Re: Locks
Posted: Wed Feb 08, 2023 7:00 pm
Hi TTFulltimer, Toomanyquestions,
Welcome to our forum.
sal
Welcome to our forum.
sal
Yes I have a probable cause. Have you ever tightened a Stainless fastener with a stainless nut? Ever have is literally weld together? That is because the coefficient of friction of stainless on stainless is GALL. My guess is with that forceful spring and working the knife so that spring keeps pushing the ball farther and farther into the wedge opening, you get some galling. Since it is a ball the contact area is very small so you can knock it free by wiggling the blade while pulling back on the screwball housing. Never had a back lock loosen from wear. The current Spyderco ones have a wedge like lock on the bar and in the tang of the knife. Wear will be taken up by the wedge.toomanyquestions wrote: ↑Tue Feb 07, 2023 6:45 pmIn your experience the CBBL lock occasionally jams? If so, do you have a theory about why this is the case? On the other side of the coin, I have heard back-locks can wear enough that blade wiggle arises. Has this been true in your experience?TTFulltimer wrote: ↑Thu Feb 02, 2023 6:51 pmMostly I open and close two handed. I prefer the back lock in every case. Liner lock second. That CBBL is a pain to use on the manix...And that screwball lock jams up more than it does not jam. Now you have to wiggle the blade to make it release. PITA for sure.
Thank you. I travel full time so am not in a known place a priori when the knife is ready to ship back. I cured the problem with a zirconium ceramic ball. I know that the useful galling attaching the first supersonic, curved, folding missile fin on a rocket that could do mach three on the deck certainly worked.Michael Janich wrote: ↑Fri Feb 10, 2023 10:24 amDear TTFulltimer:
If you own a Manix 2 that is not operating properly, we suggest you send it in for warranty evaluation. When properly adjusted and maintained, the Ball Bearing Lock will not "jam more than it does not jam." The process for returning a knife for warranty consideration is detailed on the Spyderco website: https://www.spyderco.com/service-suppor ... ty-repair/.
For the record, galling occurs any time two metal surfaces come in contact under pressure and is critical to the function of most lock mechanisms--particularly LinerLocks and Reeve Integral Locks/frame locks. It is not exclusive to a stainless-on-stainless context. Also, stainless fasteners--like screws and nuts--are typically austenitic stainless steels and are quite soft compared to knife blades and ball bearings, which are made of heat-treated martensitic stainless steel. Comparing the galling of soft stainless fasteners with the galling of hardened knife components is inaccurate and misleading.
Stay safe,
Mike
AgreedJoshLikesSekiCityKnives wrote: ↑Sat Feb 11, 2023 9:17 amBack Locks are king.
So much stuff comes out in liner and frame lock. It is hard if not impossible for me to find knives I like.
Aside for my Otanashi frame lock. I don't give a crap about drop shut or fidget nonsense. Gimme a reliable lock that some wear out from 3 to 6 months of use.
The engineer in me had to figure out what actually was going on. It came to me that the ball rides on two planes one on the blade and the other on the front spacer/ball actuation retainer. If the ball is hardened, and the Blade is hardened, and if the spacer were hardened, then depending on the blade steel hardness the ball would have to indent something. The contact of the ball on the planar surfaces is a point or a zero area contact. Any force will calculate as infinity in PSI. So the ball or the planes have to deform. I took apart the knife and sure enough, first the ground surface on the front spacer was corrugated and the ball had definitely left a small groove in the center of the plane it contacts. Makes sense the spacer is the soft part so that any HRC blade hardness is not deformed by the ball. I smoothed that portion of the plane as I kept hearing a scratchy sound as the cage was pulled back. Scratchy sound is gone ball will continue to travel in the groove it has made in the spacer. My thought is that the initial engagement with some hard blade usage set that ball into a pit rather than the end of a groove. Hence the difficulty in pulling the cage back. I think the harder ceramic ball was able to reprofile that pit easier than the steel ball. And there is still a coefficient of friction for hardened martensitic steels. The literature suggests that austenitic stainless can still gall against other steels.Michael Janich wrote: ↑Fri Feb 10, 2023 10:24 amDear TTFulltimer:
If you own a Manix 2 that is not operating properly, we suggest you send it in for warranty evaluation. When properly adjusted and maintained, the Ball Bearing Lock will not "jam more than it does not jam." The process for returning a knife for warranty consideration is detailed on the Spyderco website: https://www.spyderco.com/service-suppor ... ty-repair/.
For the record, galling occurs any time two metal surfaces come in contact under pressure and is critical to the function of most lock mechanisms--particularly LinerLocks and Reeve Integral Locks/frame locks. It is not exclusive to a stainless-on-stainless context. Also, stainless fasteners--like screws and nuts--are typically austenitic stainless steels and are quite soft compared to knife blades and ball bearings, which are made of heat-treated martensitic stainless steel. Comparing the galling of soft stainless fasteners with the galling of hardened knife components is inaccurate and misleading.
Stay safe,
Mike