In the UK gunmetal is a type of bronze.
early cannon were made from bronze because it was easier to cast and less brittle than cast iron.
cannons exploding was a common problem though
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Hi all
Gunmetal is bronze, in addition to copper and tin it had up to 4% zinc giving it the grey colour. The blanks would not have had the zinc added but may well have a small amount of manganese or phosphor to give them hardness of wearing. Again like keyhorses there is no single metal called bronze there are hundreds with differing percentages of differing constituents to match the use. For working on locks on magazines up in the Buxton quarries they used to take my tools off me and give me a tool set entirely made of bronze. Spanners, hammers and all. I even made an odd specialist tool myself. Things don’t seem quite so explosive these days as we are working on a magazine next week and they are even allowing drilling if necessary (better not be!) possibly the design of the stores are much improved and the ‘stuff’ isn’t just lying around inside like it was in earlier times.
Chris
I posted this years ago, but it is relevant here, and stands retelling.
When I was very young, in the late fifties, there was a safe breaker in the Castleford area whose trademark was that he always used far too much explosive. He once sent an escutcheon through a wall!
Any road up, he was running out of explosives, so decided to steal some from a colliery magazine. (You can see this coming). What better way to open the magazine than blowing the locks. He was never found, not was most of the magazine.
That might qualify for a Darwin Award.
He had a go at a Chubb banker and bent the door almost double, which is no mean feat, but didn't get into it.
Hello Chris and a big welcome to you.
Just to add for those interested Gunmetal and leaded bronzes are still widely used and in raw form like bar and pipe they show a characteristic banding pattern from the zinc and lead content that you dont get so much with other grades. You cut through this skin when machining so the banding disappears but you still get traces of grey clouding on the surface. its brilliant stuff, cuts beautifully and is well suited to certain bearings and gear combos, couldn't be without it.
Attachment 19623 Attachment 19624
Here's a visual comparison of a few very different bronzes in bar form, from left to right they are aluminium bronze, gunmetal as above, porous oilite and phosphor bronze. Unlike gunmetal, aluminium bronze can be a pig to machine and tap and I dread to think how much a stub of it this size would cost now!
Attachment 19625
BTW Gary I saw the dual Chubb on eBay but been that sidetracked with things i forgot to bid on it, have you picked it open yet?
I remember being surprised that UK bronze coins can be picked up with a magnet.
I haven't received it yet Huw, but may have a masterkey for the second keyhole, if not I have made a two in one and will have a go with that when it arrives.
got the double keyhole version of the deposit wallet that I bought on ebay, the masterkey I have did work to open the unit, but had to test drive the pick I made as well, tricky little things to pick and a lovely compact little lock, just have to make keys to it now.