PB washers for BM 735

B

bomtek44

Joined
Apr 5, 2004
Messages
46
Greetings,

I want to order some PB washers for my new BM 735 from knifekits.com and need to know the diameter, and thickness, if someone could chime in.

Thank you,

bomtek44
 
the ones they have don't fit. I have had "some" success making my own from larger ones and making them fit through grinding and boring them out.

Best bet is to contact benchmade and beg them for a set or send the knife in and have them do it.
 
bomtek44, I have a BM710 with PB washers, and I think I preferred the Nylatron. If you want to do a straight swap - my PB washers for you nylatron ones, I'd be amenable. Please email me if you're interested.
 
what don't you like about PB? I can't think of a single detractor. Are you using militec?
 
PB needs lubricant to function which can trap dirt. Some synthetic washers need very little or no lubricant and are less likely to trap dirt. Some manufucturers and custom makers are quite adamant that some synthetics outperform the PB washers. I am not sure if nylatron is one of the materials.
 
PB is self lubricating, BUT add a little militec and you are set for months. Militec does not attract grit and dirt like some other lubricants - especially used in the miniscule amounts that are specified.
 
Nylatron is filled nylon polymer. I don't really have a complaint about phosphor bronze, I just like nylatron better, that's all. As far as I'm concerned, it's a superior material for washers. Metal-to-metal contact can have funky consequences in the right environment, almost regardless of which metals are involved. But then, I'm biased towards polymers anyway. Oh yeah, and they don't require lubrication, like brownshoe said. But it's mostly an unfounded bias, just like the preference for PB washers is.
 
I wouldn't call it unfounded. PB is a more stable material and as such will not deform or tear when taking a knife down and reassembling or for those that like the pivot tighter. There is a reason CRK and BM and now Spyderco and Kershaw are all using or moving towards PB in their high end models.
 
I meant unfounded as in of little or no practical value. If you're comparing phosphor bronze to CRKT-type soft Teflon washers, there's a practical benefit, because their Teflon washers are extremely easy to deform. Even that advantage, however, is questionable because most people will never realize they have a deformed washer until they remove it from the knife. As for stability, what variety are you referring to? Mechanically speaking, yes, phospher bronze will deform less easily than Nylatron. However, what is the practical difference? You mention disassembly and reassembly - this is a valid point, however in my experience the same lack of knowledge that might cause an amateur to "wedge" his washer in a way that causes deformation could easily do the same to a PB washer - he simply has to apply more force. Moreover, a deformed Nylatron washer is still perfectly serviceable as a washer, whereas a PB washer would probably need some minor repair (filing down of a "lip," etc.). Another concern might be that a Nylatron washer would deform under excessive pressure from the pivot screw. Living in NYC, I have tightened all my knives to a ridiculous degree. Not one of my Nylatron washers (generally in Benchmade knives) has shown any sign of deformation. As for chemical stability, PB, like all metals, can and does corrode. Not much, and generally not enough to be worth considering, but it does, and it's something that I'm more aware of than strength. Nylatron does not corrode, period. Lubricity is also an issue for me - I hate web lubricants because they attract dust. PB has high lubricity, but that is a feature of the sintering process that creates the metal and allows it to be impregnated with lubricant, not an inherent feature of the material itself, as is the case with Nylatron.

Ultimate strength, in my opinion, is only of importance if prying is something you do frequently. Nylatron has no trouble recovering from lateral forces that it would encounter during normal or heavy usage appropriate to a knife. However, PB would certainly outclass it in deformation resistance if heavy prying was done. However, in that case, I would be more concerned about the threads of the pivot screw and the handle material around the pivot than I would be about the washers.

Good point about the higher-end manufacturers using it in their pieces - however, I would imagine that the public outcry for PB washers on forums like this one had some sizable influence on that decision. CRK always did it - the bushing system in the Sebenza deals with different forces than the simple washer-tang-washer system in the production knives, so it makes sense for them. For the other companies, I'm inclined to believe it's more of a PR move than an actual, measurable upgrade in performance. Like I said, I have nothing against phospher bronze and would certainly take it over a number of candidate materials. It's just that Nylatron, in my opinion, is superior as a material for washers.

(*Whew* was that long enough for you?)
 
Emerson has used Nylatron since the beginning. I went to a lot of trouble to get a set of Phosphor Bronze washers for my CQC-8 for testing. I found no particular improvement over Nylatron except they provide a slight degree of extra stiffness when prying. I gave away the PB washers and put the Nylatrons back in. The Emerson washers are big, 0.255 ID and run 0.032 thick with OD's from 0.500 to 0.625 depending on the knife. IMHO I see no real need for PB.

That said, if one or more of you decided to go to Boker USA and have custom PB washers made (min order is usually about 100) for the more popular folders, you could probably make a 500% profit selling "washer upgrade kits".
 
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