Half Stops

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Sep 28, 2014
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693
Howdy Y'all,

If this has been covered, I couldn't find it. I've never actually understood the purpose of a half stop. I don't think anyone actually uses a blade in the half open position, do they? Anyway, please enlighten me as to the reasons for their existence.

Thanks!
 
From what I have read, there's no clear consensus. Most cite that it is a safety feature, helping to prevent the knife from shutting on one's fingers. Some assert that it reduces the wear on the spring to some degree, but I don't know if I buy that given that the spring spends the same amount of time under tension when opening, with either a rounded tang (no half stop) or a flat tang.

To some degree, I could see how a half-stop would make a knife safer as it aged or if it became loose at the pivot. A blade that swang freely when not in the fully open or closed position would be a real hazard, and a half-stop would ensure some measure of controlled closing regardless of pivot tension.

Edit: From a material physics standpoint, a square tang engages a significantly smaller amount of the tang to the spring. Almost the entirety of a rounded tang will meet the spring, whereas a square tang only engages the corners of the tang against the spring.

Additionally, there is some speculation that it was a safety measure brought about by older slipjoints having very strong backsprings, which made the half-stop a bit of a safety feature in that you had a halfway point to prevent the knife from snapping shut with force if your fingers were to slip, or if you were careless, etc.

Edit II: They can also act as a bit of a self-cleaning feature, as the tang of the blade scrapes against the spring (instead of sliding along it) which can help prevent / remove gunk buildup.
 
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Yes, there will be some difference in wear. With the round tang all the wear is concentrated on one spot. With the half stop the wear is distributed along the spring, equal to the length of the flat of the tang. I am not sure how much difference this would make on a well oiled joints. Not long ago someone posted a photo showing a spring which had been worn to the radius of the tang to the point where the blade could not close.

Wolfe
 
However it wears, I have cut myself more times with a knife sporting a half stop than one without when closing the knife.

I can live without them, but they aren't a deal-breaker.
 
The only "blade" with a half stop that I would consider using in the half open position is the screwdriver/cap lifter blade on my SAK 'Recruit', if I needed a bit more torque to break a screw loose, or while tightening.
I think they were originally a safety feature, as well as a chance for the cutler so show off his skill, by having the back spring flush in the closed, half open, and full open positions.
 
As I understand it, some newer knives are made with (or without) half stops because that's the way the original pattern was made a century or more ago.

As for the originals, I really have no idea but the posters above have provided some excellent insight.
 
Prevention against snapping closed on one's finger - that's a good point I hadn't thought about.
 
I'm not educated concerning the history or real purpose for the half stop, but it just so happens my two most favored knives(at this moment) have half stops. I dig it, but like others it's not a required feature.
 
It was probably a safety feature originally so that the blade would snap into the half open position instead of snapping closed. It has the additional benefit of helping to remove gunk/lint/etc from the backspring area. I like knives with or without half stops.
 
I don't really care for them and much prefer a round tang.

I don't have the reference handy but I believe the square tang was the original (only) style around for a while when springs were first added to friction folders in the 16th or 17th century. The round tang came later as an invention to improve on the square tang, I believe it was introduced as a way to mitigate spring wear.

Note also that for the most part a modern steel knife will have little to no wear over its lifetime if kept reasonably clean and oiled. Our steel and finishing levels are much better than now than centuries ago. Spring heat treatment has come a long way and a polished tang should have millions of rides before any wear shows up.
 
I once read that the half stop purpose was a point to stop and reposition hands or fingers to finish opening it without it snapping closed on you. After reading that, I noticed that's exactly what I did with mine with half stops naturally (and I don't on the ones without).
 
I don't have the reference handy but I believe the square tang was the original (only) style around for a while when springs were first added to friction folders ... The round tang came later as an invention to improve on the square tang, I believe it was introduced as a way to mitigate spring wear.

Quite right sir, invented by the French, and regarded as a very significant improvement at the time :thumbup:

This topic comes up very often here.
 
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I can't figure out how someone cuts themselves on a knife with a half stop.

I'd just as soon all slipjoints have them. But on knives with stout back springs, I can definitely see a very practical purpose they serve. I wouldn't use, say, a Douk Douk if it didn't sport that half stop. It's too much of a bear trap.
 
I can't figure out how someone cuts themselves on a knife with a half stop.

I've done it several times. It happens when you first get the blade over that first corner and it shifts from wanting to close to wanting to open. If the spring is very strong and the half-stop is very defined there is a sudden change in force. The blade used to be pushing against your thumbnail that's in the nick, and now it's pulling away. What happens is your nail slips out of the nick and you don't have time to react, so you're still pushing with that thumb. The thumb slides up past the blade and the edge catches on your knuckle. My 23 has caught me a couple of times like this, especially when it was new and I wasn't yet accustomed to it's mighty snap.
 
What Cory Hess explained has happens to me a few times aswell. I prefer them not to have stops but its not a deal breaker. I never have cut myself closing a tightly sprung knife with or without half stops.I have Nicked knuckle opening knives with stout springs with half stops.
 
Though not a deal breaker, I prefer half stops. Seems my old knives with half stops keep they're original walk and talk stronger longer.
 
I have never cut myself closing a knife without a half stop but have managed it about four times in the last year since I started collecting GEC. My cuts occur when I am closing the blade to halfway, thinking that my fingers are in a safe position.
 
Quite right sir, invented by the French, and regarded as a very significant improvement at the time :thumbup:

This topic comes up very often here.

Just like Stainless Steel, we don't need any of that new fangled, roundy round tang nonsense! [/gravely, Deep, Slow, Mississippi Accent; /suspicious eye casting; /furrowed brow] :D
 
Just like Stainless Steel, we don't need any of that new fangled, roundy round tang nonsense! [/gravely, Deep, Slow, Mississippi Accent; /suspicious eye casting; /furrowed brow] :D

Accusations have been made that the Sheffield cutlers were slow to adopt the round tang as they foresaw it would ultimately lead to them making less knives! :D
 
I do not prefer half-stops, but it wont prevent me from buying a blade combo that I like. The half-stops have never saved my fingers. In fact with stiff springs, on opening, I find it a little scary when the blade jumps out of your fingernail and flies open to the half-stop. A knife like this, I either adjust how I open (barely open, then pinch to the half) or I sell/trade it off.

Good example 53 vs 54 pattern. Only difference is half-stops and the blade combos over the years. I have both because certain blade combos have only been made available in the 54 (with), while I prefer the 53 (without).
 
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