Chisel Tool Steel (A-2, O-1, Chrome Vanadium) & Low-Angle Bevels

[Jim Neeley]

I've received Rob C's dovetail DVD's and have a selection of A-2 steel bench and dovetail-paring chisels, a dovetail saw and the rest of the necessary assorted equipment on order, intending to give a go at Neandering starting with hand cut dovetails.

On the L-N site (in the section where they offer their O-1 chisels) I've read that A-2 steel, while holding an edge for a long time, doesn't hold up well to a paring angle of less than 30*; that L-N recommends the O-1 for low angle bevels.

I have an old (15-20 year) unused 6-piece boxed set of Marples Blue Chip chisels as well as a well-beaten 1" Olympia. I'm contemplating the destiny of the blue chips. If I thought they'd hold up fairly well I'd 25* angle sharpen them and reserve them for soft wood hand paring. If they wouldn't or were generally POS's I'd sharpen them to 30* or 35* and use them as mortise chisels until they self-destruct or I can afford to replace them.

Does anyone know what kind of steel is in the older blue chips or how they hold up to low angle (i.e. 25*) sharpening? The new ones are advertised as "solid forged chrome vanadium". With my lack of knowledge in metallurgy this doesn't tell me much either.

I would sure appreciate insight from someone who has tried this (or has insight), successfully or not! <g>

[David Weaver]

set one up. If they are "sheffield steel", they should be similar to O-1 ... very similar.

Whether or not they hold up at that angle will depend on their hardening. If they have a little bit of chipout, grind them back a 16th and re-establish the edge.

If they happen to be fairly hard, they'll be as good as anything else, especially if they are old enough to have the disirable delicate edges.

A while ago, a buddy and I had some chisels tested. The softest one I had (an old witherby, but not that old - had the shiny metal that doesn't rust) wouldn't hold an edge at all below 30 degrees, and even at that, it wasn't great. To no surprise, it tested at 53. Everything that was in the high 50s and low 60s held an edge pretty well (low 60s was the only offered japanese chisel we had - a mortise chisel - I didn't want to let any of my japanese chisels get struck).

I tried to give away the witherby chisel and someone gave it back! I mailed it for free to someone along with something I sold. It'd probably work just fine if someone rehardened it, but I had no interest.

Anyway, you see a lot of pre-irwin blue chips in shops where people work for a living and don't want to spend more than they have to for chisels. Give them a try.

[Casey Gooding]

Older Blue Chips tend to be good chisels. I think quality has gone down since they started stamping Irwin on them. I have a set I used as my work chisels for years (I wasn't about to take my Lie-Nielsen's or Ashley Iles or Japanese Chisels to work. Yes, I have a chisel problem.)
They have always worked quite well and take and hold a nice edge. I believe mine are carbon steel. They rust much more readily than any of my other chisels. I really have to watch them.

[george wilson]

My set of 1965 Marples chisels have always been fine. They are quite hard. I tested them years ago at work,and I think they were at least 58 rockwell C. I think 60 is too hard. I'm pretty sure that years ago I read that Marples were made of 01.

The reason I think 60 is too hard is that my books on hardening steel state that 60 is really pushing it for edge retention. The microscopic edge breaks off tools that are too hard,and they seem dull due to that. Also,I made a knife from 01 years ago,and drew it to 60 RC. It never would hold an edge at that hardness.

In many years of using hand tools in Williamsburg,I found that the plane irons which seemed to keep an edge the best were BARELY fileable with a new smooth cut Nicholson file. This means that the iron had to be no harder than about 55 or 56 RC. These plane irons I refer to were antique,laminated old blades. They were then simple,water hardening W1 type steel. This was the only common tool steel widely available in the past. Better grades of tool steel were known,like Wolfram in Germany. It had a natural content of tungsten. The English steel in old English plane irons was just W1 type,though.

[David Weaver]

There was a flexbar or some brand of benchtop hardness tester on CL here a couple of weeks ago for $150. It's gone now, i'm sure someone bought it. It'd be an interesting device to have, but the fun would wear off as soon as you tested a few things, and then you'd wonder what to do with it (though I could use something like that to test irons that are heat treated in the open air).

[george wilson]

I want to get a good hardness tester for home,but used ones that work seem to be hard to find. I bid on 1 for $300.00 from a machine dealer on Ebay. They wanted another $300.00 to ship it!!

I got the Versitron for $50.00 from Federal Surplus(for the museum). They didn't know what it was!!!:) It is one of the finest units made,and cost several thousand dollars. Even came with test blocks. I had to buy a new diamond for it,which (years ago) was $120.00.

Bargains anymore at Fed. Surplus had gotten FEW and far between. They usually wanted big bucks for rusty bandsaw blades of unknown length,etc.. They let 2 piles of white pine shelving rot into the ground outside because no one would pay their high price. That's what happens when you have unqualified agents setting prices.

[Mike Holbrook]

I frequent knife making forums as well as woodworking. The people on these sites insist that the Rockwell hardness test is a very poor scale for judging how well a steel will stand up to abusive tasks like repeatedly cutting hard wood. They point to jack hammer blades as being a less hard but tougher steel. They say that very hard steel wears away very fast in a jack hammer blade, due to the edge constantly chipping off. They like a steel that will bend or deflect to a certain degree. Most of the knife guys actually test their knives by hacking away at wood, looking for a steel that can stand up to large amounts of this tough task.

[Fred Krow]

Very true Mike, toughness and wear resistance are not necessarily only high hardness.

This is why we have tools steels and various alloys added to the basic steel.

This link is a reference for kitchen knives however, it is similar to woodworking tool slicing wood fibers.

http://zknives.com/knives/articles/glossaries/mtlgterms.shtml

Regards,
FK

[Russell Sansom]

I just want to say that I really, really disliked the Chrome Vanadium steel decades ago. I couldn't put an edge on it and what I did, came right off. Or bent over. Hard to sharpen but softish in use ... not a combination I'm willing to pay for with a bit of rust-resistance.

And, I also have both Blue and Boxwood Marples chisels from the mid-70's. The boxwood-handled ones were my primary chisels for a lot of years building musical instruments and furniture and they have always taken a good edge much like any decent high-carbon steel. Compared to good cast steel, A2, and well-crafted high carbon, I'd give them a B+ for in edge retention.

The Blue handles refuse to hold a low angle of the paring kind, tending to fracture. Apples to crab-apple comparison, perhaps, but I suspect MY blues are too hard in general.
I would have to guess that the two chisels were made in different buildings, by different work groups, or something like that.

[Johnny Kleso]

Chrome Vanadium steel is always good to see when buying wrenches but its hard know how good a cutting tool is when you buy it..

[george wilson]

It is true that hardness is but one factor in edge retention. Alloy is also very important. As I said,I always found on antique irons that those that I could barely cut a little with a new smooth cut file held their edges better.

A smooth cut file will file harder steel better than a coarser cut file. If you ever wish to test hardness,do use a new(or file that has NO shiny teeth on the part you will use),good American made Nicholson file. Other good files like Heller used to be made in USA,but Nicholsons are the most common to find. If you can barely file a plane iron in plain carbon steel,it is about 55 RC.

Since I am still making punches and dies for our jewelry business,and other tools,I hope I can find a good hardness tester,though after many years you get to where you can pretty well judge what hardness you have produced. In punches and dies that are difficult to make,and which will produce many thousands of punchings,it becomes even more important to get the very optimum performance out of your steel.