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Author Topic: Micro Mortar = 3mm  (Read 1074 times)

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Offline Cal.45

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Micro Mortar = 3mm
« on: July 22, 2009, 01:30:20 PM »
It's been some time, since the micro mortar was discussed about on this board but I just finished this one...



Please consider: I just got my lathe lately and I still need to learn much about using this tool efficiently...





The pictures above show the 3mm (3 millimeters = slightly over a 1/10th of an inch in projectile diameter) coehorn mortar besides a Caliber .45 coehorn.
Both should be as close to the drawings as I can get by now...

BTW: This is a great forum!
Jorg (from Germany)
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Offline RocklockI

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Re: Micro Mortar = 3mm
« Reply #1 on: July 22, 2009, 01:50:29 PM »
 :o wow Jorg thats great ! welcome to the board !

are they functional ?

gary
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Offline Double D

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Re: Micro Mortar = 3mm
« Reply #2 on: July 22, 2009, 02:14:32 PM »
According to Georges Round ball calculator that 3mm is a 0.0002 POUNDER.
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Offline Cal.45

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Re: Micro Mortar = 3mm
« Reply #3 on: July 22, 2009, 02:39:32 PM »
Yes, of course they are functional!
I need to build the mortar bed still (from wood) and find a way to manufacture the screws...
That's something to consider, since with such a small mortar the screws holding the bed together are EXTREMELY small!

BTW: The 3mm mortar has a powder chamber as well: it is 1.7mm in diameter...



You need to have a very fine granulation of BP to fill this thing...   ;D
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Offline dan610324

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Re: Micro Mortar = 3mm
« Reply #4 on: July 22, 2009, 02:56:47 PM »
what diameter is the touchhole ??
I suppose you cant use a 3 mm fuse  ;D

thats an extreme mortar

welcome here
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Offline RocklockI

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Re: Micro Mortar = 3mm
« Reply #5 on: July 22, 2009, 04:24:09 PM »
how about eye glasses replacment screws .

you got to show it in it's flaming glory !  ;D that could make next years calender .

back in my fly fishing days we had a saying (being that in the rockies most trout are smallish)

it went 'how small a fish can you catch and still be happy' ......for me PDS ! ;D .

those are very cool . i cant wait for it's fire and thimble sized cloud of smoke  :D sorry Jorg i couldnt help myself .....

have you ever shot a blank ? 4F?

hang around please as those are truly unique ! have you thought of making a quick match for it ?

gary
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"I've seen too much not to stay in touch , With a world full of love and luck, I got a big suspicion 'bout ammunition I never forget to duck" J.B.

Offline KABAR2

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Re: Micro Mortar = 3mm
« Reply #6 on: July 22, 2009, 04:59:37 PM »
I think 4F will be like forcing a boulder into the chamber....... he needs to collect the dust from the inside of a BP can!


Cal.45,

Very Fine work! do you repair Swiss watches on the side?

When I first saw the lathe turning I thought that's a very small Minnie Bullet. ::)


There are places that have micro nuts bolts & screws I will dig up the website for you.



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Offline KABAR2

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Re: Micro Mortar = 3mm
« Reply #7 on: July 22, 2009, 05:03:41 PM »
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Mr president I do not cling to either my gun or my Bible.... my gun is holstered on my side so I may carry my Bible and quote from it!

Sed tamen sal petrae LURO VOPO CAN UTRIET sulphuris; et sic facies tonituum et coruscationem si scias artficium

Offline Terry C.

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Re: Micro Mortar = 3mm
« Reply #8 on: July 22, 2009, 05:09:33 PM »
Micro?

Nope, too small.

Pico-mortar!

I refer you to my official unofficial scaling guidelines

Quote from: Terry C. on February 24, 2008, 04:53:41 PM
For the purpose of characterizing these small models, I humbly submit the following guidelines for the bore diameter of cannon and the chamber diameter of mortars:

Micro = bore of no more than firecracker caliber -or- chamber dia. of 1/4" or less

Nano = bore of no more than BB caliber -or- chamber dia. of 3/16" or less

Pico = bore of no more than 1/8" dia. -or- chamber dia. of 1/8" or less


I hope these are acceptable to all. If not, please offer any suggestions you may have.

Looks great, can't wait to see the mortar bed!

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Offline prospector86

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Re: Micro Mortar = 3mm
« Reply #9 on: July 23, 2009, 12:17:28 AM »
Looks pretty cool. What part of Germany are you in Jorg, I'm stationed in Schwienfurt, Bavaria
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Offline Cannoneer

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Re: Micro Mortar = 3mm
« Reply #10 on: July 23, 2009, 01:09:36 AM »
Jorg,

Just for kicks, why don't you send a photo of your mortar with specifications to Ripley's Believe It Or Not, and see what their response will be.
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Offline Cal.45

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Re: Micro Mortar = 3mm
« Reply #11 on: July 23, 2009, 12:41:59 PM »
Hello guys,
thanks very much for the warm welcome to the guild of BP mortar (and soon) cannon builders.

I have been watching this forum closely for some time, before I became member in 2005.
Until late this summer I didn't own a lathe, so my very first model of a mortar was done by using a drill press and some files. This one was caliber .177" (4.5mm) and out of scale in some dimensions, since I just had some bad pictures as reference back then. Later I bought the re-published drawings from Don and Jan Lutz of the civil war Coehorn mortar.
I really like the design of it: everything just fits.

My first model with the new lathe was the cal. .45 mortar you see on the 3rd picture besides the "pico-mortar".
(Actually I missed the topic, where you defined the "official unofficial scaling guidelines"...)
I tried to come closest to scale with my limited experiences on a lathe. But for a start, I think it's quite OK.

Now some background on the 3mm-mortar:
I bought the lathe with a display for the coordinates (no clue what the proper English term might be). By the time I finished the cal. .45 mortar I learned it to be a fine gadget. While I already did the BB-size model I wanted to see, if I could minimize it even further. In search for an easily available source for projectiles (I didn't consider casting for a single second), I noticed that within a shotgun shell there's plenty of them in quite uniform diameter...
The touchhole actually has two diameters: It is .5 of a millimeter all the way through (to retain some pressure ( ;D !) in the chamber) and on the outside it's 1mm for the fuze. That's the only detail on this thing that isn't in scale. I even used the 6 degree taper at the chamber area. The trunnion is also late turned and silver soldered in place.
Actually I need to make my own quick match for it: since even the smallest commercial fuzes are just to big for this thing. I'll be using a very fine granulation of BP used for priming flint-lock muzzle-loaders. It is basically dust. I'll post some pictures when I'm done with the mortar bed.

Thanks for the suggestions for the screws but the eye glasses replacement screws are much too big and I doubt that the micromark ones are in scale to this project. I guess I'll just make them by myself. BTW: I'm living between the city of Duesseldorf and the Dutch border.
I will post the drawings here soon but I doubt that I'll contact "Ripley's".

Best!
Jorg
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