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Author Topic: Nano Mortar  (Read 710 times)

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Offline jamesbeat

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Nano Mortar
« on: September 06, 2011, 07:11:06 AM »
I mentioned my nano mortar on another thread, so I thought I should post some photos of it:









Sorry about the blurry second photo, I was trying to shine a flashlight down the bore.


It's BB caliber, with a reduced diameter powder chamber to comply with the 1/3 rule.

It was made from a steel bolt shank, using only a cordless drill, files, and sandpaper. Took about an hour.
I have yet to make a carriage, and I'm also going to either brown or rust blue the barrel.

I haven't drilled the touch hole yet, so I haven't tried firing it. I really must get around to buying a tiny drill bit...
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He reached out and stroked shiny barrel. "Manuel, once there was a man who held a political make-work job like so many here in this Directorate, shining brass cannon around a courthouse."

   "Why would courthouse have cannon?"

   "Never mind. He did this for years. It fed him and let him save a bit, but he was not getting ahead in the world. So one day he quit his job, drew out his savings, bought a brass cannon--and went into business for himself."

The Moon is a Harsh Mistress by Robert A. Heinlein

Offline DukeInMaine

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Re: Nano Mortar
« Reply #1 on: September 06, 2011, 08:39:39 AM »
And what kind of tiny fuse will you try to insert in the touch hole?

Or, would you merely pour a small amount on a recess at the top of the touch hole, and hope that it goes?

It's kind of neat, I would say.
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Offline jamesbeat

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Re: Nano Mortar
« Reply #2 on: September 06, 2011, 08:52:37 AM »
I honestly don't know, I was planning on asking on this forum when the time came to drill the hole :D
I think I read something about 1mm fuse on the other nano cannon thread, so maybe a 1.2mm hole?

You'll have to forgive my metric measurements, I'm from England.
I've lived in the States for a couple of years now, but I still have trouble thinking in fractional inches.

Whatever size I need, I do know that it's going to have to be very small!
Of course, I'll have accomplished my goal if the thing even manages to go 'poof' and launch a BB, I'm not expecting enormous power and tackdriving accuracy :D
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He reached out and stroked shiny barrel. "Manuel, once there was a man who held a political make-work job like so many here in this Directorate, shining brass cannon around a courthouse."

   "Why would courthouse have cannon?"

   "Never mind. He did this for years. It fed him and let him save a bit, but he was not getting ahead in the world. So one day he quit his job, drew out his savings, bought a brass cannon--and went into business for himself."

The Moon is a Harsh Mistress by Robert A. Heinlein

Offline armorer77

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Re: Nano Mortar
« Reply #3 on: September 06, 2011, 09:15:32 AM »
Having made a similar size mortar use 1/16" or 1mm drill . It will work , but you need 3 or 4 Fg powder . Ed
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Offline Microboomer

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Re: Nano Mortar
« Reply #4 on: September 06, 2011, 10:49:30 AM »
Nice little Mortar!
Ignition is tricky with the little beasties - It's hard to make the vent small enough so you don't lose too much energy out the vent.   I've given up on fuses and am using 3F down the vent, and light with a small propane torch.  I tested a micro mortar drilled with a #55 drill (just over 1.3mm) with a small countersink to hold powder, and it ignites very reliably this way.  I'd try the 1.2mm drill and see how it works!
Search for "1:28 9" Dahlgren" and you'll find that Jeff had trouble getting ignition with a vent that was close to 1mm.  Mike and Tracy found a clever way around that though - search "nano cannon ignition" (w/o quotes) and you can see how they got around the problem.  I haven't tried it yet, but I will as soon as I get around to it.
I'm looking forward to smoke and flame pix!
andy
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Offline jamesbeat

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Re: Nano Mortar
« Reply #5 on: September 07, 2011, 05:04:23 AM »
Hmm, I did think I'd just be able to use a small fuse, but I see now that it may not be as simple as that.

I think what I'll do is drill the hole at just over 1mm, and try the brush bristle technique.
If that doesn't work, I'll try the countersink and torch method, and if that doesn't work, I'll enlarge the touch hole and try finer powder.
I'm reluctant to drill the hole at 1/16" (1.6mm) without trying a smaller one first, because you can't drill a hole smaller :D

I wonder if some type of electronic ignition would work?
I could probably rig up something with a nichrome wire element, or maybe even the piezoelectric sparker from a lighter (will this ignite black powder?)
Would electronic ignition be legal, or is it too 'modern' to comply with the law?
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He reached out and stroked shiny barrel. "Manuel, once there was a man who held a political make-work job like so many here in this Directorate, shining brass cannon around a courthouse."

   "Why would courthouse have cannon?"

   "Never mind. He did this for years. It fed him and let him save a bit, but he was not getting ahead in the world. So one day he quit his job, drew out his savings, bought a brass cannon--and went into business for himself."

The Moon is a Harsh Mistress by Robert A. Heinlein

Offline Mike Scott

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Re: Nano Mortar
« Reply #6 on: September 07, 2011, 06:39:54 AM »
A broom straw coated with 4f makes a good small diameter fuse.  I have used a glue stick.  Others prefer a spray adhesive.

Check this older post

http://www.gboreloaded.com/forums/index.php/topic,234670.0.html
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Offline Cannoneer

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Re: Nano Mortar
« Reply #7 on: September 07, 2011, 07:12:17 AM »
Quote from: jamesbeat on September 07, 2011, 05:04:23 AM

Would electronic ignition be legal, or is it too 'modern' to comply with the law?

I know we're not supposed to give opinions on what's "legal or illegal" concerning the subject of our board, and I think it's a good rule BTW; but if what you're going to fire is legal to fire in the first place, then I'd guess that it would be okay to fire it by electronic ignition.
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RIP John. While on vacation July 4th 2013 in northern Wisconsin, he was ATVing with family and pulled ahead of everyone and took off at break-neck speed without a helmet. He lost control.....hit a tree....and the tree won.  He died instantly.

The one thing that you can almost always rely on research leading to, is more research.

Offline Double D

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Re: Nano Mortar
« Reply #8 on: September 07, 2011, 07:48:20 AM »
Electric ignition is pre 1899....
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Offline Cannoneer

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Re: Nano Mortar
« Reply #9 on: September 07, 2011, 08:25:29 AM »
Douglas,
I knew you were going to respond, I just knew it! :D

I believe Ben Franklin was working on something in this area pre 1899. It's vague in my mind though, maybe something to do with igniting a British 3-pounder with a wire attached to something in the air, I cant quite recall the exact details. Just funnin', just funnin', now don't get excited and zap me!  :) ;D :D -  ;)
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RIP John. While on vacation July 4th 2013 in northern Wisconsin, he was ATVing with family and pulled ahead of everyone and took off at break-neck speed without a helmet. He lost control.....hit a tree....and the tree won.  He died instantly.

The one thing that you can almost always rely on research leading to, is more research.

Offline Double D

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Re: Nano Mortar
« Reply #10 on: September 07, 2011, 08:53:12 AM »
Quote from: Cannoneer on September 07, 2011, 08:25:29 AM
Just funnin', just funnin', now don't get excited and zap me!  :) ;D :D -  ;)

Zap you, oh groan, bad pun...okay funny pun.
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