This test was done to test out a new way of pinning the knife together. The method was introduced to be by the renowned Todd Davison after seeing a similar test he performed. The previous method I was using required making a bushing / washer / reinforcement from some rod and drilling a pivot in the middle of it. Without having a lathe this is a big pain to try and get right.
Here is the test subject. A 3/32 inch thick O1 blade that have been flat ground. I was using this as my experimenting blade for a through hole opening hole which didn't turn out the best so it is good to be able to re-use it for this test. The blade has been heat treated and was tempered at 200 degrees Celcius twice for 2 hours. The "scales" are natural style G10 and I am using a 3/32 stainless pin. There are no washers or bushing around the pivot. The blade rotated freely around the pin before we did the test.
Ready to go in the vice. We figured the weakest point would be where the opening hole was in the blade so we made sure that was below the level of the vice jaws.
We used some spare square section RHS tube as a lever so we could really get some force on there.
Starting off .. slowly does it
SNAP! caught on camera the moment the blade snapped.
Inspecting the damage. The pin didn't move from its initial position at all and the blade still pivoted without any problems at all.
You can see that it snapped at the edge of the nail nick. Guess we were right about the weak point then.
Since the blade snapped at a weak point and there wasn't really any bend in the blade at all we thought we should do another test to make sure we really stressed the pin out.
Round 2.. !!
Bent to about 45 degrees before something gave. I thought it was the pin snapping since the handle didn't seperate from the blade like in the first test.
A nice view of where it gave way. Right against the edge of the scales and some bend against the jaws of the vice.
Trying to see if we could still check the pivot. Unfortunately the bend in the blade meant we couldn't rotate it. Not sure if you can see it in the photo but there is a crack where the stop meets the tang.
Some more views of the damage. Nothing to the pins though.
It's fixed! Now that is a nice trick.
After all the fun we tried to bend the blade back to see how the pivot pin had gone. Unfortunately it snapped off inside the liners. On the plus side I can stick a screw driver in the gap and spin what remains of the tang inside around without too many issues.
Big thanks to Karim of Tharwa Valley Forge for taking photos.
Extra big thanks to Todd Davison for answering my questions about his method. You will definitely be seeing featured on my linerless knives from now on.