But the pivot is too sensitive to moisture, is typically finicky. The lockring is a hassle that has resulted in a cut on occasion, and there is no heft to them at all. They just don't do it for me, especially when SAK's are so comparably cheap. Give me a Cadet or Electrician for another $5-$10 any day.
I do love Opinel knives but I can't carry them in my pocket, especially in summer cause when wet they are hard to open.
As noted above, they require maintenance, which may not be to everybody's liking.
Friction is controlled primarily by the inner ring, which can be opened (flat head) or closed (peen the pivot or grimp collar with pliers). Moisture is managed with regular application of mineral oil or Vaseline.
IMO, the lockring locks better if the ramp on the top of the outer ring is filed a bit to allow the ring to spin about 1/4 of the way around. I used to be similarly frustrated by the lock ring but having learned to tune them, I find them easy, reliable and infinitely more durable than any other lock I've used (Buck, Schrade, CRKT, many others). Details here:
https://dl.dropboxusercontent.com/u/28597626/tuning-opinels.txt
I'm not sure that heft translates into anything. I've busted several Victorinox knives and wrecked several Bucks. Never got an Opinel to fail.
I got my first opinel maybe a month or so ago. I like it quite a bit. Today, I put it to the hardeat use I generally put any knife through. I butchered one of my goats with it. Now, when I started, I was flabbergasted. It worked fantastic. But to be honest, it does not retain an edge like my sharpfinger, or buck 110 that I usually use. If I was better about not hitting bones, it would be awesome. I had to resharpen 3 times, then I gave up and finished with my case sodbuster jr. now, that was a pleasant surprise. I did not intend either knife for this purpose in the first place, but I decided to try. It works well if you have the patience to keep re-touching the edge. it was a no 8 in carbon. perhaps I will try a 7 inox.
Is your Sharpfinger an old USA Schrade? The old Schrades were hardened to 58Rc or thereabouts, both with their 1095 and their Schrade+/440A. I find the Opinel Carbone (1085ish at around 56Rc) to be tough but not great in terms of edge retention. Another problem is that if sharpened too thin, the edge on the Carbone can fold easily. If working hard, I keep mine at 25degrees per side. If you use a more accute angle and were hitting bone, that might explain it.
I have several old Schrade 1095 blades and have had many Buck 420HC blades. I find Opinel's Inox (Sanvik 12C27 at 58-59Rc) to be on par with (old USA) Schrade's 1095 and better than Buck's 420HC in terms of edge retention. That's not super steel by any stretch. Buck's old 440C will hold an edge for game cleaning longer.
With concrete the locking ring gets jammed up fairly easily, so it either wont engage or wont engage well causing your fingers to slip and possible cutting yourself on the blade.
As we discussed in the pass-around, I think this is exasperated by how small the #8 is, compared to the #9 and #10. I find the #8 too small to operate with gloves on, the #9 just barely big enough and the #10 easy to use with gloves.
I was never clear if the ring totally jammed on you or just got real gritty. I've dragged mine through sand and not every had a ring jam on me. But concrete may be different.