My first two fabricated BP cannons: .30 and .50 miniature nontraditionals

[tiktock]

Hello!


I am a knifemaker from NH and I recently decided to fabricate two small black powder cannons.  I read some of the safety specs and tried to stay within them as I am a complete beginner in the cannon world.  I wanted to show the fruits of my labor and a bit of the process of each and ask what i could/should have done differently.  Both cannons function great!


Here are a few pics of my first one, a .30 caliber designed to shoot 5/16" ball bearings.



I began with a pretty solid hunk of steel.  Its nothing special as I've found mild steel is more than enough for these based on research.  I first cleaned up the block on my Bridgeport mill for squareness and sprayed it with layout fluid.  The block began with dimensions around 2.75"X1.5"X1.25":



Next I scribed some lines to keep things relatively straight.  I didn't go anal retentive on precision here as this is not as intricate as my folding knives but I am a bit OCD about certain things so its still pretty dead on.  I'll be shooting 5/16" ball bearing out of this (slingshot ammo) so I first drilled a starter hole a bit smaller.





Here it is all lined up.  What you dont see is i have the block angled about 5-10 degrees so that the fuse burns at an angle towards the front of the bore.  I let the fuse hole intersect the bore a few mm from the rear of the chamber:



Into my shop I went and bored the hole out to 5/16.  A 5/16 ball bearing is exactly .0312 while a 5/16 drill bit is .03125 although without going crazy with tolerances and care it usually leaves a hole a smidge bigger.  Here's the full 5/16 bore done:




Next I headed over to my little beast of a grinder.  It runs a 2"x72" belt off a 2HP motor and hogs steel as well as flesh pretty easily.  I've lost more skin to this badboy over the years than I care to mention.  I've paid it in blood and its paid me back.


I set the platen to somewhere around 45 degrees although i honestly just eyeballed everything from here out.


Initial bevels ground:



Once the bevels were in, i thought to myself "heck i may as well put some sights on this.  Obviously i really wont be aiming a smoothbore 2" barrel at much but hey, why not?  Good excuse to fire up the mill and make some chips.  I viced it up thew in a four flute 1/2" endmill:



Here it is after the first pass...mild steel is SO soft compared to the stuff I usually mill.



Here it is after a second pass, leaving a ridge in the back for the sight notch.  Looking good as far as I was concerned.  I left a nice rough finish as I knew i'd be cleaning it up on the grinder:



I put on a 220 belt and did some initial beveling of sharp edges, deburring etc.  I also counterbored the bore.  First time Ive actually used a counterbore on a bore.  Ironic!  As you can see, the steel heated a lot during grinding causing some surface rust in the bore.  No biggie as I planned to do a final reaming later.



The only part that couldn't be finished by machine was the space between the sights.  Ugh...I'm used to hand sanding so out came the block and paper.  I've developed a skill at mundane tasks knifemaking so this was easy:




Back to the mill to put in the rear notch.  1 minute later.  How do people get by without a mill?  Ugh i remember the days of hand tools only before I sold enough knives to begin buying tools.  Those days sucked:



Being an egomaniac, I had to put my name on this thing.  I etch my name by electricity.  The etcher uses basically a stencil much like a silkscreen stencil, an electrolyte solution and AC/DC current.  Here's the stencil in place:



And etched.  I didnt go too deep as it eats up the stencils and I save that for stuff I sell.  You'd still need to grind this off to remove it.  Now when this thing gets registered as a WMD, they'll know who made it:




And finally, a few shots in my hand.  What a cool little project.  I had fun, learned a bit and have a new toy to play with.

[tiktock]

And here are a set of pics of my second cannon:

First, I went around my shop and located a pretty hefty chunk of steel.  This hunk is an odd oblong shape with a diameter of about 2.5" wide by 1.75" high and the length of the usable steel is around 6"..perfect!





I then bandsawed off the scrap portion, squared up the ends on the mill and sprayed it with layout fluid:





Luckily, .50 is pretty easy to drill into steel with a milling machine so I drilled a bore about 4" deep:





This left 2" behind the bore.  I planned to do a 7/16" full-through trunnion and 2" allowed room for this while still maintaining a 1:1 between bore size and surrounding metal to keep things safe.


Here it is with a 1/8" fuse hole drilled at a 5 degree angle back and the 7/16" trunnion hole straight through:





Off it went to the 2X72" belt grinder.  The steel I was using was pretty pitted and dented so i started cleaning up the grinds:





I wanted nice, uninterrupted grind lines front to back like this:





Here is the last pic I took before moving to a finer finish but pretty much looks how it ended just before adding a bevel around the edges and final countersinking of the bore and holes:





Behind it you can see the norton blaze ceramic belts I use.  These things EAT steel.  They dont even pull off sparks as they cut so well they just throw a steady stream of metal filings downward. 



Unfortunately, things got late at this point and I gave up taking pics.  I'll describe what I did next:


I cut out some nice hunks of random hardwood I had laying down.  Some kind of rosewood for the sides that required me to pin them together with 1/4" stainless pins which I peened and epoxied in place.  I put oak burl for the endpieces.


After some fitting and measuring, I drilled holes that would allow the 7/16 trunnion bar to press-fit into the carriage sides.  I also drilled three elevation holes and fabricated a little bar which is held with removable pins to adjust for barrel elevation.


The entire thing is held with threaded rod and nuts which I plan to replace with acorn nuts.  It is a VERY sturdy little unit with an overall weight around 6 pounds.  It looks GREAT...even better than i expected.  It reminds me a bot of a mortar carriage with a modern barrel.


Here are a few pics of it completed:












Once I get a nice lathe, expect LOTS more from me.  These things are so fun to make.

[neros]

Congratulation on work well done.  The first one was of an unusual design, and I liked it a lot.  And the extra weight of the barel will be nice to have to absore recoil.. Cool to see the results of someone thinking "outside the box" 

[viper22]

That second cannon looks great. The carriage is giving me ideas for my .50


Scare the neighbors with it yet?