Author Topic: Beer can Mortar (Read 3810 times)

Powder keg · « **on:** February 16, 2005, 04:26:51 PM »

Hello All,
I started a couple of beer can mortars this week. They are bored out to 2.625". They have a 4.5" OD. and they are about 8" long. I started turning the profile using the incremental cut method. I've had great results with this. A useful book is Tables and Instructions for Ball and Radius Generation by Guy Lautard.http://www.lautard.com/ In the first picture you can see the setup for my indicators and on the right you can see the mister I use to keep everything cool.

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In the second picture you can see the steps created. I'll file and smooth them tomorrow.

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In the third picture you can see my new toolpost:O)

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Later, Powder Keg

Powder keg · « **Reply #1 on:** February 20, 2005, 01:12:16 PM »

Hello, I've been busy. In photo 1 you can see the two mortar's after I've filed and sanded and polished the radius on the end. The second photo is just a close up. The whole operation takes me about an hour and ten minutes. Also, I forgot to mention the material is 4340. Now I'm off to the mill to mill the round slot in the end for the trunnion. I'll post pictures of that as soon as possible.

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Cat Whisperer · « **Reply #2 on:** February 20, 2005, 02:05:40 PM »

Golly gee! I'm impressed Powder Keg!

I like your setup with the indicator to tell you the location of the cuts too!

Re: mist cooling - how do you like it? I assume it's to cool the center as well.

How do you like the 4340 compared to the 4140 or 4130? Looks like it turns a lot smoother.

THAT'S A LOT OF FILING!!!! Looks good too!

When the time comes, fill the cans with concrete. If you try sand or an agregate you'll find (as sometimes with concrete) the aluminum is so thin it opens up like a daisy about 20 feet in the air. The old cans were easier because you could remove the whole top easily.

Radius on from the spherical radius to the bottom band was well done too.

Powder keg · « **Reply #3 on:** February 20, 2005, 03:08:57 PM »

Hello Cat Wisperer,
Thanks! I've got a radius cutter in the works, but this works so good I haven't got around to finishing it. The total time filing was only about 20 min. For the other radius I have a tool I made that holds a 1/2" round carbide insert.
At work I hired a guy that turned me on to mist coolant. It never seemed like it would be worth it to me. But since then I love it. My lathe at home was made in the 30's and there was no practical way to add a flood coolant system. This was the ticket. It's very inexpensive and goes a long way. Plus I can use it on my mill.
I use 4340 because the place I work sells it to me cheaper than I can buy 1018. I haven't turned 4130 before but this is harder and more abrasive than 4130.
I can't wait to fire this sucker:O)

CU_Cannon · « **Reply #4 on:** February 20, 2005, 04:10:36 PM »

Good looking work. I tried the same method on my golf ball cannon. I got a little impatient so mine didn't turn out exactly round. There is always the next one.

I picked up Guy Lautard's The Machinists Bedside Reader a while back. It is a good book, well worth the price. There are a lot of great tips including the incremental cut method for cutting balls. At some point I'll order some of his other books.

Powder keg · « **Reply #5 on:** February 26, 2005, 02:06:06 PM »

Hi,
I had a chance to do some work today. In this picture you can see my fancy homemade angle iron vice and the beer can mortar with the trunnion grove milled in the breach. The boring bar is also homemade. It just has a hole cross drilled in it and the 1/4" carbide bit is held in with a setscrew.

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Cat Whisperer · « **Reply #6 on:** February 26, 2005, 03:51:20 PM »

Powder Keg -
Smooth lookin' cut! I value the home-made tooling as for a lot of us it's the only way the job will get done. Clamping setup looks rigid.

I'd love to have a double vee-block clamp (like a tumble jig) that would fit into the milling machine vice so I could cut two trunion pockets in perfect alignment with ease.

Powder keg · « **Reply #7 on:** February 26, 2005, 04:15:05 PM »

Hi,
Tumble jig? I assume it's a jig you clamp a part into and you can relocate or turn the part over on the mill without un-clamping it from the jig. Never thought of that. Interesting, very interesting. You use some heavy angle iron, weld some flat bar on to the bottom of the V to make some quickie V blocks. maybe have brass pads to protect the barrel? I milled the trunnion groove before the barrel was finished so clamping in the mill wouldn't maar the finish. If your welding the trunnions on you need to see the jig that Rick Neff from Neff Cannons built. If I make it over there I'll see if he would let me take a picture of it.

Cat Whisperer · « **Reply #8 on:** February 26, 2005, 05:11:07 PM »

That's exactly what a tumble jig is/does. Often made like a box jig and frequently will have drill bushings. I could see just a simple pair of vee-blocks that bolt together that would index onto a stop that's attached to the milling vice. Locate, drill, flip, drill.

Every picture we post here is going to provide an answer to SOMEONE's fixturing question.

Powder keg · « **Reply #9 on:** February 27, 2005, 02:59:48 PM »

Hello All,
I did some more work today. All I have left is everything else. Need to drill and counterbore for the trunnion and drill the vent. I decided to use one 3/8 cap screw to hold the trunnion on. I think this will work fine. I have some Hickory for the carriage.

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Cat Whisperer · « **Reply #10 on:** February 27, 2005, 03:22:49 PM »

Gettin' close to Lock and Load one Top Flight #1.

CU_Cannon · « **Reply #11 on:** February 27, 2005, 03:41:44 PM »

It looks great!

A beer can size mortar may be in my future. What are the dimensions of the powder chamber?

Powder keg · « **Reply #12 on:** February 27, 2005, 04:22:10 PM »

Hi, The powder chamber is 1" X 1.5" deep. It might be to small? I'll just have to see. Later,

GGaskill · « **Reply #13 on:** February 27, 2005, 04:25:44 PM »

about the size of the chamber in my beer can mortar. Much more powder causes the concrete in the cans to break up upon launch.

Powder keg · « **Reply #14 on:** February 27, 2005, 04:43:10 PM »

Looks like I'll need to start gathering up some ammo:o)

Double D · « **Reply #15 on:** February 27, 2005, 05:48:18 PM »

Powder keg.

That powder chamber is plenty big.

You need to keep a close eye on that 3/8 cap screw. It would be a lot safer to weld the trunion on, especially as shallow as it is. I don't know what the groove is for in your trunion. You need to be sure that the trunnion block supports the trunion on either side of that groove or the trunion will shear.

That thing is coming out pretty nice.

Powder keg · « **Reply #16 on:** February 27, 2005, 06:09:15 PM »

DD, I machined a grove in the end of the trunnion for a pin that is inserted into the carriage that keeps the cannon from moving from side to side. For the carriage I will use 1.5" X 4" thick Hickory "rails". I'll keep an eye on the cap screw. Thanks,

Cat Whisperer · « **Reply #17 on:** February 28, 2005, 04:07:14 PM »

I use 1/4-20 Allen SHCS's in mine - no problems. it's obvious if it loosens, and using an allen wrench you can get them very tight.

I did wonder what the groove was for. Makes sense now.

Powder keg · « **Reply #18 on:** February 28, 2005, 05:27:53 PM »

I built a little 1" bore mortar and it wouldn't stay centered in the carriage. I didn't want to have a visible "keeper" so this is what I came up with. I've just added it to all the mortars I build. I drilled the vent tonight. Sorry, no picture:o(

Double D · « **Reply #19 on:** February 28, 2005, 06:45:59 PM »

Groove makes sense if you have the type of base that allows that kind of movement.

Powder keg · « **Reply #20 on:** March 01, 2005, 03:39:43 PM »

Hello All,
Finished the machine work on these two Bad Boys. Now it's time for the finish. I've mainly used cold blue, but for this I'm thinking of a plum brown. I think it will look nice with the hickory I'm going to use for the carriage. I've found the cold bluing isn't very durable. What kind of finish does every body else use. Does anybody have any suggestions on applying plum brown? Can't hardly wait to do some shootin:o)

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GGaskill · « **Reply #21 on:** March 01, 2005, 03:43:26 PM »

on plain steel.

Powder keg · « **Reply #22 on:** March 01, 2005, 03:47:24 PM »

GGaskill, The steel is 4340. Was that a question?

GGaskill · « **Reply #23 on:** March 01, 2005, 03:52:18 PM »

No, part of the message was in the title block. But I see that is difficult to see with this software, so I guess I will stop putting text in the title unless I start a new thread.

Powder keg · « **Reply #24 on:** March 01, 2005, 04:01:14 PM »

Ok, I see it now. Black enamel paint on plain steel:o) I've used this before. I like to experement and try new methods. You'd be suprised how many mistakes you can make. I learn all kinds of stuff that way:o)

CU_Cannon · « **Reply #25 on:** March 01, 2005, 04:08:36 PM »

Has anyone tried rust blue on there mortars. I've thought about trying it on my current project. I was wondering if anyone had any experience with it.

I found a hot blue recipe that is simple but it involved the use of some nasty chemicals. IÂ’m not sure if itÂ’s worth the hazard.

Double D · « **Reply #26 on:** March 01, 2005, 04:10:30 PM »

I have here a set of full scale drawings for Confederate 24 PDR and 12 PDR Coehorn mortars. The notes say the tubes were painted with gloss black paint. The Mortar beds were made of southern pine due to the lack of seasoned white oak. The beds had linseed oil applied to them. Federal moartars as well as Federal and Confederate cannonon carriages were painted olive drab.

Evil Dog · « **Reply #27 on:** March 01, 2005, 04:17:38 PM »

Powder Keg..... Plum Brown works very well and to these old eyes is much more pleasing than any form of blue. It is also real easy to use. 2 things to remember though... completely degrease the barrel and heat it up until a drop of water will sizzle when dropped on it. I've found that plain ol' acetone works real well for degreasing and a hand held propane torch is adequate for heating. Once the barrel is hot enough you can liberally brush on the Plum Brown with whatever is handy. I've found that a piece of old sponge held in a twisted wire works pretty well. You probably won't be able to do the entire barrel in a single pass... just work in overlapping sections. Also it will probably take more than a single coat to get the desired color and coverage. Not sure just how healthful breathing the fumes is but it hasn't killed me yet. Rinse well with clean water on a rag between coats until you have the color you want then add some baking soda to the rinse water and wipe the whole thing down well. A finish coat of paste wax will also help... suppose you could use car wax although I prefer Johnsons Floor Wax.

Just take your time and it will work out well. A hickory carriage would be similar in color to my oak..... one of these days I might get around to browning the rest of the metal work on it.

Powder keg · « **Reply #28 on:** March 01, 2005, 04:24:00 PM »

Mabey I'll paint them? I don't know. But for some reason to me paint implys "cheap". I know it's more authentic, but I just spent an hour polishing and I don't like the idea of just painting them. Their so shiny the paint would probably just slide off anyway.

Cat Whisperer · « **Reply #29 on:** March 01, 2005, 04:27:41 PM »

Most everything I'm doing right now I leave in-the-white.

My first (beer can (1974 size)) was bright chrome plated - cost me $10 at the plating plant (those were hard times of the economy and I got a deal).

My second (4.55" for 4" pvc pipe (on the left in the aviatar)) was Armaloy (industrial hard-chrome) plated inside and out.

My third (16-20-24 oz soda pop) left natural. It rusted some, but not evenly (4140). It's only been bored and chambered and will get finished out to be a mountain howitzer some day.

Another 20 I have had CNC made of 4140 and parkerized - beautiful black, and a few blued (Birchwood-Casey - also beautiful but rusts quickly).

The last half dozen are still in-the-white and most yet to be fired. 4140 does clean up easily. If they get rusty, a wire brush in the electric drill cleans it right up.

There are some good bake-on gun finishes. I would seriously consider them.