dsutton24
Gold Member
- Joined
- Apr 9, 2018
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How much force does it actually take to open a pocket knife blade?
I didn't really know. I knew that some blades are hard to open. Some open easily, and some are thumbnail busters. I think that GECS tend to be on the heavy side. You often see people rating blade opening as 'pinchable', a '7', and what have you.
But how much force is really required to open a blade?
So, in the interest of something or another, I rigged up an apparatus:
It's Wheeler trigger pull gauge and a sling made from one of those Amazon envelopes that can't be opened without power tools. The knife pictured above is my every day knife, an old Henckels 1901. I opened it several times, trying to find the lowest opening force, and found that it took 2 pounds, 4 ounces, or 36 ounces, to open it. This knife is my ideal, and I was surprised that it took over two pounds of force to open it.
Next, I tested an old, well used 2 dot Buck 110. It measured 24 ounces.
What does it take to actually break a thumbnail? I tested the cap lifter blade of a Camillus Scout knife, one that has actually busted my thumbnail. It came in at an impressive 91 ounces.
What about others?
I used my sling and scale gizmo to measure a few more knives. I centered the sling over the nail nick of the knives that had half moon nail nicks, and over the tip end of those with long pulls. I found that by holding the scale still with my right hand, and rotating the body of the knife with my left hand I could produce reproducible results. I measured the force from fully closed to the 45 degree open point. All measurements were converted to ounces for simplicity's sake. Each knife got a fresh drop of oil in the pivot, and was opened and closed five times to work it in. I measured only the master blade.
I tested all 10 of my GEC 71s. Not picking on GEC, I just happen to have a bunch of 71s, and it was interesting to see the variation on a number of the same knives. I generated ten random numbers and tested six more traditional pattern GECs, and did the same with six more traditionals from other manufacturers. I measured six out of ten because a few knives would pinch the sling against the liners and give false measurements.
So, what did the numbers say?
First, the Bullnoses. They are snappy. They ranged from a low of 35 ounces to 72 ounces, averaging 56.1 ounces. The 35 ounce knife was an outlier, most were well above that number. One of the knives was rated a '7' by a previous owner, and came in at 72 ounces.
The six GEC traditionals ranged from a low of 28 ounces to a high of 66 ounces, for an average of 39.67 ounces.
The six traditionals from various manufacturers ranged from a low of 24 ounces to a high of 42 ounces, for an average of 35.33 ounces.
So, of the knives tested, Bullnoses are really snappy. GEC averages about 4 ounces above the others, and most traditionals come in around 35 ounces.
The numbers:
Lastly, I took a brand new Case 6292, it measured 42 ounces. I left it partially opened at the point where the backspring was stressed the most for two weeks. Measuring it several times over the period didn't show a marked change.
The small ample sizes probably influence the numbers some, but I found this to be an interesting exercise.
Anybody care to add to the data?
I didn't really know. I knew that some blades are hard to open. Some open easily, and some are thumbnail busters. I think that GECS tend to be on the heavy side. You often see people rating blade opening as 'pinchable', a '7', and what have you.
But how much force is really required to open a blade?
So, in the interest of something or another, I rigged up an apparatus:
It's Wheeler trigger pull gauge and a sling made from one of those Amazon envelopes that can't be opened without power tools. The knife pictured above is my every day knife, an old Henckels 1901. I opened it several times, trying to find the lowest opening force, and found that it took 2 pounds, 4 ounces, or 36 ounces, to open it. This knife is my ideal, and I was surprised that it took over two pounds of force to open it.
Next, I tested an old, well used 2 dot Buck 110. It measured 24 ounces.
What does it take to actually break a thumbnail? I tested the cap lifter blade of a Camillus Scout knife, one that has actually busted my thumbnail. It came in at an impressive 91 ounces.
What about others?
I used my sling and scale gizmo to measure a few more knives. I centered the sling over the nail nick of the knives that had half moon nail nicks, and over the tip end of those with long pulls. I found that by holding the scale still with my right hand, and rotating the body of the knife with my left hand I could produce reproducible results. I measured the force from fully closed to the 45 degree open point. All measurements were converted to ounces for simplicity's sake. Each knife got a fresh drop of oil in the pivot, and was opened and closed five times to work it in. I measured only the master blade.
I tested all 10 of my GEC 71s. Not picking on GEC, I just happen to have a bunch of 71s, and it was interesting to see the variation on a number of the same knives. I generated ten random numbers and tested six more traditional pattern GECs, and did the same with six more traditionals from other manufacturers. I measured six out of ten because a few knives would pinch the sling against the liners and give false measurements.
So, what did the numbers say?
First, the Bullnoses. They are snappy. They ranged from a low of 35 ounces to 72 ounces, averaging 56.1 ounces. The 35 ounce knife was an outlier, most were well above that number. One of the knives was rated a '7' by a previous owner, and came in at 72 ounces.
The six GEC traditionals ranged from a low of 28 ounces to a high of 66 ounces, for an average of 39.67 ounces.
The six traditionals from various manufacturers ranged from a low of 24 ounces to a high of 42 ounces, for an average of 35.33 ounces.
So, of the knives tested, Bullnoses are really snappy. GEC averages about 4 ounces above the others, and most traditionals come in around 35 ounces.
The numbers:
Lastly, I took a brand new Case 6292, it measured 42 ounces. I left it partially opened at the point where the backspring was stressed the most for two weeks. Measuring it several times over the period didn't show a marked change.
The small ample sizes probably influence the numbers some, but I found this to be an interesting exercise.
Anybody care to add to the data?
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