Author Topic: Nano-mortar (Read 40947 times)

Terry C. · « **Reply #120 on:** March 02, 2008, 06:49:33 AM »

Oops!!!

I saw the copper-plated ball in the photo and thought it was a BB. It wasn't until I went back and re-read the post that I realized my mistake.

I totally missed the part about it being a ".22 rimfire" barrel and assumed this was an airgun barrel (based on my misidentification of the projectile). I have edited out my stoopidity.

Is the copper-plated lead ball a shotgun pellet?

Cat Whisperer · « **Reply #121 on:** March 01, 2008, 02:17:26 PM »

IMPRESSIVE!

What finish to go on it?

Terry C. · « **Reply #122 on:** March 01, 2008, 03:12:35 PM »

Last night I drilled the vent in my tube. It's 1/16" in diameter, with a small countersink at the top.

I plan to order some of the .042" fuse. For this test, I had some pieces of small green fuse that I pulled from old firecrackers. This would prove to be problematic.

When it came time for the test fire, the tube was twisted onto the modified shotgun cleaning rod that I use to clean the ¼-scale Napoleon. I loaded the gonne with 2.5 grains of GOEX FFFg, a #4 buckshot pellet loosely patched with greased (Bore Butter) tissue paper, and one of the firecracker fuses.

MISFIRE #1

The fuse burned down to the touch hole and went out.

Being alone, I decided to try to fire again rather than unload the piece. If anyone else had been there I would have immediately abandoned the test, neutralized the charge, and unloaded the gonne with compressed air.

I waited about five minutes, then while holding the gonne in a safe direction, drilled out the fuse with a 1/16" drill bit. I inserted another piece of fuse and prepared to fire.

MISFIRE #2

Same thing, the fuse would not burn past the top of the vent. Once again after waiting, the fuse was drilled out. This time no fuse was used, the vent was trickled full of the FFFg and ignition was via butane torch. If the gonne did not fire on this attempt, it would have been unloaded.

SMOKE AND FIRE!

I won't attempt to fire again until I get some proper fuse. The pieces of firecracker fuse are old and unsuitable for use, and will be discarded. I have some of the 1/16" fuse but it's actually too large for a 1/16" vent.

The chamber is, in my opinion, too small for a larger vent.

All that said, when I did get it to fire, it made a very satisfying 'crack' and I actually jumped a bit (I had almost given up and halfway expected it to misfire again).

seacoastartillery · « **Reply #123 on:** March 01, 2008, 04:16:38 PM »

Max, Maybe I'm not so old after all; I found a tube of BBs at MY local Walmart. Thanks for that tip.

Terry C., Mike thinks maybe you ought to wear gloves when you touch her off. I agree and say of all these popping up recently, yours alone, looks like it may have some recoil. A great looking piece it is.

Victor3, Elegant is a single word description that fits your gonne perfectly. No need to say more. Very nice job!

DD, George is correct, as usual, all you need beyond a file is a little vent drill. Do you have a self-tapping sheet metal screw, #4 or #6? If so, file the threads off and shorten the little drill feature to the desired diameter, glue the head to the end of a dowel, make one of those native "fire starter bows with bent branch and piece of cord" and drill your vent.

We finally got back on the nano-Rodman. Don't you just hate it when real work gets in the way of play-work? Photos tell the story:

When we left off, we needed trunnions next. Mike helped me out a little by making a little wooden fixture to align the drill and hold the tube with a tiny hole for a .055" drill to go thru to engage the vent. He even made the drill bushing adjustable by drilling the guide hole eccentric so you could get the trunnion pocket exactly on center by rotating the drill bushing and making a couple trial cuts on a bit of scrap rod.

With the .080" deep pockets to be drilled, dimple first with a regular drill and finish with a flat bottom drill on both sides. Place a tiny dab of Brownell's silver solder paste in the bottom of each pocket and put the tiny two diameter, trunnion/rimbase piece in each pocket and hold them in place with a piece of bent, 1/8",drill rod, V-spring. Heat the whole thing to a dull cherry red and let cool. We can't pull them out!

Apply torch!

A little clean-up with soap and water gets rid of the flux.

Now I had to decide if the elevation sockets were necessary. Of course they were! How? Drill and chisel or punch? PUNCH.....just has to be easier. It was. A concrete screw provided the punch material and a cheapie, diamond, flash-coated, needle file provided cutting power. The tiny rectangle, .030" X .048", with slightly rounded corners, worked great. That 1018 steel is soft and takes punch impressions very well. A sliver of sheet metal was the spacer and 9 pockets appeared after two practice pieces. Not perfect, but pretty good!

The punch.

The elevation sockets.

Pretty darn close to scale on the muzzle too. It looks larger than BB size, but it's not.

That 350 shot tube of BBs is just 3.20" long.

I guess that's about it for the tube. A casemate carriage comes next and we are going to keep it simple, Simple, simple, simple, simple, if possible!!

Regards,

Tracy and Mike

Victor3 · « **Reply #124 on:** March 01, 2008, 08:07:59 PM »

I thought I had posted this last night, but I guess I didn't click the post button.

Either that, or there's a CONSPIRACY

between Terry C. and the moderators (Maybe the oil companies or the Scientologists too, but I have no proof) to keep my completed handgonne from being posted first

Anyway, here it is. Metal is 6" long. Overall is 30.5". I suppose it's about 1/2 scale (?)

I tapped the last rear 3/8" of the socket (7/16 - 20) so I could screw the tiller into it. Nice solid joint without having to use a crosspin.

I put a 30 degree lead into the muzzle to help start the projectile into the rifling.

Here it is with the finish - The wood is either birch or beech, which is a "beech" to get to take stain well. I used a brown analine dye instead. Still needs a few more coats of Tru-Oil. Steel was cold blued with Oxpho-Blue.

Looking forward to seeing how yours comes out Terry C.

EDIT - Oops. Now I can see several more posts, including yours Terry. Looks Great! Something going on on my end that didn't let me see everything recent for some reason

Victor3 · « **Reply #125 on:** March 01, 2008, 08:54:35 PM »

Quote from: Terry C. on March 02, 2008, 06:49:33 AM

Oops!!!

I saw the copper-plated ball in the photo and thought it was a BB. It wasn't until I went back and re-read the post that I realized my mistake.

I totally missed the part about it being a ".22 rimfire" barrel and assumed this was an airgun barrel (based on my misidentification of the projectile). I have edited out my stoopidity.

Is the copper-plated lead ball a shotgun pellet?

Terry,

The plated ball is made for 22 cal airguns. They are made by H&N in Germany.

By the way - I know you said that you have a lifetime supply of #4 buck, but if you find the need for something a bit larger and more consistant in diameter and roundness, Hornady's #3 is .250 +/- .001. You might not need a patch if you use it in your gonne. Many use it in their 25 cal airguns. In fact, I had first thought of using a piece of a Beeman 25 cal airgun bbl I have and Hornady shot (I have a lot of it) before I happened upon my old chunk of rimfire bbl.

http://www.cabelas.com/prod-1/0003199213690a.shtml

Victor3 · « **Reply #126 on:** March 01, 2008, 10:17:04 PM »

Seacoast,

You guys really know how to make us amatures feel bad

Your gun is obviously going to be quite a mini-showpiece there.

I appreciate your reviving this thread. I would never have attempted to make a mini-gonne without reading it.

This was the first gun of any kind I've made where I didn't have to buy a single tool or piece of material. Only took about 12 hrs to make also.

Thanks everyone else too - This is really fun stuff. Can't wait to shoot mine...

Terry C. · « **Reply #127 on:** March 02, 2008, 06:13:21 AM »

Tracy & Mike, you guys have outdone yourselves! Looking forward to seeing the mount.

I fitted a tiller to my gonne this morning. It's made from a 7/16" poplar dowel, reduced to 3/8" on the socket end. Straight and smooth but very little grain showing. I wanted to use oak but Lowes didn't have any oak dowels in 7/16" and the few that I did find at another store were so badly warped that I couldn't use them. If I do find a good straight 7/16" oak dowel with nice grain before I put a lot of work into this one, I will switch.

The tube is 4" long, with the tiller attached the gonne is 28" overall. Right now it's just a very tight friction-fit. I'm going to sleep on the subject of a retaining screw before I break out the drill.

There are some swirl marks that I need to polish out before bluing, where the tube transitions from tapered to straight. I was using the 3M RoLoc pads and put on a fresh pad to blend this area. The more aggressive cutting of the new pad does not match up with the rest of the finish. This only really shows badly in photographs, but I want to get it as even as possible before bluing.

This is as far as I'm going with it this weekend, the rest of the day is pretty much booked up.

lance · « **Reply #128 on:** March 02, 2008, 01:33:51 PM »

Been offline a couple weeks, Just wanted to say that i really like everyones "nano" projects,much more than mine. Oh well, think i only spent about 20 minutes on the #12 "pico-gonne"........wish now i would have dressed it up a bit. Just to show i'm still alive here's a picture of me and some cool small scale Dictator Mortars. Found them at a cemetery on a trip down to North Carolina yesterday.

seacoastartillery · « **Reply #129 on:** March 02, 2008, 04:12:12 PM »

Lance, We are glad to see you are back. The imagination shown by your "pico-gonne" more than makes up for lack of spit and polish!! AND, it functions as well! Those small Dictators are very unusual. I don't believe we have ever seen anything like them anywhere.

Regards,

Mike and Tracy

KABAR2 · « **Reply #130 on:** March 02, 2008, 04:45:51 PM »

Lance are those mortars carved stone?

lance · « **Reply #131 on:** March 02, 2008, 05:05:24 PM »

Thanks Mike and Tracy, i figured you'd like them mortars............. Allen"Kabar2" sad to say they are carved stone, Thats the Maine monument, there are others there. Some of us went on our annual Salisbury N.C. Relic Show Trip. Had to stop by the Confederate Prison and Cemetery. Supposed to be 11,700 Union Soldiers buried in 18 ditches a few feet from where i'm sitting. Those mortars were carved in 1909 if my memory is correct.

Victor3 · « **Reply #132 on:** March 02, 2008, 08:03:48 PM »

Did test firing today.

My Son thought it would be fun to use a...well, let's just say 'unusual' form of shot that he found in the yard...

Seems to be of correct caliber when closed up...

Powder scoop for the FFFFG Goex; A 22 CB cap case glued to a stick...

Here's my helpful 1/2 scale 'genetic experiment' showing how to hold a 1/2 scale experimental handgonne...

We took a couple of pics firing, but the smoke couldn't be seen against the light colored wall. There wasn't much in the way of smoke & fire with the tiny charge. I think I could go with a full-size 22 shell full with no problem.

Double D · « **Reply #133 on:** March 03, 2008, 03:44:15 AM »

So, tell me did it take a lot of talking to the kid to get him todo the test fire for you? Bet not. Funny, first time I fired my .404 Barnes Express, my kid said that's alright you can go first...course he was 30 something then and familier with the results of some of my projects back then.

Terry C. · « **Reply #134 on:** March 03, 2008, 04:57:31 PM »

Quote

There wasn't much in the way of smoke & fire with the tiny charge.

You might be surprised. The trick to getting good fireball photos is capturing frames from video. I've tried to get still photos of my guns firing and I've found it (at least for me) impossible. The visible fireball exists for a fraction of a second and then it's gone.

The jet of flame in this photo is from a 2.5 grain charge, probably about the same amount as your scoop. It only appears in a single frame.

As for your 'alternate' ammo, I've got some of those in my yard that might be more suitable for the golfball mortar...

lance · « **Reply #135 on:** March 06, 2008, 02:54:25 PM »

These NANO projects are fun to make!!!! I can find time to do them,but not the bigger projects that are stacking up. Anyway, here's another............Both the Union and Confederate troops used WOODEN MORTARS with iron bands, this one is BB size........alot easier to pour powder in than the #12 shot size Pico-Gonne, plus i don't have to crush the FFFG Goex either! Really, this wooden mortar didn't need the bands, but looks better with them. I've fired it enough tonight to know that the wood has not cracked or caught on fire, course i'm just shooting BB's. These little fun guns "among other things" will be at the next Floyd County Mortar and Cannon Shoot, when ever that is...........2 pictures of wooden mortar:

seacoastartillery · « **Reply #136 on:** March 06, 2008, 06:22:13 PM »

Lance, Mike and I thought you had used up your last great idea with the pico-gonne. Guess not!! She looks like a very sturdy shell thrower, ready for some Vicksburg-style action. Is the wood Black Gum, Nyssa Sylvatica, also called Tupelo, by any chance? ANOTHER, remarkably creative, entry from Lance! Who's holding back? Josco, have you decided what your nano-mortar or cannon will be modeled after?
The nano-Rodman casemate carriage will be finished up Saturday. Test firing of the tube was a success.

Until Saturday evening we remain,

Mike and Tracy

Cat Whisperer · « **Reply #137 on:** March 07, 2008, 12:51:11 AM »

Hmmm.

Nope.

I'll start a new thread.

lance · « **Reply #138 on:** March 07, 2008, 02:42:03 PM »

Thanks Mike and Tracy, I have plenty of ideals,but not enough hours in the day! Didn't use Black Gum,seems to be a shortage of it in these Virginia mountains. Looking forward to the RODMAN pics!!!!

Victor3 · « **Reply #139 on:** March 07, 2008, 10:53:03 PM »

Quote from: Double D on March 03, 2008, 03:44:15 AM

So, tell me did it take a lot of talking to the kid to get him todo the test fire for you? Bet not. Funny, first time I fired my .404 Barnes Express, my kid said that's alright you can go first...course he was 30 something then and familier with the results of some of my projects back then.

Hehehe...

I took the first shot. Believe me, my Son's no dummy either - he got a good dose of 'don't trust pops' when I got him to believe that Tobasco sauce was just the same as ketchup once. One of our main sources of fun with eachother is "Go ahead Son/Dad, it won't hurt a bit!"

I'm glad you guys are making more of these. High fun payoff for little time spent. I'm thinking of another now.

Anyone have a source of good small diameter (<.06" dia) fuse? I only have a little left.

Terry C. · « **Reply #140 on:** March 08, 2008, 02:23:12 AM »

I just received a package of fuse in the mail yesterday. I'd planned to post a review when I got a chance to burn a few pieces.

This is the 1mm Cross-Match Visco (5th item down on this page) from Skylighter.com.

This fuse is nice and stiff and very thin. I measured a piece with my caliper and it averages about .045". It fits loosely in a 1/16" diameter vent. It has a burn rate of 5 sec/inch so a little will go a long way.

The main downside so far is the cost. I've been buying fuse from CannonFuse.com, and their prices are much lower. In addition, Skylighter has a $30 minimum order (not hard to fill at the prices they charge).

But if you wanna play, you gotta pay...

I bought two 50' packs, a little over $40 with shipping. That'll probably be a lifetime supply.

I'll post more when I get a chance to do some test burns.

seacoastartillery · « **Reply #141 on:** March 08, 2008, 08:19:28 AM »

Terry C. Do these two packages look familiar? Yes, the cost is a bit steep, but you simply can't stuff a 1/16" piece of fuse into a .055" vent! This Skylighter, .045" dia. fuse's flame is wimpy compared to the 1/16" stuff from CannonFuse, Inc. which is EXTREMELY HOT burning. However, it fired a little 3.0 gr. chg. in our nano Rodman tube 3 for 3. AND.... it's very easy to light, unlike some 1/8" stuff we have used.

Regards,

Tracy and Mike

Terry C. · « **Reply #142 on:** March 08, 2008, 09:43:58 AM »

Yep, that's the stuff.

I just got through doing some test burns with the new fuse. You're right that it burns with less fire than the so-called 1/16" fuse (it's bigger than 1/16") and it also burns a lot slower.

Quote

you simply can't stuff a 1/16" piece of fuse into a .055" vent!

You can't even stuff it down a 1/16" vent! At least not without a squeaky-clean vent, a long taper cut on the end of the fuse, some generous twistin', and a whole lotta cussin'! And even then you can only get it to go in part way (but usually enough to get ignition). They shouldn't call it 1/16" fuse unless it will actually fit in a 1/16" vent. They should call it 5/64" fuse, but I guess that would confuse their clientele.

Okay, I feel better now...

Of the three pieces I tested (standard American Visco, premium 1/16" Chinese, and 1mm Cross-Match), the 1/16" was the fastest burning, with the standard A.V. a close second, and the 1mm by far the slowest. For size reference, these fuses are cut 2" long:

I made a a couple of videos of my testing. The first test was the comparison of burn rates, with the three pieces of fuse taped to the concrete step in front of our door. First up is the standard, then the 1/16", and finally the 1mm:

Vid 1

In the second test, I used only the 1mm fuse and placed a pinch of powder underneath the masking tape. I repeated this test several times and the powder never failed to ignite.

Vid 2

I have my micro-gonne broken down for a modification (more on that later) so no test firing with the new fuse yet.

The fuse does fit nicely into the 1/16" vent of the gonne:

And also the 1/16" vent of the Pullen micro-mortar:

The fuse in the photos is one of the 2" pieces I cut for testing. Due to the slow burn rate, this is way more fuse (about 8 seconds) than you'd generally want or need.

Terry C. · « **Reply #143 on:** March 08, 2008, 10:21:15 AM »

I almost forgot, there was another test that I ran which I didn't film. I did it sort of as an afterthought, but it was inspired by actual events.

I clamped a piece of the tiny 1mm fuse in a hemostat and locked it in its tightest position. I could feel the fuse crushing under the pressure.

I was trying to see if I could 'choke off' the flame. I repeated this test three times and the fuse burned through the restriction every time.

I'm satisfied that the fuse would be reliable.

As for the cost, it really isn't that expensive in the grand scheme of things. It's just that I've been spoiled by cheap fuse.

This on the other hand is a specialty item and as such the expense is justified, especially considering that this will probably be a one-time purchase.

The larger fuse gets used in greater quantity due to their much faster burn rates. With this fuse, you will only need about half as much to get an equal time delay.

Videos are uploaded now, links added to the previous post.

seacoastartillery · « **Reply #144 on:** March 08, 2008, 05:24:52 PM »

We managed to squeeze in a couple hours fun time in an otherwise hectic Saturday. The casemate carriage for the nano-Rodman is done! Far from fancy, but it will do to hold the tube steady in the upcoming Rocky Mountain Nano-Cannon Long Range Armor Penetration Tests of 2008. 1/8" Basswood at 3 feet? Why not. Photos tell the story.

After laying out the outline and location of the trunnion cradle and two spacer rod holes, I drilled these holes.

Hacksawing about 1/16" outside the lines was straightforward, moving the clamps as necessary.

The double cut smooth file was used to get the cheek edges down to the lines. 180, 240, and 320 wet and dry sandpaper came next.

The spacer pins were put in place with a small 1/2 drop of silver solder and the whole thing heated until dull red. Fixtures or clamps don't work here, because they are heat-sinks. If you don't bump the assy. as you heat it, it should NOT fall apart. The pins are .002" to .003" smaller than the holes to allow solder migration.

320 grit sanding of all surfaces comes next and then degrease with isopropyl alcohol. A little 44-40 gun blue and some gun oil completes the job.

A better view.

We are looking forward to shooting this beast!

Regards,

Tracy and Mike

lance · « **Reply #145 on:** March 08, 2008, 05:48:59 PM »

Mike and Tracy, the Rodman is SUPER COOL!!!! I can't hardly wait for the armor test results, i wouldn't mind holding a basswood pie plate at 3 feet

Terry C. · « **Reply #146 on:** March 08, 2008, 07:15:55 PM »

Really cool! looking forward to some smoke & fire pics!

The aforementioned mod to my micro-gonne is done. I'd been pondering how to secure the tiller, I didn't really want to drill a screw hole in the socket.

What I did, since I had some extra space between the socket and the chamber, was to add about 5/16" of #10x24 threads at the bottom of the socket. A short piece of SS threaded rod is glued into the end of the tiller and threads into the gonne. This secures the tiller without any changes to the external appearance.

(note: not to scale)

Once the mod was done, I blued the steel, oiled the wood, and assembled the gonne. I'll post a photo tomorrow when I've got good light.

I still plan to ditch the poplar tiller for oak when I find a piece that I like. This mod will make swapping tillers easy.

Victor3 · « **Reply #147 on:** March 08, 2008, 08:16:56 PM »

Quote from: Terry C. on March 08, 2008, 10:21:15 AM

I almost forgot, there was another test that I ran which I didn't film. I did it sort of as an afterthought, but it was inspired by actual events.

I clamped a piece of the tiny 1mm fuse in a hemostat and locked it in its tightest position. I could feel the fuse crushing under the pressure.

I was trying to see if I could 'choke off' the flame. I repeated this test three times and the fuse burned through the restriction every time.

I'm satisfied that the fuse would be reliable.

As for the cost, it really isn't that expensive in the grand scheme of things. It's just that I've been spoiled by cheap fuse.

This on the other hand is a specialty item and as such the expense is justified, especially considering that this will probably be a one-time purchase.

The larger fuse gets used in greater quantity due to their much faster burn rates. With this fuse, you will only need about half as much to get an equal time delay.

Videos are uploaded now, links added to the previous post.

Thanks for doing the tests, Terry.

Your testing method is similar to mine. I use needle-nose pliers. I guess I'll have to break down and buy some of that 1mm fuse too. I wish I could find some more of the stuff I have now. It's .05" dia and burns hot. I only have about a foot of it left.

Seacoast,

Great job on your Rodman. I'm thinking my next micro gun will be a 22 cal Parrott since I have another chunk of 22 rimfire bbl to use.

Tomorrow my Wife, Son and I will be going out to the desert to do a school science fair project involving a 1" bore Coehorn. We'll be measuring how far a lead ball goes at different charge weights and bbl elevations. Much more fun than the usual earthworm and butterfly presentations...

I'll be bringing the 22 cal handgonne along to see if we can actually hit anything with it.

Terry C. · « **Reply #148 on:** March 09, 2008, 09:21:47 AM »

Quote from: Victor3 on March 08, 2008, 08:16:56 PM

Your testing method is similar to mine. I use needle-nose pliers. I guess I'll have to break down and buy some of that 1mm fuse too. I wish I could find some more of the stuff I have now. It's .05" dia and burns hot. I only have about a foot of it left.

I had about a dozen pieces of thin green fuse that I'd pulled from old firecrackers, that I planned to use with the micro-gonne. It would burn down to the vent and go out. I made several attempts but never could get it to burn into the vent. I guess it was just too old, I threw the rest of it out and ordered the 1mm fuse the next day.

The frustrating part is that I have yet to fire the gonne with the new fuse. All of my successful firing was done with no fuse, just a trickle of powder down the vent and fire from my butane torch.

I broke it down to drill & tap for the hidden tiller screw, then polished and blued the tube, then oiled the wood. I finally got it reassembled late last night. I've been in and out all day, and I have to leave again in a little while. If it's not too dark when I get home this afternoon, I may pop off a couple of shots.

Quote from: Victor3 on March 08, 2008, 08:16:56 PM

Tomorrow my Wife, Son and I will be going out to the desert to do a school science fair project involving a 1" bore Coehorn. We'll be measuring how far a lead ball goes at different charge weights and bbl elevations. Much more fun than the usual earthworm and butterfly presentations...

Sounds good, if you can pull it off. I was approached with a similar idea by a student not long ago. The school officials' response to the idea was downright threatening.

It seems that our school board considers any organized gathering of students anywhere the same as school grounds and that if I brought any of my 'devices' (even without powder or fuse) anywhere near them I would be treated the same as if I'd brought a loaded gun onto campus.

What a world we live in...

lance · « **Reply #149 on:** March 09, 2008, 09:48:32 AM »

TerryC, i appreciate the videos of fuse testing and want to say you have me sold! Also have to say that your Gonne has the nicest lines and look of any i've seen.