:19:28 AM »

I thought the Navy didnt use copper primers ,because of bare feet ?

gary

cannonmn · « **Reply #18 on:** November 30, 2009, 03:41:42 AM »

Quote

I thought the Navy didnt use copper primers ,because of bare feet ?

The Army used brass tubes, Navy used quill primers made of bird quill for bare foot safety as you mention.

Some comments above have assumed this tube was to be used in naval reenactments, but that's not the case. My understanding is that they'd portray a field artillery unit.

Cannoneer · « **Reply #19 on:** November 30, 2009, 09:11:38 AM »

Cannonmn,
If I were asked this question by would be reenactors, my straightforward advice to them would be to put off making a decision on the angle of the vent until a competent craftsman had installed a properly constructed seamless steel sleeve in the cannon, because if they fired it (even with blanks) before this was done they'd be placing their lives and limbs in jeopardy.

cannonmn · « **Reply #20 on:** November 30, 2009, 09:36:07 AM »

Thanks. One other option since I think they already have money sunk into this tube is to fire it using other-than-blackpowder, which gets to the gun via hoses, but which as I'm aware we can't discuss on this board since those gases are not blackpowder.

dan610324 · « **Reply #21 on:** November 30, 2009, 09:38:45 AM »

anything that explodes make pressure , doesnt matter whats used it still could be dangerous

rampa room artillery · « **Reply #22 on:** November 30, 2009, 10:32:04 AM »

option #2 is best but should be farther forward and should be lined, stainless steel.

Rick bryan
NSSA

cannonmn · « **Reply #23 on:** November 30, 2009, 11:30:25 AM »

Info from the group, should make us feel a wee bit better, even though the liner isn't 3/8 inch, is better than nothing. Note that this cannon was cast right on the core (liner) instead of being cast solid, drilled, then lined as most of the lined guns I've heard about. I have not dealt much with cast-on-core guns, has anyone else?

RocklockI · « **Reply #24 on:** November 30, 2009, 11:45:55 AM »

Well John , in that case you can put my suggestion into the ....'never mind' file . it was fun while it lasted !

Gary

dan610324 · « **Reply #25 on:** November 30, 2009, 01:19:57 PM »

I read 1/4" but in the drawing it shows 1/2"
spanish ??
could be our south american friend dr Oswaldo Gatto who made it
probably a good gun for blanks , but what would happened if it by any reason would be fired with a projectile of a future owner ??
maybe nothing , maybe a disaster
but at least this board got him to use seamless tubes , so we know that we at least does some good

Indygunworks · « **Reply #26 on:** February 07, 2013, 05:53:02 AM »

I know this is an old post, but this is a HERN IRON WORKS cannon barrel which as far as i know are held in somewhat high regard by this forum as being safe barrels. It also happens to be the exact barrel i have on order. I am going to be venting mine here in a few weeks and thought i would ressurect this thread. I think drilling my vent vertically will help alot w/ installing my vent liner accuratly.

are there any new thoughts on this? what size bolt should i use? what size hole through the middle if i plan on using a slap hammer w/ musket caps?

Also, am i correct in assuming that i dont want my bolt (vent liner) to completely enter the bore? With only a 1/4 inch liner whats the best way in getting the bolt to the proper depth?

Double D · « **Reply #27 on:** February 07, 2013, 06:27:23 AM »

Quote from: cannonmn on November 28, 2009, 01:06:07 PM

Option 1:

I can not find any legitimate reason for not drilling shown in option 1. In one sense it would even be safer. See your other post asking for help.

Contact AOP and order a copy of their vent liner drawing.

I drill my vent liner holes all the way through and use muffler gasket sealer in the threads. That is my one concession to cutting corners on this. Original liners were copper and went into a seat in the bottom of the vent hole and I suspect the vent liners were design to crush fit and seal, absent modern sealants. Here is a vent taken from Matt Switlik's book, The More Complete Cannoneer. I added a line drawing to show how it worked. You will find this vent liner drawing in most AOP plan books.

The hole through the vent liner was .200. Depending on what you use as an ignition source that dimension might very slightly. See my other reply to your other post for other dimensions.

Indygunworks · « **Reply #28 on:** February 07, 2013, 07:06:55 AM »

You say option number one is better, but your drawing shows a verticle vent. Would it be better if i can locate my verticle vent so i have around 1 inch away from the rear of the chamber? Wouldnt that be the same as option number one? A few people in this thread have said a verticle liner would be easier, and possibly better.

Also, is a stainless steel bolt the way to go for this?

Thinking, a course thread stainless steel bolt, using gasket maker to seal everything off, but what size bolt?

Since this is a cast in place liner there could be some variations on where the liner is actually located in the cast iron, so drilling straight down will allow me to keep peeking and drill until i can see the drill bit enter the bore. that will give me my depth to the bore which i can then subtract .125 from when i drill w/ the larger drill bit that i will use to tap the hole. Fill all that up w/ some gasket maker and it should seal off rather nicely.

I for the life of me cannot figure out why i would want to go through all the extra steps of angling my vent liner if i can go vertically just as reliably. I will put my vent hole 1 inch forward of the rear of the chamber though.

seacoastartillery · « **Reply #29 on:** February 07, 2013, 07:45:22 AM »

The way we see it, Indygunworks, the very first thing you have decide is your method of ignition. You did mention musket caps. The problem with these is not that they won't fire the powder charge, but that they don't allow a thorough cleaning of the vent which should be completely cleaned after each shot. No matter how much you open up the nipple, you can't open it up enough to have an unobstructed hole all the way down to the charge. AND, who the heck is going to unscrew the nipple to clean the vent completely during an event?? NOBODY! With a slap-hammer, power cartridges used for driving concrete nails are 100% sure-fire and easy to remove. 209 primers are also very good, but can be difficult to remove.

Make this ignition type decision first, then consider size of drills, etc.

Hope this helps,

Mike and Tracy