Does anyone know off hand where I could come across some type of plans for the basic Indiana style cannon. I've been trying BDER/C for a couple weeks now to no avail[]. I would just like to see something in detail of a design that already works -- I really don't want to have to re-invent the wheel from scratch. Kotori had started an excellent post at one time, but it got a little sidetracked a few pages in. Thanks!!
I don't recall for sure, but Carl (kotori) may have some cad models he can post drawings of. Do you need the general principle of operation, or do you need specific dimensions? Specific dimensions vary from person to person and from ship to ship (except BDE cannons, which are made at a professional machine shop). There is a cut-away animation that shows the general operation of the standard rotating Indiana cannon, I think it's been posted on the forum before. Edit: NooNoo posted the link to the animation
Thanks Gascan and NooNoo!! Yes, I've seen the GIF that shows the general principle of operation. Although as you mentioned, specific dimensions are't really required, I would like to see a little more detail than the GIF animation shows. I guess it would be helpful to see the different parts and how they interact with one another. You know , basics of construction... Like the best angle for the balls to roll down to the breech area, how far the balls overlap the first ball in the breech, how the magazine cover fits over the barrels that extend from the breech, what should be airtight and what shouldn't... so on and so on. The rotation and elevation aren't a problem, I'm a little foggy on the Voodoo that goes on in the breech/magazine area. Not that I can't figure it out on my own eventually, but CNC machine time is a premium, so if I could eliminate as much of the trial and error ahead of time, I can get in the water that much quicker, without begging to borrow the company's machines so much (they kind of frown on it -- a little bit of usage is probably not too much trouble, but three or four Saturdays in a row... a definite problem!!). I suppose I should mention that I am planning an Iowa class, so there would be 3 barrels per mangazine. Any help or links anyone could provide would be much appreiciated!!! Thanks!!
There ain't much out there on cannonmaking... I have some thoughts though. Angle... try 20 to 30 degrees. Or, pick a good point that gets you in the magazine base, but doesn't drill through the side wall and calculate how to converge .020 or so above the bottom of the magazine. I may be off on my estimate, it's been awhile. You've got to allow material to make a good seal when the ball is ready to be fired, and to position the ball without it falling into the manifold to avoid problems when fired. Ball overlap... there will be a void under the magazine where the manifold is either milled or turned out. A set screw centered on the riser's through hole, but in the manifold raises and lowers the firing ball in relation to the balls in the feed/magazine. I haven't yet figured out any hard and fast rule. You may have to adjust the height to prevent two balls from firing per shot. Argh!! terms!! I call the manifold the part under the magazine that holds the bearing and adaptor to the accumulator. It will have a through hole and 4-40 threaded holes per the barrels of the design. It has either a concentric hole to allow air to all the risers, or individually milled air passages. Individually milled passages seem to me to be more air efficent. Depending on the method of attaching the adaptor it will also have holes for screws, typically two. Indiana cannons typicaly have three holes to attach the magazine and manifold. Use a coarse thread! I'd say 1/4-20. Too fine a screw or thread here will not make your day. Adaptor... A tube turned to hold the bearing and fit into the accumulator. Bearing can be made tight to the adaptor by leaving a little length over, and pressing with a 45 angled rod. Note on risers: These are typically stainless or brass and are press fit to the holes in the magazine. Of course, you've got to use a spacer of some sort when pressing so the riser does not overlap the feed. Roughing the riser with a dremel and epoxy here can help too. There needs to be a retaining lip, either pressed in, or machined. I have guns where this was made by soldering on extra brass... but I am not sold on that technique. For the barrels: It helps to call the first portion of the barrel system the riser. The risers fit through holes drilled oversize in the magazine cover. The barrels are then attached with flexible tubing so you can depress them. The holes for the magazine cover usually are oversize to fit this tube. You will need a sealed bearing... if it's not air gets out There used to be available a bearing with a E clip and the easy attachement was to grab this ledge with screws. It is now hard to find this bearing. Note on magazines... You will want to add a slight angle so the balls preferentially roll towards the feed holes. On large diameter mags turned manualy, it is easy for heat to cause problems... and the center ending up raised compared to the outside. Problably want to add a few degrees to the compound and correct to well inside the feed tubes starting point. I seem to have rambled And one day... I'm gonna finally get a job as a machinist! Hope that helps. Luck Not Bruce Mike3
Wow Thanks a bunch!! This really helps... exactly the kind of info I'm looking for. It will take me a bit of time to digest it all, but if you or anyone could try to answer a couple of questions that come to mind off the top of my head.... 1. How large should the magazine be... or maybe more to the point, how many rounds should it hold?? Assuming it will deplete 3 balls per shot (3 cannons per turrent) 2. Does the bearing have to be sealed or could I incorperate some type of o-ring to provide the seal? 3. Have there been issues with any part of these failing (blowing apart)?? If so what typically fails?? (Do I need to provide extra strength in any particular areas?) 4. I hear people talk about "close tolerance barrels" -- how close of a tolerance?? I found some off the shelf 304 stainless tubing that I would like to use for the barrels and risers that is 5/16 o.d. and advertised as .028 wall thickness. That would make the theroetical bore size .2565 -- is that too tight... too loose?? 5. Are the risers ever secured into the magazine with anything other than a press fit? Ok, now I'm rambling on..... I'll ask more once I digest what you have given me. Thanks again for the detail-- It really does help!!
1) It's typically just done by inches diameter, three and four inches being really popular, and 5 big enough that at the end, the empty magazine is robbing the shots of power. I have not seen a design that has multiple layers of bb's that I have seen working reliably, although I know of at least one person working on it. Should be possible... 2) Emphatically yes. Sealed bearings are necessary in the current designs. 3) A friend and I were working a design and used either 6-32 or 8-32 and these were yanked right out when fired. Not enough plastic to hold the pressure. And of course, you could argue we just didn't use enough screws. I chose 1/4-20 because my old 'gneis had a turrent with a stripped screw, and it turned out two 1/4-20's or thereabouts were holding it well enough not to be noticed until I did some work on them. PVC accumulators sometimes get brittle and rupture, are shot through and rupture, or if you use the wrong glue shoot the end cap off. Use the extra strength stuff 4) Bending the barrels is a pain. Let me repeat that... Bending close tolerance barrels is a major pain. The bend both wants to go out of round and reduce diameter. If you can do it in .006, and this is within the limits of the royal steel ball bearings... you might have a winner. You also need to check to see if it is welded or extruded tube. Welded has the bead inside the tube, and this will allow air around it. BDE had a run done by a machine shop, these are pretty much the defacto close tolerance barrels, unless you get inventive. I would advise you to get their barrels, and save yourself some agony. The BDE barrels are a good product and well worth the money in my opinion. They will certainly save you time. Telescoping brass tube can be one oversize, bent, then an extruded close tolerance barrel chamfered and then added/soldered on. These are a little less durable, but are used often out west with plastic sleeves and are a good alternative. Their technique may vary, but there used to be a lot of pictures of boats with brass torpedo tubes. DO NOT skimp on your barrel bender... the one from harbor freight should be a paperweight, nothing else! The Rigid one works okay... I use steel brake line... it's cheap and sloppy enough for my bends. 5) Could be. A stainless bolt turned and bored would make a good insert. You would probably then need to face the end that goes in the magazine, and install in the magazine for drilling the feed tube... add a setscrew to hold in place, and it's not really so bad compared to wanging the lip into a riser (I used a filler rod, tapered rod and a hammer), and mashing the thing into place (arbor press, spacer, and prayer). After all the work turning the mag it is kind of barbaric to resort to such brute force caveman techniques! Not elegant at all Luck Mike3
1) The magazine should be as large as you can fit in the ship, and have as many layers of ammunition as you can fit without pushing the top of the magazine above the deck. basically, measure what the distance is between the center of "A" turret and the center of "B" turret, and then subtract 1/4" to 1/2" for clearance, and that's the outside diameter you should use. And if you have the internal height (the Iowa class should, unless you screw up elsewhere) you should go with a double-layer ammo tray. BDE has done it, as have many cannon-builders in my club. I don't know how much ammo that is, but you always want as much as you can fit and enough CO2 to fire it all. 2) The bearing does not *have* to be sealed. Just keep in mind that if it isn't, you'll lose some of your air pressure and your guns won't be quite as gas-efficient. I personally don't care that much, I just use two cubic inches of air per barrel in the accumulator, and put in a monstrously giant CO2 bottle (or better yet, HPA, once I get a big enough ship!). The same thing applies to sealing the magazine, using tight-tolerance barrels, etc. You can take the finesse route, or you can take the brute force route. I have found that the brute force route takes more gas but gets payoffs in reliability. I'd rather have a gun that I never have to take apart and clean than one that takes less gas to fire. 3) In general, there are several areas that fail. The most famous and spectacular failure point is the accumulator. If one of these is too weak, it will, um, rapidly disassemble itself, with unpleasant results. Basically, use schedule 40 PVC and proper PVC glue, or sturdy metal accumulators with soldered metal endcaps or pinned PVC endcaps. The next failure point that I have seen is the bearing. Some people like to superglue the bearing to the magazine and valve body, and over time the superglue gets worn out by the shock of firing. When the superglue fails, the magazine detaches itself from the valve body, and the cannon no longer functions until it is repaired. Better designed rotation mechanisms that don't rely on brittle superglue can overcome this. The next failure point is the magazine wall. Whenever the cannon is fired, the rounds in the magazine feeds go flying out and, when nearly empty, they crash into the magazine wall. If the wall is brittle or not thick enough, it may break. This is quite rare, and if you are worried, running a few lengths of gas line or other squishy padding along the impact area will prevent it. Another failure point is the barrel. The bends of the barrels can get worn out over time, and the barrels can also get dented and jammed. I will go into further detail on this when I answer your next question. Another failure point is the buna-ball valve. Occasionally, a ball valve with poor tolerances or a very long rod can get stuck in the open position. This can be fixed by pulling the trigger again to force it open enough and hopefully jar it back into position. The last major failure point is gas connections. Any point where a gas line connects to something can become a failure point, either by leaking or by blowing off. This can be prevented by either pouring superglue over the leak (when the system is depressurized or, better yet, under vacuum to suck the glue in) or using "hats". Hats are designed to go over the top of a gas line and its fitting, and mash it down tight so it doesn't leak or blow off. 4) I hear people talk about "close tolerance barrels" as well. I don't recall the tolerances they mentioned, but .2565 sounds about right, I think. The basic idea is to reduce blow-by and thus increase the efficiency of the gun. I have found that these "tight tolerance barrels" are highly susceptible to dents and dings, and I take twisted pleasure in shooting other people's gun barrels when I'm too close to hit their hull. Personally, I prefer loose-tolerance barrels that are easier to work with. For example, when I use 7/32" cannons, I use 5/16" steel brake line for barrels. The 5/16" brake line is capable of passing 1/4" ball bearings before it is bent. After it is bent, it can only pass 7/32" but that is fine. The extra space around the balls make sure that no dent is enough to jam the cannon and prevent it from firing. The brake line wears out faster than stainless, but it still lasts for an average of 2 years before it needs replacing. I'm not sure but I think the next size up of steel brake line will be fine for 1/4" balls. 5) Many people use a press fit for their barrel risers, but I find that to be a crude and simpleminded solution. The top shipbuilders in my club use the flared ends from the brake line as barrel risers. They cut a 1" length off each end of a segment of brake line, which includes a flared end. They then hold it down with a riser plate, which is basically a length of aluminum with holes cut in it. Put the non-flared end through the riser plate, put the flared end on top of the breech, and screw the whole contraption down. Very neat, makes for easier access to the breech if you ever need to do maintenance, and looks very beefy too. For my current crop of cannons, I plan to use thick-wall brass risers and a brass riser plate soldered together. if you have any more questions, please don't hesitate to ask.
Wow this is all great stuff!! I do have a some more qustions so here goes: 1. Question on this buna ball contraption. What holds the ball reliably to the rod? It seems as if it would have a tendancy to pull out over time. I guess that there is only a light(???) spring pressure to bring it to the seat until the accumulater pressurises and makes it seal?? Should the rod extend all the way thru the ball with some type of self locking nut on it?? 2. As for magazine Diameter, I started planning for 4 inch, but does anyone think there is room for 5 inch in the Iowa?? I don't have plans yet so I can't really tell. I do want all 3 magazines the same size to reduce design/ programming/ machining/ build time. 3. What material do most people make the different components out of?? I'm sure there is some type of compromise between weight and as Mike3 said, pulling screws out, or as Kotori said, putting a nice "inspection window" in the side of the magazine. Should I use a stainless bearing??(They are a little pricey, but they won't corrode and increase the amount of force required to rotate the magazine. 4. In most of the photos I have seen, (which isn't very many) it looks like the angled hole that leads from the magazine to the breech is simply drilled, with no type of "lead" or "chamfer" or "funneling" (however you would want to put it). If a little were put there would anyone suspect that it would help by funneling balls into the hole or hinder by causing a ball jam? Thats enough for now.... I can only type for so long!! Thank a lot to both Kotori and Mike3.. and everyone else. I finally feel like I am getting somewhere!!! [8D] (And starting to think I need to learn to type better!!!)
1) The trick to sticking the ball on the rod is to thread the rod. You can either turn down the rod a bit and thread it with a #4-40, or you can leave it at 1/8" diameter and thread it with a #5-40. Either way, you then stick the buna ball in your lathe and drill partially (NOT all the way) into it. Then screw it on, and you're set. 2) I don't know if the Iowa has room for 5" magazines, either. What I DO know is that the Roma (a ship that is remarkably similar to the Iowa, despite being Italian) does have room for 5" turrets. So you're probably OK, but don't set your plans in stone until after you've gotten the plans and checked. Building all three cannons to the same design is an excellent idea. The only time you DON'T want to do that is when you've got doubles over triples, or some other weird combo like that. 3) For most of the cannon, I would recommend PVC. It's easy to machine and works quite well. For the stuff that will be under a lot of stress, use aluminum or brass. I prefer aluminum except when I am soldering, because aluminum is shinier than brass. Interestingly enough, you could probably make a significant chunk of the cannon out of wood if you have to. As long as it's downstream of the buna ball valve and is built beefy enough, you should have no problems. 4) There are actually several ways to do that section of the cannon. A lot of people simply turn their cannons at an angle and run a drill bit through. I have found that solution to be rather crude because the drill bit is rarely rigid enough and wanders. The more advanced cannons (including the cannons made by BDE) use a mill to cut a slot, rather than trying to drill the angle. If you're really clever, you can CNC the slot with a ball end mill. What BDE does is to cut a slot most of the way to the breech, then run a drill bit for the last little bit, using the slot to keep the drill bit from wandering. This works fine if you press-fit the barrel risers in. What I do is run the slot all the way down, and cover the breech area with a plate that holds the risers. It's not quite as good of a seal, but it still works and it's easier for me to do on a manual mill. I believe you'll be OK if you put some sort of lead, chamfer, or funneling. (we don't have a term for that yet, so you can choose whatever you like) What it will do is help guide balls to the breech when the magazine is almost empty. At that point, there will be too little ammo left to get jammed. Just keep it shallow and you should be A-OK.
I had to take a break from typing Elmer Fudd voice "ah wore my widdle feenguhs out" Carl has great points. Thanks Carl! It is great that people are sharing this info. on number 4, Carl's right on, drilling with a twist drill is problematic, And if you don't have adequate machine, center drilling, and using a brad point bit to start is not too bad. If you have a cheap drill press, the spindle play really can hurt you on lining up these holes... My 50 buck Northern Tool drill press was no bargain in the end. And losing position as you change drills and holes on a regular drill press table blows. A good compromise for those of you reading who don't have a mill is to get a good x/y table for about a hundred bucks. Best solution I haven't done yet is a ball end mill so there is no terrible overshoot intersecting the far end of the riser. Even if the magazine bottom is perfectly flat, then you will be relying on the ship rocking around to put balls in the feed tubes. If you have a large 5 inch magazine, and haven't adjusted sfpm across the face, it is likely belled down toward the od, as the excess heat/rubbing swelled the plastic high on cutting, leaving it low after cooling. This isn't a problem until you are running out of ammo, and then the extra capacity that the extra inch diameter got you is rolling around the outside of the mag, not dropping into the feed tubes. So, I would say channeling the bearings towards the feed tubes is a good idea. I've added channeling to two of my friends boats, and they fire just fine. Both those fellows have sunk me since... what gratitude I will say though that I am definitely interested in the air conservative techniques. I helped a fellow through getting his cannons from laughable results to 1 and 3/4 pen. It took every published and unpublished trick to do it too. luck M3
How tall do you guys think the entire rotating assy. can be without the accumulater or risers? It seems like my design is getting too tall as I add room for additonal components (mostly to provide an extra measure of saftey) and ease of manufacture. I am currently close to 2 inches tall, and I'm not done yet. I may be able to make it shorter, may HAVE to make it taller I don't have any experience to make an educated guess, and I don't know how much room there is in the hull. I don't want to dump another 5-6 hours into design if I need to make drastic changes to meet height restrictions. And yes, that's an excellent point on drilling the angled holes. I won't have any issues with it but others reading this thread might!!!
One advantage from Carls description of using material above the feed tube to complete the feed tube as an assembly is that the weight will help counter balance the weight of the barrels. If the outside (of three of four) risers are really close to magazine edge, the loss of ammo is not too bad. The old JCWhite design offset the manifold. The offset manifold makes rotating a pair of these guns interesting The other thing about Carls design is if it's easier to do manual, then I'll definitely like to look into it. Last time I went at it the magazine was a wee bit big for my machine and set up. Seems to me that you could always add a brass tube and fill the void with some type of filler if you wanted the original drilled effect. For some reason, the guns on my 'gneis built in 96 were this way. Luck M3
could someone explain how the ball bearings feed, like what the slope is that they transverse to get fired
CPT, have you seen the link at the top of the page that NooNoo posted? That shows the basic operation of the cannon.
how is everyone manufacturing their magasines are you just sending some plastic parts off to someone with a cnc or flow jet or is there a basic at home way to make them
Squires, contact the Australian Battle Group. I hear they have a local guy who makes all their cannons. Here in the US, we either buy cannons from BDE, or build them ourselves with lathe and mill.
