Finest hones?

C

colrich999

Joined
Jul 29, 2003
Messages
4
I am trying to achieve the most polished edges possible .(I am aware that these are not ideal for many uses and that blade thickness and geometry etc are all critical).
What are the finest hones available?
The shapton site has 15000 grit and even 30000 grit hones listed, anyone tried these?
What do these equate to in microns?
Are these better than the latest coated abrasives?- I just took delivery of some mylar backed 0.3 micron lapping film.
I sharpened my SAK on my SKARB system finishing with a spyderco ultra fine ceramic stone then the polishing film and the results, so far, are impressive!
 
Hello, and welcome to the forums!

Check this link for some info: http://www.ameritech.net/users/knives/index.htm

I would think that the shaptons would be the finest synthetic stones. I use buffing compound and a strop and I believe the compound would be about half or 1 micron thick. I'm not sure if you can go much finer than .3 microns! I certainly naven't heard od much, but I bet Cliff Stamp on this board would know better than I.

By the way, click on the E and F sections forst on that sharpenign site. The F section has a chart showign abrasives vs. speed of cutting, very interesting. The E section compares the stones with respect to grit size. That one will be of interest to you. Shoot Shapton an e-mail and ask them in micron size how small you can go!

Good luck.
 
I have an antique two-sided whetstone I got at a yard sale for a couple bucks. It's like new. It belonged to a guy's grandfather who was a barber and he used it for straight razors and that's what it was made for. This stone, to feel it, you can't believe it's a whetstone. It feels like smooth marble. But it puts an edge on a straight razor that once you follow up with a strop, it gives you the best shave bar none. You can probably still find these stones at a real barber's supply store.
 
The Shapton #15000 ceramic stone is ~1 micron (~120$), the #30000 is finer, ~0.5 micron you would assume, I have not seen its specifics. It is decently expensive, $595. CrO paste is ~0.5 micron and a lot cheaper.

Lee used CrO lapping compound as the final step in sharpening plane blades and the polish was so fine that the edge was almost perfectly smooth, even with a resolution better than a micron. This was much sharper for example than a Wilkinson Sword razor blade.

I have used CrO on mylar and it cuts faster than CrO on leather, and can give a finer finish as it isn't irregular like leather loading can be.

http://www.shaptonstones.com/stones/Professional-Series.php

As a side note on the Shapton stones, they are not ceramic in the traditional sense, they need to be lapped. Some reading on the site seems to indicate a decent amount of knowledge about various blade materials, the high loading rate of japanese chisels due to the iron in the laminate for example. Interesting stones, though very expensive compared to synthetic Japanese waterstones.

-Cliff
 
www.toolsforworkingwood.com sells .5 micron and .3 micron lapping film. .3 micron lapping film (mylar backed like the stuff Lee sells) on a sheet of plexiglass is probably the finest hone you can find in terms of grit size and cost (less than $2 per sheet).
 
As a side note on really fine abrasives, these have been looked at in detail in the wood working newsgroup on usenet. When you get to really high polishes, the surface of the edge can be dominated by the grain structure and carbide makeup of the steel. D2 for example would not be suitable for such high honing due to the large aggregated carbides. If you want to look at very high polishes go for simple steels with a fine grain structure and well distributed carbides like 52100.

-Cliff
 
Cliff,

I am assuming that some of the powder metallurgy steels would be ideal then when going for a super polished edge, given the homogeneity and such? Also, is the CrO you use the fine stuff from Lee Valley?
 
Crayola,

S30V takes a beautifully sharp edge with Spyderco's ultra-fine hones, better than D2 in my new-to-sharpening hands, so I'd imagine that it and the other V's would all benefit from high-grit finishes.
 
thrombrogoran, thanks for the link! Right now I polish using Mibro brand polishing compound sticks applied to a manila folder with a hard surface backing it. It works pretty well, but I'm sure I could do better with something a bit more consistent.
 
I use the spydie whites and veritas green (0.5micron CrO paste) for my edges.

The ats-55 ss dragonfly I have been beating on for 2yrs(and redid the edge angle a few times) is holding an edge for a month now without touching it to the strop or a steel.

Have it down to about 20deg(might be a bit under), do my sharpening about 4-5deg off the flats now, so I could go smaller now that this holds. I sharpened on 1200grit sandpaper, cleaned that up on the whites, and then the strop. It shaves right now, but I gave it a couple swipes on my jeans last week to fix the wire up(left a little bit on, next sharpening/thinning I'll make more effort to get it off). All freehand...

This thing is pretty much a scalpel. When I need to touch up my temperance fixed, I'll be doing the sandpaper and strop on it too.
 
thombrogan,

Thanks for that information. I figured that the homogeneity of the particle metallurgy process would lend itself well to polished edges(earlier I said powder, but I meant particle. Though powdered steel may be the same). However, grain size and the actual make-up of the steel would be important too. Large carbides versus small carbides, etc. all would play a part. I look forward to getting an S30V blade someday to test these things out.
 
You can get an S30V Native for around $50 online. They're awesome with any steel type and S30V just makes them better.

Roadrunner,

If you try using the lapping film on the hard backing, let me know how it works out for you.
 
The CPM process does allow for a very fine grain and ultra low carbide segregation, both of which seem ideal for highly polished edges. However the current grades of steel offered like S30V are many times more coarse than alloys like 52100 which can have grain sizes of less than a micron which very fine carbides.

This problem of steel characteristics influencing sharpness is also one in which you will only ever notice a problem if the edge angle is quite low. The steels that I noticied it in had edge angles of significantly less than 10 degrees, in them you could then see the edge breaking apart as it was finely honed and no polishing could improve it.

Even the very coarse steels like D2 which also have massive carbides (more than ten times larger) have no problems in achieving a vert high polish once the angles start to become more obtuse. The custom I have from Mel Sorg came with a finish that easily push cut straight down into fine newsprint and could easily push shave hair above the skin.

Yes I use the CrO bar from Lee Valley, that is also where I got the CrO on mylar abrasive.

-Cliff
 
Cliff,

Could the "problem" of big, blocky carbides and nitrides be solved by putting a relatively thicker microbevel on the edge and polishing that? I have a Benchmade Switchback with a 40 degree micro bevel and a Spyderco Native with a 30 degree microbevel and they're both very sharp feeling and smooth on an EdgeTester.
 
Thanks for the info Cliff! Is it the vanadium content in the CPM steels that is responsible for the large carbides, which makes for a grain size that isn't as small as something like 52100? Is there a CPM steel that has a very fine grain like 52100?
 
Actually, I think Crucible sells some AISI 52100, but it's not made with particle metallurgy goodness.

I think there's some section in a long forgotten holy book that says to get a knife made from Crucible's M2 so that you may be happy for generations to come.

I'd say get a hold of some .5 micron and .3 micron lapping film sheets (the backing is more rough feeling than the abrasive side) and some .5 micron CrO buffing compound and make the best of it.
 
how sharp will those stones make the blade? or is it just a matter of the finish left behind?
 
mlawson,

there are 2 main elements to sharpness, geometry and finish. On a felling axe, you want a convex edge that is still kinda thin for penetration and strength. You couple that with a polished finish so that you get maximum edge retention, better fibre severing and penetration. On a rope cutting blade, you'd want somethign maybe a bit thicker to handle tough rope, and then you'd want a coarser finish so that you have microteeth to help slice rope.

So, the Shapton stones in the high grits won't change the geometry so much as they will change the polish. However, super fine hones aren't all that good unless you are good with the stones in your rougher grits. When going for a perfect high polish edge, you don't do well if your edge bevel is wobbly and you have 1200 grit waterstone scratches in that 15000 grit shapton finish!
 
I am new to this forum but not to sharpening.
When I want a highly polished edge, I work up in grit sizes till 0.5 micron green mylar.
For example on the picture below, the polish is at 17 deg.

Then I can put a tiny micro bevel ( the edge ) using a coarse grit
to give me the required edge for the work at hand.

The overall effect is a polished edge unless you look very close.
The picture shows the micro edge in the process of being applied at 19 deg.

All this is quite easy with an Edge Pro sharpener.
fb84b2f3.jpg
 
now try doing it all freehand...

my calypso jr has a 20deg(inclusive) bevel(on spyderco whites), and 30deg(inclusive) working edge on a 800 grit stone.

I only use my 204 for serrated edges, everything else is freehand. been doing freehand for 14yrs.
 
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