Trauma Scissor Metal Choices

Which metal

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Oneshear

Joined
Mar 27, 2019
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Hello,

We are manufacturing Trauma Shears and currently using J2 420 Hardened steel with a DLC coating. We are looking to increase our quality of metal to prove worthy of the market.

We have considered M390, 440HC, A2, VG10 and open to ideas.

Please help us out and give your thoughts.

We are looking to cut through clothing, jeans, zippers, boots, leather, and potential thin metal.

Thanks
 
If you were looking at making something for a tool shed, then maybe something in A2 might be good, but I think it would take too much maintenance for real trauma shears. I would stick to steels that were more reliably stainless.
Others may post their opinions, but in my use of trauma shears, they are better off being closer to disposable than high value items, and the pivots are where most manufacturers cheap out, which is the most critical part of the design.
 
Must be stainless, must be. Past that, 420J is fine. Not too many will use them enough to dull the edges, and then they will almost certainly just buy new
 
H0kieengineer said:
Must be stainless, must be. Past that, 420J is fine. Not too many will use them enough to dull the edges, and then they will almost certainly just buy new
Click to expand...
Frankly, I'd be shocked if an EMT managed to keep a pair of shears long enough to dull them. Even an entire service.
 
If I were making an heirloom quality scissors, I would lean toward 440-C hardened to 60 HRC. These would cut unhardened metal like nails, staples, sheet metal, woven cable, etc.
 
Would that hard of 440 still have the spring required to allow the shears to function properly? All the shears I've used seem to use the flex in the handles to keep the two blades pressed against each other. I've seen really old fabric shears that had flat-springs in the pivot to provide that tension. Adding springs seems that it would add significant cost.
 
Thinner curved blades would be one solution. Stiffer curved blades with a coil spring and tensioning nut at the pivot would be another.
 
Something that's stainless is a must. But also something that resists chipping and some what tough. And good edge stability. Sheer resistance is also necessary if your cutting metal and zippers with. I wouldn't worry as much about edge retention as those other properties for what your seeking.

The sheers I see out today often get rusty. They will see blood, sweat and humidity. So this is important. I've not seen any trauma shears with Dlc coatings myself. That could be helpful for steels less corrosion resistant.
 
Greetings, everyone. First time posting on BladeForums, but definitely not my first visit. I'll share my experience here and maybe it will help the OP.

My company went through this same decision process around 12 years ago. We knew from extensive personal experience that we needed something with good edge retention, durability, and corrosion resistance that would survive for extended periods in a maritime environment while remaining affordable for the end-user (civilian and military first responders were and are grossly underpaid). We also knew that trauma shears were considered semi-disposable AND highly pilferable (it's amazing how quickly they grow legs when unattended). Given that we were both in the middle of demanding training and deployment cycles, we had to make an effective choice quickly and run with it. We opted for hardened 420J2 with a TiCN coating, as the TiCN was roughly eight times harder than the underlying 420J2 and highly corrosion- and chemical-resistant.

We were concurrently developing our Ripper attachment based on the prototype my colleague had bolted on to his trauma shears and used to crush the trauma lane times at the 18D long course in Ft. Bragg. Our RS-1 Ripper required a different steel for the razor blades, along with stainless hardware. Based on the recommendation of our razor blade manufacturer, we went with passivated 440A with a tungsten DLC edge treatment for lubricity and edge retention, which was a significant upgrade to the carbon steel blades we typically found on our issued hook knives that were useless after one or two water jumps. We sandwiched the blades in a 13% glass-filled nylon housing with stainless screws and custom threaded stainless inserts to ensure reliability from -40F to 290F (basically the annual temperature range found in Afghanistan, plus the inside of an autoclave).

Were/are other higher-grade steels available? Yes, but we were both active duty military and 100% self-funded, so we went for the best bang-for-our-buck. We later upgraded the scissor pivots to coated stainless after seeing some of our first-generation shears returning from the water with rusty pivots. We have stayed with 420J2 and 440A over the years to keep from pricing ourselves completely out of the competition while delivering a superior product. Even so, despite tight margins, we can't match the bargain basement prices of some well-known garbage-peddlers and have lost contracts that only specify trauma shears rather than scissor performance metrics, or bolt-on attachments. However, we knew we had a solid product when a certain huge multi-tool company began developing a derivative design six months after we hit the market and took another 18 months to debut their folding scissors and hook knife combo, at more than twice the price with half the speed, so we have remained undaunted.

Our razor blades, injection molding, and final assembly are all made in the USA, but we import our 7.25" trauma shears and 5.5" RS-4 Mini Ripshears. We spend our first two years trying to find a US scissor manufacturer that could meet our requirements, to no avail. If anyone has a company to recommend, please do so, as we are currently exploring domestic options.

Thanks for your time!
 
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