Polishing Washers

Discuss Spyderco's products and history.
User avatar
toocool006
Member
Posts: 336
Joined: Mon Nov 06, 2017 4:42 pm
Location: New Orleans

Polishing Washers

Postby toocool006 » Tue Jan 22, 2019 9:22 pm

I've read quite a few posts here and elsewhere about folks polishing up PB washers for slicker action. What tools are typically used to do the polishing? It would make me nervous to remove material from the washers given the exacting tolerances at play. Thanks for any input y'all can provide!
~andrew

User avatar
abbazaba
Member
Posts: 3370
Joined: Mon Nov 09, 2015 3:40 pm
Location: New England

Re: Polishing Washers

Postby abbazaba » Tue Jan 22, 2019 9:40 pm

I've used 1500 grit and 3000 grit automotive sand paper with success many many times. Lay the sand paper on a flat surface and polish each side by moving the washer small circles with light pressure as evenly as possible with your finger until all of the tarnish has been removed. This is when any dishing or raised edge of the washer will be exposed in the tarnish.

Then just clean with alcohol and put a dab of nano lube during reassembly. This is also a good time to inspect the inside of the knife for burrs and uneven wear marks that can sometimes benefit from some light sanding.

In my experience you'd have to really go crazy to screw it up. Washers are cheap if you do somehow ruin one. There is probably a video or two out there as well.

User avatar
anycal
Member
Posts: 1594
Joined: Wed Jan 11, 2017 12:40 pm
Location: California

Re: Polishing Washers

Postby anycal » Tue Jan 22, 2019 9:48 pm

I rub mine on ultra-fine tri-angle stone (or any fine stone), index finger on top of washer, rotating it once in a while. Not too long, not too much pressure. I can see spots where the washer took a polish.
Last edited by anycal on Tue Jan 22, 2019 9:50 pm, edited 1 time in total.
Peter

User avatar
toocool006
Member
Posts: 336
Joined: Mon Nov 06, 2017 4:42 pm
Location: New Orleans

Re: Polishing Washers

Postby toocool006 » Tue Jan 22, 2019 9:50 pm

abbazaba wrote:
Tue Jan 22, 2019 9:40 pm
I've used 1500 grit and 3000 grit automotive sand paper with success many many times. Lay the sand paper on a flat surface and polish each side by moving the washer small circles with light pressure as evenly as possible with your finger until all of the tarnish has been removed. This is when any dishing or raised edge of the washer will be exposed in the tarnish.

Then just clean with alcohol and put a dab of nano lube during reassembly. This is also a good time to inspect the inside of the knife for burrs and uneven wear marks that can sometimes benefit from some light sanding.

In my experience you'd have to really go crazy to screw it up. Washers are cheap if you do somehow ruin one. There is probably a video or two out there as well.
Thanks for the pointers, Ian!
~andrew

User avatar
toocool006
Member
Posts: 336
Joined: Mon Nov 06, 2017 4:42 pm
Location: New Orleans

Re: Polishing Washers

Postby toocool006 » Tue Jan 22, 2019 9:51 pm

anycal wrote:
Tue Jan 22, 2019 9:48 pm
I rub mine on ultra-fine tri-angle stone (or any fine stone), index finger on top of washer, rotating it once in a while. Not too long, not too much pressure. I can see spots where the washer took a polish.
This sounds like a great method too, thanks Peter!
~andrew

User avatar
toxophilus
Member
Posts: 586
Joined: Tue Feb 10, 2015 4:07 pm
Location: Colorado; Earth

Re: Polishing Washers

Postby toxophilus » Tue Jan 22, 2019 9:57 pm

I use a partially cracked Chosera 10,000 grit stone from my Edge Pro, a few drops of oil and use a circular motion till it's nice & shiny; remember you're 'polishing', not removing metal... sorta like polishing the finish on a car :spyder:

User avatar
Bloke
Member
Posts: 4720
Joined: Fri May 13, 2016 12:43 am
Location: Sydney, Australia.

Re: Polishing Washers

Postby Bloke » Tue Jan 22, 2019 11:11 pm

toxophilus wrote:
Tue Jan 22, 2019 9:57 pm
... sorta like polishing the finish on a car :spyder:
Image
A day without laughter is a day wasted. ~ Charlie Chaplin

crazywednesday
Member
Posts: 572
Joined: Tue Jun 27, 2017 8:32 am
Location: Pacific Northwest

Re: Polishing Washers

Postby crazywednesday » Tue Jan 22, 2019 11:49 pm

anycal wrote:
Tue Jan 22, 2019 9:48 pm
I rub mine on ultra-fine tri-angle stone (or any fine stone), index finger on top of washer, rotating it once in a while. Not too long, not too much pressure. I can see spots where the washer took a polish.
Exactly how I do it.
Justin

User avatar
JacksonKnives
Member
Posts: 763
Joined: Thu Jan 10, 2008 8:28 pm
Location: Formerly Alberta, now Orange County, California
Contact:

Re: Polishing Washers

Postby JacksonKnives » Wed Jan 23, 2019 12:01 am

One thing to remember with lapping bearing surfaces: once you knock down any obvious ridges or bumps, fit and thickness/flatness are far more important than smoothness. Binding/slop matters, finish doesn't. A polished surface and a marred surface have the same coefficient of friction, since the same amount of weight is borne per square inch of rubbing material either way. [edit: this is a bit of an inaccurate way to phrase the problem. See my clarification below.]

The holes or grooves you find in some washers/bushings will allow you to "store" grease/oil for longer-term dispersal, but the amount of friction is the same until you change the material or put in bearings.
Last edited by JacksonKnives on Wed Jan 23, 2019 12:44 pm, edited 1 time in total.

Daveho
Member
Posts: 1260
Joined: Tue Feb 20, 2018 9:19 pm

Re: Polishing Washers

Postby Daveho » Wed Jan 23, 2019 1:28 am

The tolerances arnt that tight here given that the pivot can simply be adjusted.
I have a dragons tongue stone I occasionally smooth a washer on but not all that often

User avatar
Pelagic
Member
Posts: 2440
Joined: Fri Apr 27, 2018 5:49 pm
Location: East Coast/Nomadic

Re: Polishing Washers

Postby Pelagic » Wed Jan 23, 2019 6:58 am

I use my wood strops loaded with compound plus diamond powder. Fast and easy.
Pancake wrote:
Wed Aug 14, 2019 10:20 pm
Are you a magician? :eek:
Nate wrote:
Thu Apr 04, 2019 4:32 pm
You're the lone wolf of truth howling into the winds of ignorance
Doeswhateveraspidercan wrote:
Sat Jun 15, 2019 9:17 pm
You are a nobody got it?

User avatar
ChrisinHove
Member
Posts: 2577
Joined: Tue Dec 17, 2013 8:12 am
Location: Thoroughly brassed off with 2020

Re: Polishing Washers

Postby ChrisinHove » Wed Jan 23, 2019 7:11 am

Rigid strop and blue compound for the washers. Cloth and compound for the mating surfaces.

freebird610
Member
Posts: 157
Joined: Sun Jun 19, 2016 11:13 am

Re: Polishing Washers

Postby freebird610 » Wed Jan 23, 2019 9:51 am

leather strop with green compound occasionally.

User avatar
toxophilus
Member
Posts: 586
Joined: Tue Feb 10, 2015 4:07 pm
Location: Colorado; Earth

Re: Polishing Washers

Postby toxophilus » Wed Jan 23, 2019 10:57 am

Bloke wrote:
Tue Jan 22, 2019 11:11 pm
toxophilus wrote:
Tue Jan 22, 2019 9:57 pm
... sorta like polishing the finish on a car :spyder:
Image
ROFLMFAO!!!

User avatar
toocool006
Member
Posts: 336
Joined: Mon Nov 06, 2017 4:42 pm
Location: New Orleans

Re: Polishing Washers

Postby toocool006 » Wed Jan 23, 2019 11:13 am

JacksonKnives wrote:
Wed Jan 23, 2019 12:01 am
One thing to remember with lapping bearing surfaces: fit and thickness/flatness are far more important than smoothness. Binding/slop matters, finish doesn't. A polished surface and a marred surface have the same coefficient of friction, since the same amount of weight is borne per square inch of rubbing material either way.
The holes or grooves you find in some washers/bushings will allow you to "store" grease/oil for longer-term dispersal, but the amount of friction is the same until you change the material or put in bearings.
This is really interesting. Is it possible that lapping (if done accurately) would bring some microscopic increase to the flatness of the surfaces in question?

I'm finding it hard to follow the argument that a marred surface has the same coefficient of friction - my sens is that there would be some amount of mico-binding vs a polished surface. Why isn't that so?
~andrew

User avatar
JacksonKnives
Member
Posts: 763
Joined: Thu Jan 10, 2008 8:28 pm
Location: Formerly Alberta, now Orange County, California
Contact:

Re: Polishing Washers

Postby JacksonKnives » Wed Jan 23, 2019 11:57 am

toocool006 wrote:
Wed Jan 23, 2019 11:13 am

This is really interesting. Is it possible that lapping (if done accurately) would bring some microscopic increase to the flatness of the surfaces in question?

I'm finding it hard to follow the argument that a marred surface has the same coefficient of friction - my sens is that there would be some amount of mico-binding vs a polished surface. Why isn't that so?
If you can make two surfaces truly flat to a molecular level, they actually stick together. Gauge blocks machinists use are actually pretty hard to get apart if you "ring" them together.

No doubt I'm forgetting something about the way friction and surface finish work out, but if you read the textbooks and other reference material they all have the same note.

*edit* I misspoke. I'm remembering something I read about perforated washers after investigating the advantages of CRK's design in the Sebenza

It's not accurate to say that "surface finish doesn't matter." Obviously, a badly-machined surface is going to cause more friction. But why?
Evenness is important. You don't want to machine in a way that will leave ridges that can interlock, but if nothing is binding then you're just left with the friction properties of the material.

So long as the peak, load-bearing surfaces are even and spread the same load over the same area, the amount of load per area over the surface of the washer is the same no matter what you try to do. If you cut holes in your washer, or add ribs, or do anything to reduce the contact surface, you're increasing the amount of force borne by those contact points and your design feature is cancelled.

Dirt and uneven ridges or bumps will obviously change the dynamics of the washer when it's moving, but once you get the washer flat it's hard to increase its efficiency. Once the surface has an even finish and there are no unusually high peaks on either side, you're just getting more and more microscopic peaks to bear the weight, which means more and more surface area rubbing.

Contrast polishing a slightly-uneven washer (with one point that's thicker than the rest of the washer) with compound to sanding that same slightly-uneven washer with 400-grit paper to get an even thickness. Making the surface area even means you're actually changing the contact area that rubs when you tighten the pivot. Polishing the washer can only very slightly improve the characteristics of the contact patch that's already rubbing.

In my actual experience with knives, the washers are rarely cupped or un-polished. They are, fairly often, bent enough to make two "sides" (e.g. 3 o'clock and 9 o'clock if you think of the washer as a clock face) bear more load on one side (and of course the opposite pattern on the other side.) The surface finish is almost always rougher on the knife blade, but the fact that the finishing lines are parallel on the knife (or, better yet, stonewashed) means it doesn't cause many problems. I feel that the knife is smoother if I can flatten the washer, but I know I'm almost always getting the same result with a good cleaning.

Also note that if you use any kind of lubrication, the effect of surface finish is basically nil. The residue left when your lube dries out is far more important than surface finish in that case.

User avatar
JacksonKnives
Member
Posts: 763
Joined: Thu Jan 10, 2008 8:28 pm
Location: Formerly Alberta, now Orange County, California
Contact:

Re: Polishing Washers

Postby JacksonKnives » Wed Jan 23, 2019 12:58 pm

Daveho wrote:
Wed Jan 23, 2019 1:28 am
The tolerances arnt that tight here given that the pivot can simply be adjusted.
I have a dragons tongue stone I occasionally smooth a washer on but not all that often
I actually agree with this, in principle, given that the washers as they come from the factory are pretty good. But many of us are chasing smoothness with zero blade play, so we try weird things to see what happens. :)

A precise fit of perfectly-even washers with perfectly-even mating surfaces on the blade means that you can adjust the amount of tension on the pivot screw until you hit the effective friction coefficient of the material. That should be, in theory, the best pivot smoothness you can achieve without bearings.

In my experience, though, the tension of handle screws (and sizing of spacers/standoffs and the holes they sit in) has almost as much influence on blade play and smoothness. You can't just assume that the scales/liners are mathematically flat parallel planes and blame all the binding on unpolished washers.

So, the tolerances aren't "tight" in terms of what we can achieve with lapping of washers, but the tolerances that influence how much blade play/friction we can perceive are *very* small.

User avatar
toocool006
Member
Posts: 336
Joined: Mon Nov 06, 2017 4:42 pm
Location: New Orleans

Re: Polishing Washers

Postby toocool006 » Wed Jan 23, 2019 3:41 pm

JacksonKnives wrote:
Wed Jan 23, 2019 11:57 am
toocool006 wrote:
Wed Jan 23, 2019 11:13 am

This is really interesting. Is it possible that lapping (if done accurately) would bring some microscopic increase to the flatness of the surfaces in question?

I'm finding it hard to follow the argument that a marred surface has the same coefficient of friction - my sens is that there would be some amount of mico-binding vs a polished surface. Why isn't that so?
If you can make two surfaces truly flat to a molecular level, they actually stick together. Gauge blocks machinists use are actually pretty hard to get apart if you "ring" them together.

No doubt I'm forgetting something about the way friction and surface finish work out, but if you read the textbooks and other reference material they all have the same note.

*edit* I misspoke. I'm remembering something I read about perforated washers after investigating the advantages of CRK's design in the Sebenza

It's not accurate to say that "surface finish doesn't matter." Obviously, a badly-machined surface is going to cause more friction. But why?
Evenness is important. You don't want to machine in a way that will leave ridges that can interlock, but if nothing is binding then you're just left with the friction properties of the material.

So long as the peak, load-bearing surfaces are even and spread the same load over the same area, the amount of load per area over the surface of the washer is the same no matter what you try to do. If you cut holes in your washer, or add ribs, or do anything to reduce the contact surface, you're increasing the amount of force borne by those contact points and your design feature is cancelled.

Dirt and uneven ridges or bumps will obviously change the dynamics of the washer when it's moving, but once you get the washer flat it's hard to increase its efficiency. Once the surface has an even finish and there are no unusually high peaks on either side, you're just getting more and more microscopic peaks to bear the weight, which means more and more surface area rubbing.

Contrast polishing a slightly-uneven washer (with one point that's thicker than the rest of the washer) with compound to sanding that same slightly-uneven washer with 400-grit paper to get an even thickness. Making the surface area even means you're actually changing the contact area that rubs when you tighten the pivot. Polishing the washer can only very slightly improve the characteristics of the contact patch that's already rubbing.

In my actual experience with knives, the washers are rarely cupped or un-polished. They are, fairly often, bent enough to make two "sides" (e.g. 3 o'clock and 9 o'clock if you think of the washer as a clock face) bear more load on one side (and of course the opposite pattern on the other side.) The surface finish is almost always rougher on the knife blade, but the fact that the finishing lines are parallel on the knife (or, better yet, stonewashed) means it doesn't cause many problems. I feel that the knife is smoother if I can flatten the washer, but I know I'm almost always getting the same result with a good cleaning.
Thanks for taking the time, this is very well explained and giving me a greater appreciation for and understanding of the levels of machining involved.

I googled Gauge Blocks (of which I was previously completely ignorant) to see the see the sticking together you described - https://www.youtube.com/watch?v=2lOOl3VxOtE - wow physics is so cool. What an amazing world we live in!
~andrew

User avatar
Evil D
Member
Posts: 22190
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: Polishing Washers

Postby Evil D » Wed Jan 23, 2019 4:32 pm

All the washers I've seen are fairly smooth, I'd look more into polishing the grind lines off the tang and polish the liners that contact the washers. Seems like that would yield better results.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
~David

User avatar
ChrisinHove
Member
Posts: 2577
Joined: Tue Dec 17, 2013 8:12 am
Location: Thoroughly brassed off with 2020

Re: Polishing Washers

Postby ChrisinHove » Thu Jan 24, 2019 1:26 am



Return to “Spyderco General Discussion”

Who is online

Users browsing this forum: Airlsee, Bing [Bot], cgjones, Google [Bot], Himark800, Humbbaby, jdw, MFlovejp, the74impala and 44 guests