Author Topic: Locks, Then and Now - just some thoughts  (Read 2436 times)

Offline JCKelly

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Re: Locks, Then and Now - just some thoughts
« Reply #50 on: June 01, 2019, 07:30:10 PM »
"Blister Steel" was the most commonly available heat-treatable steel of the 18th & 19th centuries. Used for cutting tools, springs, anything requiring decent hardness and strength. 
Metallurgy 101 - the difference between elemental iron (close to nails, common mild steel) and STEEL that can get hard is carbon.  Nails & such might have about 0.1% carbon, or at least something less than 0.2% carbon. Steel, from which one can make stone chisles, springs, swords files &c has anywhere from 0.6% carbon up to about 1% carbon.
Wrought iron has almost no carbon, say less than 0.1%
Ya want it to be hard, gotta caseharden it (pack in charcoal & heat red a few hours) Surface then picks up 0.6% or more carbon, and hardens when you quench it from the pack.
Want a solid bar of fairly high carbon steel?
Take several bars, usually flat skelps of wrought, iron, pack them in a lot of charcoal & heat the whole mess very red hot (say 1750F) for about 24 hours. This case hardens the $#*! out of them, maybe half way through the bar. Take them bars & forge them together to get a more even mix of carbon through the metal & you have blister steel.
Huh? Why blister?
Oh, that wrought iron is filled with slag stringers. That slag is a mix of some silicates and iron oxide. When carbon diffuses in to those iron oxdes, that carbon reduces them to plain old iron, and carbon monoxide gas.
The gas raises blisters on the surface of the iron. So before you use the stuff you must hammer down those blisters, close them up.
The best steel at that time was so-called "cast steel". Uniform in carbon throughout, no blisters.  It was not a casting. Just called that because you start out with blister steel and melt it, CAST it into an ingot, and forge down to bar.

Bonus round: All metal is a mix of crystalls, which us metallurgists calls "grains" Normally they are too small to see with the eye. If you seen bright shiny crystals on a broken piece of steel, they are way, way to big. Eiher it is a forging, as-forged, or you heated it too hot in heat treatment.
You can refine these grains, make new smaller grains, by heating the thing a nice red & coolng it in air or justy lay it on the ground. Then when you heat it again to harden it, it will have reasonably fine grains & make a tougher Widget.

Aren't you glad you asked? 

Offline D. Taylor Sapergia

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Re: Locks, Then and Now - just some thoughts
« Reply #51 on: June 01, 2019, 07:45:02 PM »
It never hurts to refresh one's knowledge of this stuff, so thanks Mr. Kelly, for the review.
D. Taylor Sapergia
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Art is not an object.  It is the excitement inspired by the object.

Offline Craig Wilcox

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Re: Locks, Then and Now - just some thoughts
« Reply #52 on: June 01, 2019, 08:49:50 PM »
Thanks, JCKelly - that was a well-thought response to the questions!
As a biologist, I can describe leaf cells, and the photosynthetic theory of operation, but have had almost nothing to do with metals other than 4130 steel I used to build airplanes with.  It hardens well, but is rarely heat treated.
Craig Wilcox
We are all elated when Dame Fortune smiles at us, but remember that she is always closely followed by her daughter, Miss Fortune.

Offline rich pierce

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Re: Locks, Then and Now - just some thoughts
« Reply #53 on: June 01, 2019, 10:19:46 PM »
Blister steel is iron sheets cooked surrounded by charcoal then forge welded together.  The sheets often had a blistered appearance. 
St. Louis, Missouri

Offline JCKelly

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Re: Locks, Then and Now - just some thoughts
« Reply #54 on: June 02, 2019, 02:27:22 AM »
Skelps

Offline Hungry Horse

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Re: Locks, Then and Now - just some thoughts
« Reply #55 on: June 02, 2019, 06:36:02 PM »
TimM;

  You must be hunting Californias A zone deer season. I hunted it for forty years. Itís some of the hardest hunting in America. I love hunting black tails with black powder, but often opt out because of the dry terrain, and fire danger. Back to flintlocks, a good one creates an incredible shower of sparks, instantaneous ignition, and intense fire emitting from muzzle, and touch hole, making it a fire starting machine, and we havenít even mentioned the smoldering patch.
 I have had many upper end antique production locks apart, and have found few that compare to the upper end production locks of today. The only possible caveat is in the quality of the springs used in upper end antiques, they are consistently better than the cast springs used today.  If you start talking about a hand made lock from one of the premier makers back in the day, thatís a entirely different discussion.

  Hungry Horse

timM

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Re: Locks, Then and Now - just some thoughts
« Reply #56 on: June 03, 2019, 01:48:42 AM »
HH, I share your 40+ years of A zone deer hunt.  Definitely dry country during season.  Great tune up for an annual Rocky Mtn. Hunt......been a life long bone collector. 

My experience with antique guns and their locks has mostly shown me nothing extra ordinary, good guns having reasonable locks.  Chevy's and Fords I think.  Again, maybe nothing changed, good riflemen knowing their piece and what keeps it shooting.  As you and others have pointed out in this thread, some great locks available today.