O1 & A2 dilemma

Alloys and Bevel Angles *LINK*

Steve Elliott


>Carbon steels like 01 do have better resistance to chipping than A2, so your idea of using the O1 blade with a bevel of about 30 degrees and the A2 blade with a larger bevel angle is a good one.

There's another reason I'd suggest using the A2 blade for the higher angle cuts, and that is blade wear. Higher angles cause the blade to become dull more quickly and the better edge retention of the A2 will be an advantage.

There are some preliminary results from my tests at the link below.


Blade Bevel Angle Tests

Re: Alloys and Bevel Angles

Miles


>Steve, thanks! When I was writing my question I had a mental block and couldn't remember whose pages had the angle data - sorry about that. As a technical type I find the systematic testing very confidence-inspiring, & a very valuable reference point for this sort of thing. Your pages (and Brent's) should be permalinked from WC! I read all of them some time back with great interest.

The A2 blade is significantly thicker than the O1 - good thing I have some diamond hones available to grind it with!

cheers

Miles

Re: Alloys and Bevel Angles

Chris Scholz


>Wow, those are amazing measurements As a scientist this really answers a few questions (i.e. what is the utilmate best blade/sharpening medium)

As an engineer I am thinking along these lines:

* most (many?) folks seem to prefer water/oil stones over diamond (maybe a legacy thing, maybe habit, maybe they are just happy with it, maybe something else, or maybe I am wrong and most woodworkers use diamond paste these days)

* using water (how bout oil ?) stones high carbon steel blades take a sharper edge but dull faster as compared to alloy/PM steel

Now let's look at "use cases":

* for a smoothing plane I want to have an edge that is as sharp as possible and lasts "reasonably long" and is "easy" to sharpen (ideally without jigs so I can hit the stone and go back to business in a hurry)

* for a jack plane I want to have an edge that last as long as possible and is "reasonably" sharp and I probably can afford to spend more time/efford putting the blade to the stone.

Putting this all together, does that mean the following?

1) for a smoother I want to use a traditional high carbon steel blade (ideally laminated to make the blade easy to sharpen)

2) for a jack plane I want to use an alloy steel plane

Maybe the attached conceptual graph makes my reasoning clearer.

What do y'all think?

Chris, Atlanta, GA

Magnificent work, Steve!!

Wiley Horne


>And extraordinarily ambitious. Miles is right--your site should be a permanent link for W/C. You characterize your findings as 'preliminary', but those of us who have been following this over time know that much work and rework has gone into the methods and control studies--so the foundation is solid.

I hope the readers will take some time to look through the menu of work you have undertaken. For example, under 'initial sharpness' it becomes clear that all the steels will become about equally sharp, provided the right abrasive is used. Another remarkable finding under I believe, 'bevel angles', is that lower included angles will start sharper and stay sharper, provided the steel will take the load. There are gems like this in a number of the menus.

Wiley

Re: Alloys and Bevel Angles

Steve Elliott


>Chris,

Your idea for using a carbon steel blade for smoothing and an alloy blade for prep work is a good one. My own choice of blades has been driven by the need for blades that don't have to be honed often. I've worked in over a dozen cabinet shops since 1979 and none of the owners wanted to see me honing a blade. They'd suggest some kind of sander if they saw me honing, and sometimes a plane is just the best tool for the job. I now have blades that will last plenty long enough that I can wait and sharpen at home.

I'd like to see diamond honing become easier to do. The biggest obstacle is scarcity of appropriate cast iron lapping plates. I've heard Lee Valley may offer them, and hope that comes through. I've found cast iron to be notably better than hard maple or acrylic (Plexiglas) for fine honing. Acrylic works much better with coarser grits than with fine ones. With good grinding technique it's possible to go directly from the grinder to a fine diamond paste for a pretty quick, killer sharp edge.

Yes, Steve has made a real contribution!

Lyn J. Mangiameli

Re: Magnificent work, Steve!!

Miles


>I know that there have been occasional reactions _against_ getting too techno-scientific about things, as it can seem exclusive against the folks who don't have that background, for whom 'trustworthy craft'/practicality is more convincing than a reduction of the question to a set of more abstract elements for analysis. I'm on the techie side, so I love what Steve, Lyn, and Brent have been doing (just think of the patience!) and I keep finding similar rigorous testing of other things in the academic wood literature, some of which could be really helpful in answering some of the 'arts & mysteries' type questions that come up. It seems that everyone here is sensitive to the subtle variations of performance and efficacy that they find when working, but it's a long road to separating out all the different contributions and determining what is actually going on. Is it the steel, the wood, moisture content, applied force, bevel angle(s), speed of cut, skew, grain, or something else that is making your plane blade cut well or badly, & blunt fast or not...?

If I get time, I will extract some typical examples from classic work on wood strength, machining and so on, that look interesting to me. I'm lucky to have one of the world's great libraries here, and there are a few gems on this sort of thing. I have one with loads of systematic work done even before WW2 that I am browsing through at the moment. If anyone is particularly curious, say so & that will encourage me to go digging!

Of course, I still _do_ appreciate the craft side and marvel at what people do by just getting on with it... perfect tools or not! I don't want to achieve 'paralysis by analysis'...

cheers

Miles

Re: Magnificent work, Steve!!

Wiley Horne


>Miles,

Yes, please post findings you find interesting from the literature at your disposal. Data is always interesting. It seems there will always be 'arts and mysteries' because there appear to be few limits to what skill + practice can achieve. But data does help clarify and sort out differences in context when anecdotal reports contradict each other.

2 cents.

Wiley

enthusiastic yes

bill tindall

Re: Alloys and Bevel Angles

Chris Scholz


>A boss watching you (and objecting to) honing blades. As a hobbyist thought never crossed my mind! I'll be watching your site for more of your outstanding analysis.

Re: enthusiastic yes

Miles


>Well, with Bill 'Diamond Geezer' Tindall, Chris 'FEA' Scholtz, and Steve 'patience' Elliot all encouraging me, I will have to do what I said!

For those interested, the book I'm looking at for now is "Principles of Wood Science and Technology Vol. 1, Solid Wood" compiled by Franz F.P. Kollmann & Wilfrid A. Cote Jr., Published in 1968 (a good year... I was born September!) Library of Congress Catalog 67-29614.

This book is a mine of fascinating information and a testament to the people who measured, tested, and analysed thousands of wood samples to generate the graphs of various properties. I've attached one example, showing how moisture content through the thickess of a 2" plank changes with drying time (starting with green 'hardwood'). Sorry it's low-res, the 40kb limit cut in! I know this data is situation-specific, and would vary with length and drying conditions, but still shows what sort of detailed testing has been done and that is there for anyone who is interested.

I can scan the table of contents (very detailed) & send to anyone who wants to know in more detail about some specific area.

cheers

Miles