making a cannon

It was an art. For big cannons, they mixed the alloy as they went, because tin, like zinc, will separate from copper in a melt if you don't agitate it.

The one bronze alloy that doesn't require stirring is silicon bronze, which is fairly strong and corrosion resistant, and widely used for marine hardware. I wouldn't put gunpowder in it for love nor money, however.

I'm not sure what the story is there. IIRC, it's a matter of compression strength. Cartridge heads tend to part ways with the rest of the cartridge at around 60,000 psi. I recall this because I once shot an overheated handload (then wildcat) .25/06 in an '03 action that, fortunately for my eyesight, had the Arisaka-type recess modification. It still scared the daylight out of me. d8-)

Typing is free, unless it's for publication. d8-)

-

Besides selling test kits, they will also

-test samples in their shop.

I learned how to analyze metals in chemistry class but don't do it at home because I can't dispose of the resulting hazardous materials, and nitric acid fumes will attack almost everything in the house and shop.

A reasonably accurate tensile strength testing machine wouldn't be difficult to make. it won't tell you what the alloy is you can find out how it behaves under load.

The sample size could be adjusted to keep the pull within the range of a bathroom scale. The (ab)used tensile strength machine scale I have goes to

600 lbs. It contains a loose-fitted carbon piston and cylinder damper to protect the mechanism from shock when the sample breaks.

To use it you increase the tension with a turnbuckle or comealong and record the pull and specimen length at convenient steps of length or force, depending on which you can read more precisely. When you reach the elastic limit the effort to stretch the sample stops increasing as quickly. It's the same as realizing when you have overtorqued and started to strip a bolt.

The test sample is a dogbone-shaped strip of your unknown alloy turned cylindrical between two attachment bolt holes. Parted-off rings are said to be suitable though I haven't found a good description of the preparation and procedure.

I don't have a permanent testing machine. When I want to test something I set up the equipment between two large trees.

jsw

Nasty.

Hmm ... I've got some, but agree that putting powder in it would be a bad idea.

[ ... ]

The pressure first expands the walls, gripping the chamber firmly, and then excess pressure tries to push the bolt back (or bend the frame in a revolver), thus leading to head separation.

I'm not familiar with the Arisaka modification, but it sounds like a good thing that you had it. :-)

[ ... ]

Remind me not to publish anything other than what *I* write. :-)

Of course -- legally in the Patent world, posting the information here counts as publication and starts the one year timeout by which you have to file your application. :-)

Enjoy, DoN.

So it's a failure in tension. Hmmm. If I get bored some day, I'll have to go back and look into it.

Oh, yeah. That was in 1961 and I was 13. I forget how that recess is arranged, but it was a strong point of the early-WWII Arisakas, and some builders of custom '03 sporters after the war adopted the idea to make the '03 safer in case of a cartridge failure.

Ah, I think you're thinking of something to do with patents or foreign copyrights. In the US, your work is automatically copyrighted, and you don't have to file anything. It's been that way since 1978 or thereabouts.

I *did* say "in the Patent world" above. Once your invention has been published, you have one year to get the processing of the patent application running. This from the patent lawers at the lab where I used to work.

Enjoy, DoN.

Darn, I missed that and just hung on the word "publication." Selective attention, I suppose. d8-)

Yes, patents are something else.

No longer works that way, I suspect. Congress changed US patent law a few months ago. We are going to the first-to-file system, versus the original first-to-invent system. (The rest of the World uses first-to-file already.)

Joe Gwinn

first to file or not, once an idea is published the timer starts running

- a patent can then be invalidated by showing that publication as prior art