Full Chisel Blog

August 16, 2010

Why laminated [laid] blades are better.

Let me make one thing perfectly clear, I am not commenting on the quality of the steel used then and now. I am not saying that the old steel was better than the new steel, I have no idea and for this discussion, I really don’t care. That is not the point. For the quality of steel is only one small, I repeat small portion of the overall equation.

By laminated blades, be it chisels or plane irons; I mean tools made largely of wrought iron with a thin veneer of steel forge welded to the cutting edge. Now I would like to take to task those who say that this was done because of economy; steel is more expensive than wrought iron. In the nineteenth century steel costs 5 times that of iron and the steel on these old tools is usually less than 10% of the blade. Then there is the two or three heats it takes to forge weld the steel to the wrought iron. There is no economy, it would have been cheaper to make them of solid steel, but they didn’t and here is why.

First steel will hold an edge longer than the softer wrought iron and the iron could not be hardened like steel. The steel had to be reduced by forging to the thin veneer before it is forge welded to the wrought iron. This forging, both in making the thin slips of steel but the forge welding to the iron as well, compacts the grain of the steel. It even happens today following the same process, and the tight grain in the steel produces a higher quality steel.

However the most important result of this process is that the completed forge welded laminated [laid] steel blade can be hardened by quenching in brine, producing a very hard and brittle steel. If it were made of solid steel then it would need to be tempered in order to remove some of the hardness or the tool would break as the solid steel with be too brittle. Made largely of wrought iron, which can’t be hardened, the steel can be hardened much harder than a solid tool. And because it is supported and protected by the soft iron, the steel can be left very hard from the brine quench.

Some say the older tools have better steel, I am not sure the steel was any better but the process did leave the thin veneer of steel very hard, holding an edge longer. And when grinding and sharpening only a small amount of the hard steel is ground/sharpened while the bulk of the tool made of wrought iron is easy to remove.

So let me say it once again, it is the combination of iron and steel that makes for a better blade, probably reduces chatter [as opposed to a solid steel blade], puts the center of gravity toward the cutting edge of tapered plane irons and can be made much harder because of its unique structure.

Stephen

9 Comments »

  1. I have to disagree. I fully agree that a drawn out and forged steel tool produces a better edge than rolled steel that simply hardened and ground.

    However I think your labor calculation is off.

    Plane blades are tapered. The tapering was forged in. It’s a lot lot easier and cheaper to make an easy to forge mild steel (wrought iron) sort of tapered iron, weld on a steel cutting edge, finish the taper and be done with it. Than it is to forge out and entire tapered steel iron. This changes for parallel irons which are far less expensive to make in any material – as long as you don’t need to weld on a cutting edge.

    Whatever labor in a tapered iron is saved by not having to do a weld is lost by having to forge a taper into the harder steel tool.

    Brierly (sp?) writing in the late 19th century said (and he was one of the first steel chemists) that steel of the 19th century wasn’t better in the sense that they knew specfic formulations but it was better for chisel making because they understood that cast steel comes in different properties and sold the appropriate steel from the appropriate forge for different uses. one of my mid-19th century catalogs lists over a dozen different types of cast steel – all designed for different listed uses.

    Comment by joel — August 16, 2010 @ 9:15 am

  2. I can’t comment on modern steels versus old forged steel, other than that my experience is that my better plane blades (O1 steel) hold an edge just as well as my older, laminated blades, such as my wonderful W. Butcher chisels.

    However, what I will say, as a user, is that I really appreciate how much easier it is to shape and sharpen laminated blades. It works to an another advantage in that I tend to keep those blades in better shape because it doesn’t take so much effort to sharpen them. On the other hand, when I’m looking at sharpening the thicker, modern blades, I know what I’m up against. In fact, one of the reasons I use my Millers Falls #9 (basically a Stanley #4) a lot is because the blade is thin and I know it’s going to be easy to sharpen. I replaced the cap iron with a Hock, but intentionally left the original blade. (I guess I really ought to rehab that old coffin smoother, huh?)

    I got a couple of laminated-blade tools in Taiwan early this year, and they’re great. I don’t know if the cutting steel is forged or what, but they hold an edge properly and they’re easy to sharpen. And of course, there are always the Japanese tools.

    Comment by Brian — August 16, 2010 @ 9:41 am

  3. Stephen,
    Checkout this Japanese Video of a smith forging a tapered laminated plane blade at http://web.mac.com/nami_aru/Daiku/Kanna.html

    Joe

    Comment by Joe — August 16, 2010 @ 11:11 am

  4. I also think there’s a flaw in the reasoning.

    The toughness of steal does not only hold for the whole tool, but for the cutting edge. Properly sharpened, the cutting edge should be so fine as to be almost non-existent. Out there, where the shaving is actually being cut, the wrought iron backing isn’t doing much to shore up the hardened edge.

    Any hardened but not tempered cutting edge would be too brittle to stand up to the punishment of using the tool. In effect, the hardened and not tempered edge would crack and chip under use.

    I’ll be those laid steel tools are not only hardened but also tempered.

    Comment by Jerome Weijers — August 16, 2010 @ 1:25 pm

  5. Here is one to ponder? Why go to all the work of making a tool and not using steel? I acquired a pair of 18th century tinsnips. (they have exaggerated tips as shown in the Diderots Encyclopedia). They were made completely of iron and I can only cut once before I need to resharpen them.

    Shay Lelegren
    Tinsmith
    Hot Dip Tin

    Comment by Shay — August 16, 2010 @ 7:24 pm

  6. Stephen, sorry, you are not compacting the steel (or the wrought iron) by forging it. You can change the grain size by cold working than takining it above the critical temperature for a short time before cooling it either by quenching or just air cooling it. You can also affect grain size by just cycling above the critical temperature and then air cooling to achieve a finer grain size – modern knife smiths often do this with 52100 steel used for knife blades they usually use a max of 3 times above the critical and cooling before heating above it to quench and then temper.

    I suspect that an as quenched wrought iron/steel combination would have an extremely brittle edge that would tend to chip, so I suspect that they tempered them. USe of brine for a quenchant just indicates that they had to use a severe quench to get the steel portion hard (indicative of very few alloying elements) – severity of quenches (in reverse order (severe to mild)are: brine, water, oil, air.
    Kevin Haffey
    Quality Metallurgist
    North American Hoganas

    Comment by Kevin Haffey — August 17, 2010 @ 10:56 am

  7. The softer steel(iron) was used as the major portion of the blade because it was much easier to shape and finish. The iron and and the smithing
    skills to work it were in abundance. The laminated plane blades and chisels are a joy to sharpen because of the softer metal. Some drill bits were
    laminated also giving it the advantage of bending rather than being broken in the hole.

    Comment by David Taylor — February 28, 2013 @ 2:20 pm

  8. If I may; in a wooden smoother, the mass of iron concentrated near the cutting edge serves to dissipate heat (planing is hot work), and to balance the tool. In an iron plane, the weight is in the sole, and heat transfers readily from the blade. Brass wear plates will get too hot to touch with just a few minutes planing. Yes, the laminated irons were probably tempered; edge-holding varies considerably from one blade to another. In framing chisels, the iron mass absorbs shock better than solid steel (I prefer Barton to Barr), modern steels can be much harder at the cost of requiring more effort to sharpen and still (frustratingly) not hold an edge as well (e.g. Sorby, Marples). Most sharpening effort (in my experience) is expended on the back of the blade, not the bevel. Work on the bevel is mostly a matter of wasting material without overheating, lapping the back (steel in either case) flat is where the real work happens. Your new Hock blade is flat, the 150-year-old Butcher chisel probably isn’t.

    Comment by michael langford — July 20, 2013 @ 4:59 pm

  9. hello.i suppose that all has been said above,except,it really doesn’t take that much time to make the weld on a piece of laid steel.i own a small shop called kalapooia forge,and i make mostly knives,edge tools and black powder gun parts.ALL the edge tools ans most of the knives i make are laid steel.trust me,you need to temper laid irons,chisels and etc.you make a harder temper is all.the reason is when you forge weld the steel to to iron,some of the carbon migrates in to the iron.that is the reason one would use brine.if i was to not temper i would use oil,slower quench.does this make sense.thank you for bringing the issue back from the cobwebs of history and for giving some old tools a purpose and a sense of life again. kalapooia forge-*Mike Blair-maker*

    Comment by mike blair — May 7, 2014 @ 4:40 pm

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