Drop Forged?

M

Man with no name

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What does it mean when a blade is "Drop Forged"? How is it different from standard forged knives? The reason I ask is Cold Steel is offering a Drop Forged Bowie, Survivalist and Boot Knife. All are made from a single piece of steel including handles.
 
It's just a method of forging. Also known as impact impression die forming. Dies in the shape of the desired part are made and the top die is hoisted and then dropped on top of the bottom die, then the excess material that's squeezed out the sides ("flash") is trimmed away. It's an economical method of repeatedly creating near-net forged shapes. Most of the cost of those knives is in the finish work and sheaths, as well as paying off the very high cost of the dies, but the unit cost of the forgings is extremely low. Because of the cost of the tooling but massive cost reduction of the per-unit product drop forging is usually used only when you're going to be producing a large volume of product.
 
So bar stock is heated then stamped or drop forged into shape by dies? Is this done in one stamping or does it take several attempts?
 
Depending on the particular tool it can be done in one stage or it may require multiple dies used in succession.
 
I have seen an old drop forge make parts, and a massive block of metal was dropped from a height (using rope and pulley in this case) and stamped out the parts --1 or more stampings (of precious metals for items in the $40-60K price range, so not cheap crap). Then the parts were trimmed/ heat treated and finished.

This equipment is no longer used/legal here-- probably for safety reasons or age (I'm not 100% sure)--at least not this particular set-up--and had been grandfathered in due to it's purchase ca. 1888. When the company relocated, the drop forge (built mid-19th C.) was decommissioned.
 
Interesting information. Just for comparison how are non drop forged factory knives forged? For example Cold Steels Trail Master? Would these knives be CNC machined? The product catalog says "they are precision ground, heat treated and Mar Tempered in their state of the art factory".
 
Man with no name said:
Interesting information. Just for comparison how are non drop forged factory knives forged? For example Cold Steels Trail Master? Would these knives be CNC machined? The product catalog says "they are precision ground, heat treated and Mar Tempered in their state of the art factory".
Click to expand...

That's what's referred to as stock removal. Blanks are cut from sheet or bar stock and then machined to shape. Most knives these days are made this way, but forging is still used for some knives that have things like integral bolsters that increase their maximum thickness beyond what's reasonable to machine. If you have a knife with an 1/8" spine but a 1/2" thick integral bolster it doesn't make sense to CNC the whole thing out of a 1/2" thick bar vs. forging it out using impression dies.
 
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