I posted a thread condemning ball bearing pivot knives.
https://www.bladeforums.com/threads...ybe-not-so-much-now-opinion-changing.1466930/
This was a rather inflammatory post and triggered some rather negative reactions towards me. I have no problems with people disagreeing with me. I can be an idiot. Some are just attacking and some have valid points. Since then I have purchased three ball bearing knives and have come to a different conclusion, but not entirely in support of ball bearings in pivots. I promised to post my opinion after experiencing ball bearing knives after some use. Here is my updated opinion.
I now have 2 Harnds Talismon knives, 2 CH Knives CH3001 knives, and one CH Knives CH3504. There is a reason I have 2 of each of the former. I only have one of the CH3504 because it is only the most recent. I like all of them. All my other knives are washer type pivots with different materials.
There are many uses for knives. These uses can range from flipping at your desk for fun to survival use in the harsh elements. Some knives are clearly made for one extreme and others are made for the other. Folders are not the best use for survival situations and fixed blades are not the best for fun factor at the desk. There are always compromises. Always.
Bearings have been designed and refined over the decades according to their application. In general, plain (washer or bronze) bearings are applicable to slow speeds and high forces. Ball bearings are generally applied to higher speeds and lower forces. Plain bearings are generally better with static loads too. Knives mainly face static loads. If you are imposing a static load on a ball bearing it will have a much lower capacity than a plain bearing. The main benefit to ball or roller bearings is less friction at high speeds and in general.
It is hard to make a plain bearing that is permanently lubricated and sealed. This will have high friction and stiction. Ball bearings can be made that are sealed and lubricated for "life". This makes ball bearings more suitable for more variable conditions. High load static loads require the use of plain bearings over ball bearings. Remember? Compromise.
So how does this relate to knife pivots? There are conflicting requirements for knife pivots. Ideally they should be as friction free as possible, but also withstand possible high static loads without damage. These are conflicting requirements for both types of bearings. Which is best? It depends....
A plain bearing knife (washers) seems to hold the edge in low speed high force uses, such as in a knife. A plain bearing is seemingly less susceptible to easy contamination of the bearing surface if adjusted and lubricated properly. A plain bearing also seems to be more sensitive to adjustment of the pivot tightness, and to proper lubrication. A plain bearing knife will degrade very quickly with contamination of the lubricant between the bearing surfaces. This will mean disassembly, cleaning and lubrication. However it is extremely difficult to overload a plain bearing. No damage will result.
A ball bearing knife has the edge in low friction and ease of opening and closing. It has a deficit in handling high forces depending on the design. Depending on the bearing surfaces there could be problems with wear and brinelling. The best examples with hard balls against softer surfaces like titanium. One can get depressions in specific spots from large forces in one spot, tracks that get deeper over time, or pieces spalling out from repeated fractures from repeated movement and forces. If a knife has a hard surface for the balls to roll on then this is almost no problem. Ball bearings are also more exposed to contamination as almost every ball bearing knife has no seals to exclude contamination. This allows the contaminant to enter without impediment. This is a bigger problem for knives without hard surfaces for the balls to roll over. The benefit is that if there is a hard surface for the balls, the balls will just push the contaminant out of the way or just crush into non-importance. Because the bearing is open it is also easier to clean out the contaminant without disassembly. Flush, lubricate and move on.
IMHO, a knife with plain bearing system is superior for situations where there is never a chance of being able to clean or have access to flowing water or other cleaner, disassembly and reassembly. Tolerances will not change much and the opening and closing of the blade might get more difficult but it will not get so loose so as to cause a problem with lockup and safety.
On the other hand, ball bearing knives are superior if there are hardened steel washers for the bearings to ride on, that is if there are possibilities to clean any contamination from the pivot with water or some other liquid. Lubrication is much a less of a worry with ball bearings. If the bearing surface includes a soft surface like titanium, then cleaning , lubrication and adjustment seem to be a continuing concern. IMHO ball bearing knives that rely on titanium for their bearing surfaces should be considered light duty EDC knives and should not be relied upon for for your lost in the wilderness survival knife if SHTF.
Given my time with the knives I have listed as owning with ball bearings I would feel comfortable with each them as my only knife under the following circumstances respectively.
Harnds Talisman: Liner lock, AUS8, ceramic ball bearings on SS liners. I would feel comfortable with it as my only knife in any situation, but the onlooking public might find it scary. The AUS8 steel is a bit soft but easy to sharpen. The action is smooth and seems to withstand a bit of contamination.
CH Knives CH3001: Titanium frame lock, D2 steel, ceramic ball bearings against the titanium. This is probably my ultimate EDC, as in carry it anywhere. It is a big enough blade that I don't feel I am leaving capability at home. It is also much less scary for the public, and almost elegant. The problem is with this if I get lost in the woods it will last for a while but experiences has shown me that the ball tracks will get deeper in the titanium and make it unsafe after some period of time if I don't have the tools to correct it.
CH Knives CH3504: Titanium frame lock, ceramic ball bearings against hardened SS washers. This is a knife I would trust to not let me down in almost any situation where a folder would be sufficient, or even beyond. The bearings will not lose adjustment over time thanks to the hardened steel washers. Therefore the action will not die completely and the lockup should not suffer regardless of the contamination of the bearings and wear.
Conclusion:
My first rant on ball bearings was partially justified from my experience and knowledge, especially if the bearing surface is something soft like titanium. My first rant was also a bit biased. I feel that I am still correct about ball bearings in hard use knives, in that they are not the best design choice. But, in all practicality, my CH Knives CH3504 with ball bearings and hardened ball washers is a good compromise between ease of use, good feel, and durability. Ball bearings are not all bad but against bare titanium they should be mostly for light use. Ball bearings can be implemented in a good way, but one needs to be careful about what you buy and for what use.
Reference threads for the knives:
https://www.bladeforums.com/threads/ch-knives-ch3001-a-surprise-picture-added.1497459/
https://www.bladeforums.com/threads/harnds-talisman-my-attempt-to-like-ball-bearings.1480660/
https://www.bladeforums.com/threads/ch-knives-ch-3504-wow.1510700/
https://www.bladeforums.com/threads...ybe-not-so-much-now-opinion-changing.1466930/
This was a rather inflammatory post and triggered some rather negative reactions towards me. I have no problems with people disagreeing with me. I can be an idiot. Some are just attacking and some have valid points. Since then I have purchased three ball bearing knives and have come to a different conclusion, but not entirely in support of ball bearings in pivots. I promised to post my opinion after experiencing ball bearing knives after some use. Here is my updated opinion.
I now have 2 Harnds Talismon knives, 2 CH Knives CH3001 knives, and one CH Knives CH3504. There is a reason I have 2 of each of the former. I only have one of the CH3504 because it is only the most recent. I like all of them. All my other knives are washer type pivots with different materials.
There are many uses for knives. These uses can range from flipping at your desk for fun to survival use in the harsh elements. Some knives are clearly made for one extreme and others are made for the other. Folders are not the best use for survival situations and fixed blades are not the best for fun factor at the desk. There are always compromises. Always.
Bearings have been designed and refined over the decades according to their application. In general, plain (washer or bronze) bearings are applicable to slow speeds and high forces. Ball bearings are generally applied to higher speeds and lower forces. Plain bearings are generally better with static loads too. Knives mainly face static loads. If you are imposing a static load on a ball bearing it will have a much lower capacity than a plain bearing. The main benefit to ball or roller bearings is less friction at high speeds and in general.
It is hard to make a plain bearing that is permanently lubricated and sealed. This will have high friction and stiction. Ball bearings can be made that are sealed and lubricated for "life". This makes ball bearings more suitable for more variable conditions. High load static loads require the use of plain bearings over ball bearings. Remember? Compromise.
So how does this relate to knife pivots? There are conflicting requirements for knife pivots. Ideally they should be as friction free as possible, but also withstand possible high static loads without damage. These are conflicting requirements for both types of bearings. Which is best? It depends....
A plain bearing knife (washers) seems to hold the edge in low speed high force uses, such as in a knife. A plain bearing is seemingly less susceptible to easy contamination of the bearing surface if adjusted and lubricated properly. A plain bearing also seems to be more sensitive to adjustment of the pivot tightness, and to proper lubrication. A plain bearing knife will degrade very quickly with contamination of the lubricant between the bearing surfaces. This will mean disassembly, cleaning and lubrication. However it is extremely difficult to overload a plain bearing. No damage will result.
A ball bearing knife has the edge in low friction and ease of opening and closing. It has a deficit in handling high forces depending on the design. Depending on the bearing surfaces there could be problems with wear and brinelling. The best examples with hard balls against softer surfaces like titanium. One can get depressions in specific spots from large forces in one spot, tracks that get deeper over time, or pieces spalling out from repeated fractures from repeated movement and forces. If a knife has a hard surface for the balls to roll on then this is almost no problem. Ball bearings are also more exposed to contamination as almost every ball bearing knife has no seals to exclude contamination. This allows the contaminant to enter without impediment. This is a bigger problem for knives without hard surfaces for the balls to roll over. The benefit is that if there is a hard surface for the balls, the balls will just push the contaminant out of the way or just crush into non-importance. Because the bearing is open it is also easier to clean out the contaminant without disassembly. Flush, lubricate and move on.
IMHO, a knife with plain bearing system is superior for situations where there is never a chance of being able to clean or have access to flowing water or other cleaner, disassembly and reassembly. Tolerances will not change much and the opening and closing of the blade might get more difficult but it will not get so loose so as to cause a problem with lockup and safety.
On the other hand, ball bearing knives are superior if there are hardened steel washers for the bearings to ride on, that is if there are possibilities to clean any contamination from the pivot with water or some other liquid. Lubrication is much a less of a worry with ball bearings. If the bearing surface includes a soft surface like titanium, then cleaning , lubrication and adjustment seem to be a continuing concern. IMHO ball bearing knives that rely on titanium for their bearing surfaces should be considered light duty EDC knives and should not be relied upon for for your lost in the wilderness survival knife if SHTF.
Given my time with the knives I have listed as owning with ball bearings I would feel comfortable with each them as my only knife under the following circumstances respectively.
Harnds Talisman: Liner lock, AUS8, ceramic ball bearings on SS liners. I would feel comfortable with it as my only knife in any situation, but the onlooking public might find it scary. The AUS8 steel is a bit soft but easy to sharpen. The action is smooth and seems to withstand a bit of contamination.
CH Knives CH3001: Titanium frame lock, D2 steel, ceramic ball bearings against the titanium. This is probably my ultimate EDC, as in carry it anywhere. It is a big enough blade that I don't feel I am leaving capability at home. It is also much less scary for the public, and almost elegant. The problem is with this if I get lost in the woods it will last for a while but experiences has shown me that the ball tracks will get deeper in the titanium and make it unsafe after some period of time if I don't have the tools to correct it.
CH Knives CH3504: Titanium frame lock, ceramic ball bearings against hardened SS washers. This is a knife I would trust to not let me down in almost any situation where a folder would be sufficient, or even beyond. The bearings will not lose adjustment over time thanks to the hardened steel washers. Therefore the action will not die completely and the lockup should not suffer regardless of the contamination of the bearings and wear.
Conclusion:
My first rant on ball bearings was partially justified from my experience and knowledge, especially if the bearing surface is something soft like titanium. My first rant was also a bit biased. I feel that I am still correct about ball bearings in hard use knives, in that they are not the best design choice. But, in all practicality, my CH Knives CH3504 with ball bearings and hardened ball washers is a good compromise between ease of use, good feel, and durability. Ball bearings are not all bad but against bare titanium they should be mostly for light use. Ball bearings can be implemented in a good way, but one needs to be careful about what you buy and for what use.
Reference threads for the knives:
https://www.bladeforums.com/threads/ch-knives-ch3001-a-surprise-picture-added.1497459/
https://www.bladeforums.com/threads/harnds-talisman-my-attempt-to-like-ball-bearings.1480660/
https://www.bladeforums.com/threads/ch-knives-ch-3504-wow.1510700/
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