High Carbon or A2 - Which do you use / prefer

[protectedvoid]

Going to be purchasing a Hock Plane Blade and Cap Iron and I'm wondering which ones most of you prefer. I know the basic differences between the High Carbon and A2 metals, but what I'd really like to know is your experiences working with each. Specifically, how often you actually sharpen them, how they perform on extremely tough or figured wood, etc.

I'll be looking to add these to my #4 smoother and my #6 Fore.

Thanks.

[Jonathryn]

In my experience A2 crumbles a bit at first, then makes an excellent iron that keeps a keen edge for a long time. Once it's dull though it's dull. I think you can get O-1 tool a tad bit sharper than A2, but you have to sharpen more frequently. The transition from sharp to dull is a bit more gradual, it seems to me; it degrades more gracefully. If you know how to sharpen, almost any tool steel is good. I think the best rationale for getting new irons is to get irons that are as thick as your plane can handle; more mass reduces chatter and disperses heat buildup. If the blade is too thick though the depth adjuster can't reach the chip breaker.

My advice: A2 for the #6 and either O-1 or A2 for the smoother. You do a lot of heavy hogging with the #6 and don't want to be sharpening that all the time. Since you're doing finish surface with the smoother, you'll want to be sharpening the iron frequently anyway and just my preference but I like O-1 for that better. I keep a strop near the bench to touch up the edge of all my tools.

[jlloydparks]

First question is what is your sharpening system? Some are better with A2 than others. I use oil stones and they handle both types well, however, it takes less time to sharpen an O-1 blade. I can even sharpen that D2 stuff that Ray Iles uses in his mortise chisels, however, it takes a whole lot longer.

I do notice that O-1 gets sharper, but A-2 stays sharper longer. I agree with Jonathryn I might get the A-2 for the #6 and definitely an O-1 for the #4. Will make them easier to compare later.

Just as a reference I have been replacing my Lie-Nielsen stuff that came with A-2 with their new O-1 replacements including chisels. I love O-1 and much prefer it on oil stones. So honestly I would only be putting O-1 on my planes from now on.

[protectedvoid]

First question is what is your sharpening system? Some are better with A2 than others. I use oil stones and they handle both types well, however, it takes less time to sharpen an O-1 blade. I can even sharpen that D2 stuff that Ray Iles uses in his mortise chisels, however, it takes a whole lot longer.

I do notice that O-1 gets sharper, but A-2 stays sharper longer. I agree with Jonathryn I might get the A-2 for the #6 and definitely an O-1 for the #4. Will make them easier to compare later.

Just as a reference I have been replacing my Lie-Nielsen stuff that came with A-2 with their new O-1 replacements including chisels. I love O-1 and much prefer it on oil stones. So honestly I would only be putting O-1 on my planes from now on.

Well, to answer the first question, I use a honing guide with wet / dry sandpaper and a granite substrate -- the scary sharp method, I believe. To establish (or re-establish) the primary bevel to the proper angle, I use a 320 grit / 750 grit diamond stone. Once I have the primary bevel established, I begin sharpening and polishing the edge by working through the various grits: 1000 grit > 1500 grit > 2500 grit > 9000 grit. I also lap the back of the irons flat as I progress from one grit to the next to ensure that I have removed any burs that may have formed. The end result is an iron that is polished to a mirror finish that easily shaves the hair from my arms.

I've been working with some curly maple and jotoba recently. The jotoba is very hard stuff, and the curly maple is definitely a little more difficult to plane than regular rock maple. I don't mind if I have to resharpen and hone the iron a little more frequently if I gain the benefit of a truly sharper edge.

I guess the real question is, how often *should* I have to sharpen them? I realize that in time, I'll know when the blade has gotten too dull, but I'd hate to not pick up on it soon enough, and have tear out. I also know that working with extremely hard and figured woods will require sharpening more often...but it's the "how often" part that has me puzzled.

[jlloydparks]

I guess the real question is, how often *should* I have to sharpen them? I realize that in time, I'll know when the blade has gotten too dull, but I'd hate to not pick up on it soon enough, and have tear out. I also know that working with extremely hard and figured woods will require sharpening more often...but it's the "how often" part that has me puzzled.

That is one of those million dollar questions. I have taken to the practice of honing every blade I use at the end of my woodworking session. I do it free hand and it goes quickly. That way everything is ready to go next time I come into the shop. However, how to tell when to stop and hone or resharpening in the middle of the project before you get to the ugly tear out point that is an art that I have yet to fully master. It depends on the wood first of all. I could probably plane poplar or white pine for a month without ever having to touch the iron to the stone. But curly maple and jatoba is the other end. I always look for those first signs of small tear out or lines as indicators to sharpen a blade.

I did a small table of curly maple with a 19"x19" top. I made it through finishing the top with a smoother without having to sharpen, but I made sure the iron was the best it could be before it hit the wood. I only took two very light (~0.001) passes and called it done.

[protectedvoid]

That is one of those million dollar questions. I have taken to the practice of honing every blade I use at the end of my woodworking session. I do it free hand and it goes quickly. That way everything is ready to go next time I come into the shop. However, how to tell when to stop and hone or resharpening in the middle of the project before you get to the ugly tear out point that is an art that I have yet to fully master. It depends on the wood first of all. I could probably plane poplar or white pine for a month without ever having to touch the iron to the stone. But curly maple and jatoba is the other end. I always look for those first signs of small tear out or lines as indicators to sharpen a blade.

I did a small table of curly maple with a 19"x19" top. I made it through finishing the top with a smoother without having to sharpen, but I made sure the iron was the best it could be before it hit the wood. I only took two very light (~0.001) passes and called it done.

Yeah, I figure both the curly maple and the jotoba will let you know rather quickly that you're working with a dull iron. Though it looks like I'll likely go with the O1, I think I'll hold off just a bit until I can get more feedback, though what's already been given has been most helpful.

[lwllms]

Yeah, I figure both the curly maple and the jotoba will let you know rather quickly that you're working with a dull iron. Though it looks like I'll likely go with the O1, I think I'll hold off just a bit until I can get more feedback, though what's already been given has been most helpful.

I could write about the metallurgy involved and what you should consider but I like an analogy better. The newer more exotic steels are like modern varieties of tomatoes. The tomato you buy at the store was part of a high yield harvest, it's perfectly shaped, you can dribble it down the grocery store isle and not bruise it, and it'll keep on the shelf for weeks. It'll even look great in a salad but it'll taste like cardboard. These more alloyed steels are similar, they have all kinds of advantages for the supply chain but come up short for the end user.

Writing about the metallurgy is long and boring. My experience with doing that tells me no one reads it and it's a waste of my time.

[Jonathryn]

Yeah, I figure both the curly maple and the jotoba will let you know rather quickly that you're working with a dull iron.

Those woods might benefit from using W-1 or 1095 steel -- in the form of a scraper!

[protectedvoid]

I could write about the metallurgy involved and what you should consider but I like an analogy better. The newer more exotic steels are like modern varieties of tomatoes. The tomato you buy at the store was part of a high yield harvest, it's perfectly shaped, you can dribble it down the grocery store isle and not bruise it, and it'll keep on the shelf for weeks. It'll even look great in a salad but it'll taste like cardboard. These more alloyed steels are similar, they have all kinds of advantages for the supply chain but come up short for the end user.

Writing about the metallurgy is long and boring. My experience with doing that tells me no one reads it and it's a waste of my time.

That's a pretty good analogy. -- BTW, I don't find metallurgy boring. My uncle is a chief metallurgist for Corning, Inc.

[protectedvoid]

Those woods might benefit from using W-1 or 1095 steel -- in the form of a scraper!

They'd take a long time to flatten using a scraper.

[jlloydparks]

Larry,

The tomato analogy was the best. Way to put it in terms we all can digest!

Josh

[bois]

In my experience, A2 steel can be quite challenging to sharpen using many of the common methods used in most shops. I find that sand paper and even water stones can really take an excessively long time to hone with. However, I have spoken to a few people that have had great luck with the Shapton glass stones getting A2 steel sharp much more quickly. In theory, A2 should hold an edge longer, but the problem is when the edge does break down it literally crumbles at the edge. The problem is when this happens, you have to grind a new bevel which requires removing quite a bit of steel. So I find that I hone my A2 irons just as often as my high carbon just to avoid that complete failure of the edge. I also tend to agree with the theory that A2 doesn't get as sharp. I'm not sure if it's just harder to get that razor sharp edge, or if it really just can't get as sharp as O irons.

[PurpLev]

in my recent purchase from LV, I went with O1 (my first "new" plane that I could choose the blade for). the way I look at it - you'll be sharpening frequently anyway, so I'd rather have the extra sharpness, and the gradual dulling then not. I mean, it's not like with an A1 you won't be sharpening it at all - just less frequent. as long as you don't wait too long, sharpening shouldn't be that big of an issue.

that's my take on it - and I'm sticking to it!

[protectedvoid]

in my recent purchase from LV, I went with O1 (my first "new" plane that I could choose the blade for). the way I look at it - you'll be sharpening frequently anyway, so I'd rather have the extra sharpness, and the gradual dulling then not. I mean, it's not like with an A1 you won't be sharpening it at all - just less frequent. as long as you don't wait too long, sharpening shouldn't be that big of an issue.

that's my take on it - and I'm sticking to it!

No, sharpening doesn't take that long at all. Even using the sandpaper method on granite substrate, it only takes me about 3 minutes to re-sharpen an iron. So, let's assume that I'll go with the O1 irons. Which, then, would most of you prefer? Ones from LV or ones from Hock?

[protectedvoid]

In my experience, A2 steel can be quite challenging to sharpen using many of the common methods used in most shops. I find that sand paper and even water stones can really take an excessively long time to hone with. However, I have spoken to a few people that have had great luck with the Shapton glass stones getting A2 steel sharp much more quickly. In theory, A2 should hold an edge longer, but the problem is when the edge does break down it literally crumbles at the edge. The problem is when this happens, you have to grind a new bevel which requires removing quite a bit of steel. So I find that I hone my A2 irons just as often as my high carbon just to avoid that complete failure of the edge. I also tend to agree with the theory that A2 doesn't get as sharp. I'm not sure if it's just harder to get that razor sharp edge, or if it really just can't get as sharp as O irons.

Thanks. I hadn't really thought about that. It would definitely suck to have the iron's edge crumble on you midway through a shave. So, I suppose the O1 would be the better way to go.

[lwllms]

in my recent purchase from LV, I went with O1 (my first "new" plane that I could choose the blade for). the way I look at it - you'll be sharpening frequently anyway, so I'd rather have the extra sharpness, and the gradual dulling then not. I mean, it's not like with an A1 you won't be sharpening it at all - just less frequent. as long as you don't wait too long, sharpening shouldn't be that big of an issue.

that's my take on it - and I'm sticking to it!

If one understands the steels, your experience makes sense. A-2 steel's increased abrasion resistance comes from forming carbide inclusion in the steel during heat treating. Forming those carbides requires high heat treating temperatures and a long soak at high temperature. One rule of heat treating is that achieving fine grain requires careful preheating and raising the temperature of the steel only to critical temperature and keeping it there only long enough to get a uniform temperature throughout the steel. The heat treating temperatures and long soaking time of A-2 results in a coarse grained steel that surrounds the formed carbides. Fine Woodworking did a test of chisels several years ago where they actually did fracture tests and checked the grain size of the steel. As one would expect those with the finest grain had the best edge quality and viability.

The carbides in A-2 aren't structurally part of the steel. Imagine a sheet of ice with pebbles spread through it. If one were to make a big cutting edge, some of those pebbles would end up on the edge. The problem is nothing is holding those pebbles in place. They're prone to just falling out which is exactly what PurpLev is describing. This is why some manufacturers suggest more obtuse bevel angles with A-2, they're trying to encapsulate those carbides to keep them held in place by the relatively coarse grained steel. D-2 steel is similar but the carbides are much bigger and the edge failure more dramatic.

So what about the resistance to abrasion? Well, A-2 does have higher abrasion resistance. However the abrasion resistance the industry is talking about is abrasive wear to a flat surface. If one was sanding a pine board with thousands of tiny knots, those knots would add abrasive resistance to the surface and slow down your sanding. This has very little to do with edge wear. In fact, edge wear on things like plane irons is usually caused by adhesive wear. The cutting edge isn't being worn away by cutting action of some abrasive, it's being worn by molecules being transferred through adhesive wear. A-2 and O-2 steel have virtually identical resistance to adhesive wear. If you scroll to the bottom of this link, you'll see this verified:

http://www.bucorp.com/files/aisi_o1.pdf

The only abrasive resistance the woodworker will likely experience with A-2 is increased difficulty in grinding and honing. Wow, that's something I'm looking for, more difficult to sharpen.

So what advantages are there in A-2? When heat treating tools like O-1 each tool needs to be individually handled by the person doing the heat treating and A-2 can be done in large batches. This saves both labor costs and energy costs for the manufacturer. Also, if you look at the chart at the bottom of the link above you'll see that O-1 will distort more than A-2 as a result of heat treating. This means the manufacturer has less labor and costs in the final preparation of the A-2 tool.

There's more I could write but I don't think anyone is going to read this and I've already invested more time than I intended.

[wilburpan]

There's more I could write but I don't think anyone is going to read this and I've already invested more time than I intended.

I did, and I will.

[protectedvoid]

There's more I could write but I don't think anyone is going to read this and I've already invested more time than I intended.

I read it, and found it quite informative, actually. In point of fact, I think this explanation pretty much sealed the deal on sticking with O1 for me.

[Jonathryn]

I read it, and found it quite informative, actually. In point of fact, I think this explanation pretty much sealed the deal on sticking with O1 for me.

I don't think A2 is all that bad. When it gets "dull" you get streaks in the surface you're planing because the edge is chipping. If you're using a #6 to dimension wood, that's fine, and A2 is great because streaks in the wood doesn't matter. You don't have to stop everything and sharpen--it can wait till you're done with this job. If it's a show surface, just go over it with your smoother with a sharp O-1 blade and get the streaks out. When O-1 starts getting dull, the surface doesn't look or feel right, rather than chipping and leaving streaks all over the place: Time to sharpen. And if you're dealing with gnarly grain you can touch up spots here and thee with a card scraper. Nobody uses a W-1 scraper to dimension wood like a jointer or fore plane, btw. I wasn't suggesting that above.

[PaulMarcel]

There's more I could write but I don't think anyone is going to read this and I've already invested more time than I intended.

Excellent post! I'd definitely read the rest.

[protectedvoid]

I don't think A2 is all that bad. When it gets "dull" you get streaks in the surface you're planing because the edge is chipping. If you're using a #6 to dimension wood, that's fine, and A2 is great because streaks in the wood doesn't matter. You don't have to stop everything and sharpen--it can wait till you're done with this job. If it's a show surface, just go over it with your smoother with a sharp O-1 blade and get the streaks out. When O-1 starts getting dull, the surface doesn't look or feel right, rather than chipping and leaving streaks all over the place: Time to sharpen. And if you're dealing with gnarly grain you can touch up spots here and thee with a card scraper. Nobody uses a W-1 scraper to dimension wood like a jointer or fore plane, btw. I wasn't suggesting that above.

I know. I was just "funning" with you. I actually have my #6 set up to act as more of a jointer, taking very fine shavings to flatten a surface. I've set my #5 up to be more of the aggressive dimensioner. Once I get a hold of a #7, I'll reconfigure the #6 for heavier stock removal, but I really, really enjoy my #5, and I'm getting better at reading it as I plane. I think given the difference between the two, I'll likely just stick with the O-1 irons. As often as I'll be using the hand planes, I might as well keep the sharpening process as easy as possible.