The "WHY" of the Bushing Pivot?

[enduraguy]

I was thinking about this earlier. I have owned many Spyderco folders over the years. "Pinned" together models like the steel handled Police and classic Delica and Endura models. I have also owned "screw together" models such as the Police 3, Para 1 and Military. None every gave me any problems what so ever. Lock ups were always solid. I understand a pinned together knife can lose some tolerance after a lot of use in the pivot area and develop some slight play. I just don't "get it" though with the bushing pivot. Why was it "needed"? I'm not criticizing the pivot, or Spyderco. I'm just trying to better understand why it was developed. Surely, it was a pretty penny per se in tooling and R&D. I do not believe Spyderco would bring it about just to cater to a very small percentage of their buyer market who like to "flick" open their folding knives, yet keep a solid lockup. Well, even lockup with this pivot is debatable. Some report slight side to side wiggle and some do not. My sample Para 2 does have slight side to side, even with the pivot and other screws tight as can be....but as the knife has grown on me over the last few months...that does not bother me. Even though my Military has zero blade play with it's "classic" pivot.

Sal, anyone? Thanks.

[chuck_roxas45]

Yep, I wondered that too. Made me hold off on the para 2 for some time.

[Boberama]

I like it in principle but I'm holding off buying a knife with one because of the gravity knife laws here. I can flick out most knives before I adjust them and I don't feel comfortable carrying something that is technically illegal. If not for those pesky laws I think I'd be totally fine with it.

[acer]

A good question.

[sal]

Hi Enduraguy,

Positives include: "Optimal" tightness on blade, less "feel" type of adjustment in assembly. Negatives include: very close tolerances required to make them, inability of some customers to make their blades tighter. We're still deciding on whether or not to continue to use them.

sal

[The Deacon]

First off, Spyderco doesn't really use a bushed pivot. They do use a stepped pivot on some models. As for the why of bushed pivots, it's probably mostly a PR thing. Bushings make sense as cheap, expendable, parts used to save wear on expensive parts - crankshaft/engine block crankshaft/con rod con rod/piston. On a knife, they don't really do that. Their claimed advantage is allowing the pivot screws to be socked down dead tight, but that can be accomplished with a stepped pivot or a chicago screw pivot, because in all cases it's really just a question of getting the lengths exactly right.

[Blerv]

Just a guess, most changes having to do with manufacturing are done to benefit the company's ability to manufacture and maintain it's standards. Since Spyderco's standards aren't based on penny-pinching I have to think they deem it a superior design for most its targeted demographic.

In the case of pinned pivots it was likely what the makers were accustomed to and has worked for a long time. The change to a screwed pivot would have been against the grain which often means expensive or a hassle. Since the average user (back then) would likely not care or notice people have been pinning knives for a long time.

Screwed pivots allow for easier maintenance/repair for the company. Spyderco has said it is cheaper to make knives in this fashion, likely because on the assembly level a knife can be easier to dial-in for the end user. Our ability to tighten or loosen the action (or even disassembly) is a happy bi-product of the design.

The latest system allows the maker to fully tighten the pivot without impacting the action. In a way this increases the chances that a Spyderco's is operating in an acceptable range. It attempts to separate the two features so both can be ideal.

As for blade play, even grinds, and centered blades. Many of these are subjective per user and often have no bearing on performance. Nonetheless they can be aesthetically displeasing and even disconcerting. If you can get past the tactile feedback and looks most knife problems aren't problems at all.


EDIT: Sometime between the start and end of this little dissertation Sal chimed in with exact info. :o

[Fred Sanford]

Just my $.02

I don't care for the bushed/stepped pivot on the Manix 2, Yojimbo 2, and Para 2.

I like my knives to be a bit tighter and I cannot tighten them down to the point that I usually like.

It's a very small gripe but I would just like to throw it in the hat with the rest.

Some of the longest lasting knives I own are pinned and they still have no play.

[Slash]

Cause people care about the blade to have perfect centering. All my crk knives are centered. Also they have zero blade play, closed or opened.

[APS]

I too wish I was able to tighten the pivot of my Yo2 and PM2 a little more to increase closed blade retention with tip up carry.

[jujigatame]

Maybe the one component wasn't necessarily "needed" in the strictest sense of the word but Spyderco felt the need to try it and see what the benefits and drawbacks would be on a large scale with end users.

[jackknifeh]

I'm not familiar with bushings, stepped pivots, etc. I have never had any problems with any Spyderco pivots that were pinned. In fact my first was an Endura3. The thing opened/closed so perfect with no blade play I was amazed. All other pinned pivots were the same. Having said that I want pivots with a screw in every knife I own. Even though it won't always be necessary I like being able to adjust it to my liking. If a Spyderco knife I want has a pinned pivot I will buy it but will wish it had a screw. :) The Centofante for example has been in my sights for a long time.


Jack

[JimP]

The examples of bushed pivots I have been able to get my hands on, I really like, but it makes them difficult for me to import, which is a big negative for us Spydie fans with tight laws.

[Boberama]

The examples of bushed pivots I have been able to get my hands on, I really like, but it makes them difficult for me to import, which is a big negative for us Spydie fans with tight laws.

^Yes, that is true, but it's not just the importing I worry about, once it's in the country and in my hands I like it to stay legal... that's another reason why I don't like pinned pivots, I have an old loose pinned knife and I can't adjust it without a lot of work.

[Evil D]

I'm torn. On one hand, i love the silky smooth almost zero resistance pivots that they "bushing" gives you. My Para 2 and Yojimbo 2 open so smooth it's ridiculous. On the other hand, they both have a little side to side play that developed just a week or so after medium-hard use. None of my Para 2's could be adjusted back to that point again to completely eliminate the side to side play. My 20CP Para 2 is completely tightened all the way down and still has side to side play. By comparison, my Centofante 4 has a pinned pivot that opens smooth but with noticeably more resistance, doesn't fall closed by gravity but it has absolutely no play in any direction after tons of use, and it only has one liner and no bushing of any kind. The more pieces you introduce, the more important tolerances become between all those pieces. The more pieces rub together, the more friction you have, the more parts you have that wear, and the more potential play could result.

[Orion's Belt]

I like the stepped pivot. I've gotten both of my Para 2s and both Manix 2s to the point of a free-falling blade with zero play. I will admit, some tinkering was involved, though.

[enduraguy]

Yea, my Para 2 is a user as well. Anyone else who uses their knives seen side to side play develop?

[Roundabout136]

I like the stepped pivot. I've gotten both of my Para 2s and both Manix 2s to the point of a free-falling blade with zero play. I will admit, some tinkering was involved, though.

I've been tinkering with mine for what feels like once a month for a year. Can't get it 100% perfect. Ticks me off just a tiny bit.

I've even semi-polished the liner and bushings, just can't get it perfect.

[Evil D]

Yea, my Para 2 is a user as well. Anyone else who uses their knives seen side to side play develop?

Yep, on all 3 of my Para 2s. All of them were perfect out of the box, all developed play within the first month of use.

[DeathBySnooSnoo]

Hi Enduraguy,

Positives include: "Optimal" tightness on blade, less "feel" type of adjustment in assembly. Negatives include: very close tolerances required to make them, inability of some customers to make their blades tighter. We're still deciding on whether or not to continue to use them.

sal

I for one hope that you keep the stepped pivot. I really like the smooth feel and the fact that you can easily make adjustments. As long as there is a good strong detent to the knife then I know that up here where "flick" knives are not legal things are ok.