More about the Spyderco UF stone. Good stuff.

[subtropicsydney]

I've tried briefly to find some of the old information I once read about turning fine stones into ultra-fine stones through lapping them on a diamond stone and even though I'm asking "post-need" (explained later) I'm still wondering about a few things.

From memory I learned (maybe I've made this up with time) that it is inevitable that your fine stone through lapping will be turned ultra-fine: is that true? Does it depend on whether you use silicon-carbide powder or a diamond plate?

Whether or not that's the case what is the best way to re-condition a fine stone so it remains fine? As I said I'm asking after I need the info as I wanted to "refresh" my fine stone and eventually I just got out a relatively cheap 300grit diamond plate and went away.

I believe I flattened the stone a bit more and I've removed over 99% of the previous surface which was full of sharpening scratches and previous resurfacing attempts. It still seems "grabby", perhaps more so then before, and it's definitely whiter. Sort of quells my suspicion in turning a fine to an ultra-fine. Touched up two knives and it sounds alright. So then, what is it that turns a fine to an ultra-fine? Overall time spent? Grit?

BTW I'm not trying to advocate grit conversions on spyderco stones; and I'd much rather buy an ultra-fine than change a fine.

Talking about product line-ups: I think I can understand why the spyderco abrasive files of different shapes come only in fine, but it would be nice if medium was an option for some of them. How are you meant to do the course work for the job at hand? Go to Norton for their files I guess..?

[jackknifeh]

I've tried briefly to find some of the old information I once read about turning fine stones into ultra-fine stones through lapping them on a diamond stone and even though I'm asking "post-need" (explained later) I'm still wondering about a few things.

From memory I learned (maybe I've made this up with time) that it is inevitable that your fine stone through lapping will be turned ultra-fine: is that true? Does it depend on whether you use silicon-carbide powder or a diamond plate?

Whether or not that's the case what is the best way to re-condition a fine stone so it remains fine? As I said I'm asking after I need the info as I wanted to "refresh" my fine stone and eventually I just got out a relatively cheap 300grit diamond plate and went away.

I believe I flattened the stone a bit more and I've removed over 99% of the previous surface which was full of sharpening scratches and previous resurfacing attempts. It still seems "grabby", perhaps more so then before, and it's definitely whiter. Sort of quells my suspicion in turning a fine to an ultra-fine. Touched up two knives and it sounds alright. So then, what is it that turns a fine to an ultra-fine? Overall time spent? Grit?

BTW I'm not trying to advocate grit conversions on spyderco stones; and I'd much rather buy an ultra-fine than change a fine.

Talking about product line-ups: I think I can understand why the spyderco abrasive files of different shapes come only in fine, but it would be nice if medium was an option for some of them. How are you meant to do the course work for the job at hand? Go to Norton for their files I guess..?

I don't think you can change a fine grit ceramic stone into an ultra-fine grit. I'm counting on my memory also so take that for what's it worth (not a whole lot :) ) but I think the fine and ultra-fine stones start out the same but it's during the heating process of manufacturing that will determine the grit. Leaving the stone in the stove longer maybe? Hotter temperature maybe? I've also read where people have lapped their ceramic stones but I don't think it's recommended at all. Not that you will damage the stone essentially but it is NOT supposed to be necessary. Every Spyderco stone (fine & UF only) I've ever bought has been flat and needed no flattening. I checked them using a metal ruler that is known to have straight edges. The best way to test for flatness that I've used is to mark up my water stones with a pencil. When I lap them I know they are flat when all the pencil marks are gone. Or you can just go by the coloration. There have been discussions and pictures of examples of Spyderco stones that aren't flat. If I got one that wasn't flat I'd return it. Also keep in mind that ceramic is about as hard as a stone or knife blade can be. Even the ceramic knife blades absolutely need good quality diamond stones to sharpen them. Therefore, flatting or lapping them successfully is questionable. I don't really know any more that this about ceramic stones that need work. But I don't think you can change the grit at all. For any info on that I'd contact Spyderco's customer service. Pretty sure anything you try would void the warranty though but ask them that also. Good luck.

Jack

[subtropicsydney]

I'll just reiterate again; I'm not interested in changing my fine stone and I understand that fine and ultra-fine stones maintain their flatness well thus not needing lapping. I believe it's a personal thing in terms of lapping spyderco fine stones (NB strictly talking about F stones here). And when I say that my stone is probably flatter now what I mean is: "it was 'flat enough' to begin with, especially for my purposes". My aim in lapping was not to achieve flatness but to resurface the stone.

BTW what I've read is that the UF is an F but UF has a differently ground surface.

Reading a bit more I've found that I'm just digging and poking at the same old topics... Keeping a fine fine is all I've been after... hopefully I achieved that...

[subtropicsydney]

..is [it] inevitable that your fine stone through lapping will be turned ultra-fine: is that true? Does it depend on whether you use silicon-carbide powder or a diamond plate? ... So then, what is it that turns a fine to an ultra-fine? Overall time spent? Grit?

Found the answers to all of that now. But IMO you've got to piece together all the info and experiences out there to learn something.

Better question now would be about the best way to resurface (if one wanted to lap) to keep a similar "cut rate" and "finish pattern" to the original factory finish.

Just throwing it out there, not really asking/wanting a reply.

[northvanbamboo]

Today I have lapped one side of my Spyderco UF stone with Veritas 90grit SiC powder on glass.

The difference is staggering!
I am very pleased, it is cutting definitely more aggressive than the factory side.

My Sage5 LW got screaming sharp in less than 5minutes, stropped with green compound leather.

Great stuff indeed :)

[JD Spydo]

Today I have lapped one side of my Spyderco UF stone with Veritas 90grit SiC powder on glass.

The difference is staggering!
I am very pleased, it is cutting definitely more aggressive than the factory side.

My Sage5 LW got screaming sharp in less than 5minutes, stropped with green compound leather.

Great stuff indeed :)

I find your results incredibly interesting. Now how do you think this modified Spyderco UF stone would make a difference in performance like with sharpening a straight razor or to put a super fine edge on one of the Supersteel blades i.e. M390, 204P, ZDP-189 ect. It sounds like this modified stone surface would be something I would like to try for my M390 Military model. That M390 really takes a great edge when using the Ultra-Fine 302 Benchstone as it is.

[Zive]

Today I have lapped one side of my Spyderco UF stone with Veritas 90grit SiC powder on glass.

The difference is staggering!
I am very pleased, it is cutting definitely more aggressive than the factory side.

My Sage5 LW got screaming sharp in less than 5minutes, stropped with green compound leather.

Great stuff indeed :)

Thanks for sharing your results. Pretty cool experiment.

I would expect the side you lapped to behave essentially like a fine stone. I believe Sal has mentioned that the UF is essentially a Fine stone but lapped with a high grit abrasive to achieve a high grit finish. I wonder if lapping with a low grit would just undo the UF finish and leave you with a fine stone.

How do edges compare between finishing with the fine stone vs finishing with your lapped UF?

[FK]

This latest discussion on modified UF stone calls for some photos with the digital microscope units.
Both of the stone surface and knife bevel.

I agree the UF surface was roughed up to fine or medium surface with the improved sharpening times. The UF would take a very long time to restore an edge that quickly.

Regards,
FK

[JacksonKnives]

...
Now how do you think this modified Spyderco UF stone would make a difference in performance like with sharpening a straight razor or to put a super fine edge on one of the Supersteel blades i.e. M390, 204P, ZDP-189 ect.
...

Straight razor users often lap the UF stone to achieve flatness when carefully restoring an edge to tight tolerances of straightness, but IMO that in and of itself does not matter for sharpening a knife with any amount of belly.

If you play around with finishes you could probably tweak the scratch pattern to integrate the F or UF stone into a sharpening progression with other abrasives, but they make a good system as-is.

I find the ceramics load up very quickly and take a long time to do any significant sharpening after a few sessions. Cleaning my UF stone well (I have been happy with a caustic detergent I have in the shop designed for aluminum trailers, but barkeeper's friend should be similar) always makes me happy to use it again if I start to get frustrated.

[northvanbamboo]

Thanks for your suggestion, I've used simple 20x-40x microscope to take some pics for you.

Great idea as it revealed something I had been unaware of, it appears some of the lapping grit stayed bonded in the UF stone, mind you the stone was cleaned with BKF about 3 times after lapping and has been rinsed throughly number of times.

There is visible black dots that must be the remnants of lapping grit. Does this mean my UF stone is ceramic/SiC combo stone now? That explains why it cut faster than the factory side.

My bevels are not great and I have long way to go to get them straight, nice and clean. This is Sage5lw in CPM S30V steel.

[FK]

Yes, the black particles are SiC however, they are most likely much finer than when started. The distribution is very small and I believe would not contribute much to actual sharpening time. The SiC contamination does result in deeper scratches on the bevel.

Regards,
FK

[sal]

Good stuff, thanx.

sal