Armstrong RML. Roughing Out the Barrel
by John
Today was humid. But I hardly noticed. I was attacking a piece of 72mm diameter steel rod for the Armstrong 80lb model cannon barrel. Enough of the plastic printed shit. Now for the real material..
It was a piece of an axle. No idea of the exact material. But it is magnetic, turned beautifully. So not stainless.
The roughed blank, and the plastic printed model.
Next problem was to produce the 16mm bore, through 285mm.
None of my 5/8″ (15.87mm) or 16mm drill bits were long enough, so I drilled from both ends. Still have a substantial chunk in the middle. The cutting fluid is my own mixture of olive oil and kerosene. I used to grow and make olive oil and I have quite a bit left over.
The roughed barrel, ready for CNC finishing. And a 16mm drill bit which I turned down to a 10mm shank, and a piece of 5/8″ drill rod/silver steel drilled to 10mm, which I will silver solder to the drill bit to make it adequately long to drill through the whole barrel tomorrow.
The roughed barrel, and the 16mm drill bit ready for silver soldering. Yeah. It is a bit longer than necessary.
Turning cannon barrels is really satisfying. Still considering how to manage the rifling.
johnsmachines 
I always enjoy reading your updates. Building cannons is a lot of fun. Regarding rifling, I made a 110 pounder RBL a while back and I cut the rifling with a setup on my lathe. It was a ton of work though. I have a webpage about it here: http://jefenry.com/main/110PounderArmstrong.php
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Hi Jeff. Well, I have just spent a very pleasant hour or so reading your cannon builds. Particularly the Armstrong RBL. The rifling setup info is really helpful and I will probably copy it. I am so jealous of your ability to fire your cannons. Our Australian gun laws are very restrictive, (for very good reasons). After watching your videos I am inspired to approach the local gun club to see if there is any possibility of getting a black powder licence and maybe copying your example with the video, which by the way, was excellent! Thank you so much for sharing the info. I am a bit disappointed that my search engine did not point me in your direction earlier. John.
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I’m glad you enjoyed it! It’s been a while since I’ve worked on cannon models, but I need to finish up the carriage for the 8″ shell gun and I’ve made drawings for a 70 pounder Whitworth. It has a rifled hexagonal bore which would be a challenge. You might have found it, but there’s a forum were people make model cannons here: https://www.go2gbo.com/forums/88-blackpowder-mortar-cannon-sponsored-seacoast-artillery.html I know at least one Australian who built a copy of a Mary Rose cannon and got permission to fire it. They are a ton of fun to shoot, especially if you have something other than paper to shoot at.
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Hi again Jeff. 2 questions for you. 1. What diameter did you use for the touch hole? and 2. How deep did you make the rifling grooves? I am thinking 0.1mm (2.5 thou). John
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Hi John, I drill my vents with a #36 drill (.107″ or 2.7mm), but that’s only because I use 2.5mm diameter Visco fuse. On US guns the vents were .2″ in diameter which enlarged to .4″ during use from erosion. After 500 shots they were plugged with molten zinc or lead and a new vent drilled for an additional 500 shots before the gun was retired.
I took the grooves to .020″ deep because I wanted to make sure they would work in stabilizing the bullet. .0025″ might be a little shallow to see? I’m not sure scale wise what they should be.
Looking forward to seeing your CNC rifling setup!
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Thanks for that info! Rifling is next process, but waiting for some tools to arrive.
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Oh. And I will correct my multiple mis-spellings of cascabel.
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Hi John !
I most certainly enjoy your updates. Alas, I cannot click ‘like’ without creating a wordpress account. Looking forward to seeing how you do the rifling.
cheers
Ben
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Hi Ben, I did not know about the necessity for an account. Maybe that explains why there are so few likes. I was thinking that I was missing the mark with the subject matter or style, or maybe too few videos. I appreciate the feedback! John
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