Flat Horn Flask Project

[CEvonk]

I got the pilot hole for the spout drilled today.

First, I mapped the inside of the horn with a paper template that I made by tracing the outline of the horn onto paper, then cutting it to fit roughly into the horn. Little by little, I fit it into the horn, noted where the paper was binding, then trimmed the paper to fit the template a little farther into the horn. After a little while, I had a template of the inside of the horn. Ridges on the inside of the horn allowed provided a groove along which I indexed the paper as I was adjusting its size.

When the template was finished, I was able to lay it on the outside of the horn to locate exactly the end of the internal cavity to check whether my hole would be in the right place internally if I drilled straight in from the center of the end of the horn. As best I could tell, the hole and the tip of the cavity would line up.

I had already used blue painter's tape to mark the position of the horn spout as that would give me a visual reference in one axis as I drilled. Having the horn sawn perpendicular to the sectional axis at the end of the horn gave me a flat surface to gauge a 90 degree angle between the surface and the drill. The combination of these visual guides made it possible to drill pretty straight into the end of the horn cavity.

Inside the horn, the hole broke through about 1/16" off center from the tip of the horn cavity. The hole I drilled is straight in relative to the cut surface, but the tip of the horn cavity is not exactly aligned with the center of the horn, although it is close, and it is slightly oval in shape. The hole appears to have come through about a drill bit's width (3/32") off center on the inside, which is not really important, especially once I widen the hole to 1/4" for the spout.

Since the hole is perpendicular to the cut end, as the pilot bit in the hole saw follows it, the resulting spout will also be perpendicular to the cut end, which means it won't be pointing wonky, theoretically.

 

[CEvonk]

I was looking at the interior of the horn, thinking about how to trim the interior ridges so as to smooth the inside, and I had a thought. I'm going to heat and flatten the horn. I wanted to smooth the ridges down so that they did not interfere with the process by changing the flexibility of the horn in the areas where they run. The ridge height easily doubles the horn thickness in some places. Doubling the thickness of a material increases its resistance to compression loading by 4X. That means that the horn will be more resistant to bending, i.e. flattening, in the areas where there are internal ridges.

In this picture two of the most visible ridges at the end of the horn are marked "top" and "bottom." This orientation is the direction I need to squeeze the horn to flatten it out so that the spout points along the wide axis of the flattened horn so it can stand upright on the base, and not over the short axis which would make the horn tip over.

So, if I leave ridges in the areas that I don't want to flex (top and bottom -- flat sides) and smooth out the ridges on the thin, round edges of the flask, maybe the flask will be easier to deform in a controlled manner. I think it's an experiment worth trying. I can remove some ridges now, and some after the flask hardens and dries.

 

[WALT53]

I was looking at the interior of the horn, thinking about how to trim the interior ridges so as to smooth the inside, and I had a thought. I'm going to heat and flatten the horn. I wanted to smooth the ridges down so that they did not interfere with the process by changing the flexibility of the horn in the areas where they run. The ridge height easily doubles the horn thickness in some places. Doubling the thickness of a material increases its resistance to compression loading by 4X. That means that the horn will be more resistant to bending, i.e. flattening, in the areas where there are internal ridges.

In this picture two of the most visible ridges at the end of the horn are marked "top" and "bottom." This orientation is the direction I need to squeeze the horn to flatten it out so that the spout points along the wide axis of the flattened horn so it can stand upright on the base, and not over the short axis which would make the horn tip over.

So, if I leave ridges in the areas that I don't want to flex (top and bottom -- flat sides) and smooth out the ridges on the thin, round edges of the flask, maybe the flask will be easier to deform in a controlled manner. I think it's an experiment worth trying. I can remove some ridges now, and some after the flask hardens and dries.

Could you tell me what animal your horn is off .ive never seen one with a tip that was solid that far before thanks .

 

[CEvonk]

Could you tell me what animal your horn is off .ive never seen one with a tip that was solid that far before thanks .

It is a cow horn that I purchased from Powderhornsandmore.com . It was listed as a "project horn" which was probably not suitable for making a power horn, a "reject," but one that might be useful for some other project. When you buy a project horn, they just pull a random horn from their box of project horns -- you don't get a choice as to color, handedness, size, or anything, so it's a pig in a poke.

I bought 2 nice horns and one project horn, thinking I could use the project horn for practice, and not mess up a nice horn. After examining the horn, I thought it would be worthwhile to try to come up with something usable from my practice efforts, if I could. Given the usable size of the horn, I thought it might make a decent flask for charging pistols, small enough to fit in a coat pocket or possibles bag.

I just measured the volume of the horn, and it holds 6.5 ounces of water. I'll lose some volume to the plug, so call it a 6 ounce horn. That is 177 cc. At a density of roughly 1.75g/cc for black powder, that means the horn should hold around 309 grams of powder, which is just under 11 ounces, or 309g x 15.43 grains per gram equals 4,635 grains. So if completely full, it should hold enough powder for about 132 charges of 35 grains, which is what I typically use in my CVA "Kentucky" pistols, or 257 charges of 18 grains for a .36 caliber revolver.

 

[BillinOregon]

CE, are you by chance an engineer? I ask because you seem to approach things both logically and methodically.

 

[CEvonk]

CE, are you by chance an engineer? I ask because you seem to approach things both logically and methodically.

I own a white hard hat, but have never worn one professionally.

 

[CEvonk]

Today I managed a little time on the project.

I first opened up the spout hole from 3/32" to 1/4" by the hole several times, and stepping up drill sizes 1/32". By not biting a lot of horn with the drill bit on each pass, it is easy to control the drill if you are drilling by hand. I could have used the drill press, but it would have taken more time to rig up a jig to hold the horn than it took to drill by hand. I ended up with the spout hole pretty close to perpendicular to the cut surface of the tip end of the horn. It's a tiny bit off in axis, but not enough to matter. There is enough "waller" in the cutting with the hole saw that I was able to make the threaded tip part perpendicular despite the fact that the pilot hole is not perfect.

Once the spout hole was opened up to the 1/4" diameter of the hole saw's pilot bit, I marked the hole saw at 1/2", 5/8", and 3/4" all the way around the blade, so that I could gauge my depth. I wanted to end up with a 3/4" depth. The depth of cut ended up being 0.730" inches which was close enough. It is important to use some oil on both the hole saw and the pilot bit, and also important to clear the hole frequently, as the horn shavings mix with oil and take on an almost wet particleboard texture, and they clog the teeth of the hole saw. I guess I pulled the saw and cleared the teeth about every 1/8" of cut. The oil also keeps loose, floating dust from happening.

Having hole sawed the horn spout shape, I next marked a 3/4" line from the tip end of the horn and used a hacksaw to cut all around until the excess horn came away. I made ten small marks at the 3/4" distance from the tip, all around the horn, and used the hacksaw blade to slowly work around the horn about 1/16" deep, which allowed me to make a nice straight cut around the horn. I continued cutting shallowly for several passes, untill the excess horn came away as a ring with a 3/4" hole. I managed to get a fairly flat cut. Then I sanded up the cut and the spout.

So here's where things didn't go exactly as I wanted, but not badly enough to be a big problem. I wanted to make a 5/8"-11 thread on the spout tip, but that requires a minimum major external thread diameter of 0.6113". My spout tip measures from 0.5525" to 0.5475" in diameter (smaller near the base.) I'm going to have to use a 9/16-12 thread, as that allows external major diameters of 0.5495". Next time, I will use a 7/8" hole saw to cut the plug. It's not a big deal, it's just a deviation from the original plan.

In the pictures of the horn tip here presented, the marks on the outside of the tip are not threads, just marks from the hole saw.

All in all, it came out fine. I will reshape the end of the horn so that the spout is in the center of the horn, and I'm still thinking of a bee-hive style pewter cap for it. I have to think about the next steps, and order a tap and die set for 9/16-12 threading.