sharpening with "loose" diamonds update

Bill, thanks for sharing your experiment

Ian N in Sydney

>

2 cents

Wiley Horne--Glendora CA

>Bill,

Great report as always! Here's my 2 cents, which bear out the points Bill has been making. I've not been at this long, so this is totally anecdotal.

Cast Iron. Ordered three 1-1/4 x 3-1/4 x 12" slabs from Metal Express. $23 and 13lb each, total from Waukesha, WI was about $100. They arrived big, heavy, black oxide covered, and crowned on top and bottom. Flattening was a mess--black grindings everywhere. Get out in the back yard with a belt sander and gloves. Don't put em on your reference plate with abrasive until they test quite flat with a straight edge--plus you can't lap convexity flat--gotta make it slightly concave, then lap. Cast iron plates work well, and as Bill says, a little diamond goes a long way. MSC has 6" rounds (1" thick) for $15 each. JWW's 'kanaban plates', 2-3/8" x 9" unknown metal, $14 each. Stanley plane upside down is another option. Also testing diamond paste on a black arkansas--seems like it should work, but 1/4 micron is too fine to do much. Gonna test 3 micron next.

Raising a burr. Diamond punches bigger than its nominal grit size, when it's on hard media. 15 micron on cast iron will peel back steel fast, and raise a burr right now. In comparison charts, 15 micron equates sizewise with an 800-1000grit water stone, but there is no comparison in cutting power. Partly this is particle size distribution in the diamond exceeding the nominal rating.

Carry Over. Carry over happens. I go from 15 microns to 3 microns to 1/2 micron. The 15 micron I wipe off on a dedicated cloth--quick, no fussing. From 3 microns down, I wipe off on a diamond charged leather strop (which is also useful), and wipe the final residue with another cloth--fast. Carryover is not preventing sharpness from happening

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Finish honing. When I get down to 1/2 micron, my old bald Norton diamond plate gives a better final edge than the cast iron plate (finished to 240grit). My theory is that a very fine edge requires a smooth surface, and the Norton is smoother than the iron. Think I'll relap the cast iron plate to 600 grit and see what happens then.

Comparison to ceramic stones. My edge test is that the blade should slice readily into the edge of unsupported newsprint with no sawing. 8K to 12K shapton will do this every time; it takes 1/4 to 1/2 micron diamond on a smooth plate to equal the shapton, and at that it helps to give the blade a final wipe on a strop. Theory: diamond gives a toothier edge than the shapton, and you have to go to ultra fine grits to approximate the cleanness of edge off the stone. .

I'm looking forward to more of Steve Elliott's 200X photos to see if these early observations agree or disagree with his, and why. I want to thank Bill for his methodical ways--I find it inspiring.

Wiley

Some Progress on Pics *LINK*

Steve Elliott

>I have a lot of microscope pictures of edges both freshly sharpened and after use, but haven't had time to do a systematic test and prepare it for posting.

As to the edges produced by different sharpening media (waterstones, diamonds, etc.) I've found the best edge to come from a Norton 8000x stone. My Takenoko finishing stone is also good, and so is the 1 micron diamond on cast iron. In actual planing, these edges perform equally well as far as I can tell.

I'm going directly from the grinder to 1 micron diamond, so I can't comment on carry over. I have found that there are always rogue scratches in the edge, which I now believe are due to coarser grit in the diamond paste itself. When I tried 1/2 micron diamond the rogue scratches were even worse, which tells me they're not due to grit left over from lapping the cast iron.

I'm going to post a link to my "not ready for prime time" site describing my testing. As I've been doing the work I've also been looking for a good way to present it online. I'd appreciate knowing what parts of the site are clearly presented and useful, and what parts are confusing. And if the site doesn't work on some browsers, I'd REALLY like to know what the problems are.

For microscope images of blades, follow the Steel and Sharpness link to Sharpening Media. There are some assorted images of blades after use on the single page linked to Results by Blade.


Not Ready for Prime Time Site

Re: Some Progress on Pics

Jim in Burlington Ontario

>Great work I can hardly wait to see the results. Thanks Jim

Re: Some Progress on Pics

Ernie Miller *Topeka

>Nice work but what is the bottom line? best blade with the best way to sharpen it. or do some blade sharpen better with differant mediums? I like reading this stuff but I am happy with the way I get my blades with this olf translucent stone I use. sure somthing might be better out there but is there a point where good enough is good enough.

Re: Some Progress on Pics

Wiley Horne--Glendora CA

>Ernie,

The reason I started with diamond is that I have a couple of favorite planes with M2 blades. IMO diamond or a motorized system is the best way to live with high-speed steel blades, even if you hollow grind them.

O1, A2, Japanese blades, vintage straight carbon steel--none of these need diamond IMO. I receive O1 blades from Larry Williams hollow ground and sharpened with translucent Arkansas and they are perfectly sharp. To me, that seems like the least costly way to have excellent sharpness with non-HSS steel. I do think you can make the argument that loose diamond is lower cost than a full Shapton setup.

Bill spoke of hollow grinding, and I agree with him that this is a good way to go for all blades thick enough to benefit from it.

Bottom line: I got into diamond to deal with M2, and I think Bill Tindall did it initially to deal with CPM 3V and then found it to be a cost effective system for overall use (hope I'm not misrepresenting Bill).

Wiley

Re: Some Progress on Pics

Ernie Miller *Topeka

>I guess that is why I am happy no fancy steel blades for be unless Steve uses them.

The Bottom Line

Steve Elliott

>You're right that good enough is good enough, and for me the edges I get with the fine waterstones and the diamond paste are all plenty good enough.

There is a significant difference in how quickly blades will reach a fine edge using different sharpening media. For the high alloy steels like M2 and CPM 3V diamond lapping is much faster. I sometimes add a little honing on the Norton 8000 after 1 micron diamond on these steels, and it's still faster than using only the Norton. For regular carbon steel and A2, the waterstones cut fast enough.

I started this project because I wanted to determine if the high alloy steels give performance that is enough better to be worth the trouble. I haven't answered that question yet, but I have developed my skill at sharpening and using smoothing planes. This is my hobby, and right now the bottom line for me is just enjoying the process.

Motivation

bill tindall

>I don't plane to achieve a particular looking planed surface. I plane and shave and chisel to remove wood faster and less messy than alternatives for shaping and fitting. My sharpening objectives are getting a useable edge quick and cheap. So I have nothing to offer on whether diamond produced edges result in better finish or even longer life (though I would love to see quantitative data on the latter if someone ever figures out how to get it).

For someone that already has invested in an effective sharpening routine that works fast enough, I see no reason to switch to diamonds and I would not recommend someone to do so.

But for someone starting out, a bench grinder, and loose diamonds on acrylic(if acrylic proves useful long term) would be the cheapest, fastest way to get a very good edge on tools, The diamond part of the investment would be as little as $50 and the best grinding wheel another $30. Some people would find this entry price an attractive alternatitive to the various "stone" options who's price is daunting, or even the popular abrasive sheet option with its flatness issues. For this reason the diamond approach seems worthy of further investigation, and consideration by anyone starting out or unsatisfied with speed or quality of their current approach.

As an aside I now use this same approach for lathe tool sharpening. I hollow grind gouges and quickly refine the edge with some diamond powder on a small piece of cast iron or acrylic. I will resharpen with the diamond many times before I revisit the grinder. The very fast cutting of the diamond enables this approach to be fast enough.

I received some data on grindability of tool steels today. O1 and A2 are considered soft (in the context of tool steel abrasion), M2 is considered medium and the vanadium steels like M4 and 3V are rated hard.

M2 and microchipping

bill tindall

>I made a chisel from M2 and it dulls by microchipping very rapidly, bevel 26 degrees (I was warned it would by knife makers). Is this not a problem with the plane iron? What bevel angle? I don't know the origin of this M2 so I may not have a typical material.

Re: Motivation

Wendell @ Murphy, TX

>Holy Cow!!! A2 is considered soft! Wow. Remind me not to buy an M2, M4, or V3 blade. I takes me alot longer to sharpen an A2 blade than an O1 blade. I was considering a getting a diamond setup just for the initial sharpening of a new tool. The initial sharpening seems to take me forever and I would dearly love to speed this up. What would you recommend for this purpose?

Wendell

nothing beats power for material removal

bill tindall

>To estabilsh the initial shape of bevels on lathe tools, chisels, plane irons etc something powered will be faster , especially on the hard to grind materials. Everyone needs a bench grinder for lawn mower blades and the like (although I use a big file) so a cool running wheel on a bench grinder is an attractive option. A cool running wheel will be pink or white, 60-80 grit, H or softer and ideally open structure( but medium is OK).

For initial back flattening, a powered flat wheel is faster than any hand operation, but one only does this once so it may not make sense to buy a powered arrangement for this task.

Hard to grind means slow abrasive wear which is very useful on lathe tools and may be useful on plane irons. I don't see that it has much relevance on chisles.

Re: M2 for plane irons

Wiley Horne--Glendora CA

>Bill,

I don't know the dulling mode of my M2 irons, but would trust the experience of blade-testers Brent Beach and Steve Elliott with M2. Each of them has an Academy Saw Works blade, which I have read are M2. Mine are Ray Iles brand.

You asked whether M2 is a suitable plane blade. The plane maker, Konrad Sauer, offered M2, A2, or O1. I chose M2 because that's what he liked, and also because of the performance of the Academy Saw Works M2 blade in testing in Australia, where it won a strenuous competition involving Aussie timbers (Holtey A2 was the runner up--all reported in OLDTOOLS Archives). Later, Roger Nixon did some testing that was won by the Academy blade, and I notice than on Brent Beach's site, the Academy blade showed less wear after a given number of planing passes than the other blades tested.

Brent and Steve are still doing tests and there's more data to come, but M2 has done well so far in head to head competition as a plane blade. Its durability in the Australian tests leads me to think it is not given to rapid edge failure, because that was mean wood they were planing, and the test was a durability test (not surface finish). M2 will also drive you to diamond sharpening.

For No. American hardwoods, it seems to be a coin toss and personal preference between the various steels--you pay the price in sharpening for alloy steel. For Aussie timbers, I suspect high alloy steel is pretty much a necessity. Does anyone know which of the high-speed steels HNT Gordon uses?

Wiley

Very interesting

bill tindall

>If M2 makes a more durable iron than A2 that is very interesting and it suggests that harder and/ or more wear resistance is better and that toughness is not so important. Extrapolating properties it further suggests that M4 might just be awesome.

Form time to time someone on the other side proposes hand sharpening M2 jointer or planer kinives. I never saw a report on their success(snicker). M2 doesn't even grind very fast with a power grinder!

I use M2 blade in main plane

Andrew F in Australia

>And have probably gone about 3 months since I last sharpened - no, not because I'm lazy, just that it's not blunt yet.

Cheers,

Andrew

flatness

Jonathan Ronnow, Sweden

>"or even the popular abrasive sheet option with its flatness issues"

well... those are gone since I bought the 3M microfinishing and lapping films. Stick them on glass and you will get flat... There will be some unflatness present when the abrasive wears, but I have no real idea of how much that matters.

Im not arguing with you, just sharing my experience.

I had trouble with sic and ao paperbacked, but the 3m�s on mylar works really good. And the psa helps, too. I still accidentally cut into the films if im freehanding without a hollow to guide me, or when Im touching a large wire edge onto the finer 5 & 0.5 films. But thats lack of pratice i suspect...

Jonathan