Thread: Chisel Hardness Study, the first step.

Originally Posted by Bushmiller

TJ

File steel is excellent steel but of course extremely hard and very, very brittle. It also has an inherent problem in that the file's teeth create stress lines. You may already be well aware of this failing, but whenever the subject arises I feel the need to remind people including those who read these threads. There have been some horrific accidents involving chisels made from old files, although it is true to say that these have usually been turning chisels rather than bench chisels.

Even in a bench style chisel it will be necessary to grind off all the teeth and even this may not remove all the stress faults. Of course, if you are just doing a test for comparison purposes and only gently paring it is probably not unsafe. However the step to recycling old files for other uses is not a large one.

Regards
Paul

Paul - you have saved me from having to jump in immediately to make the same point, thanks.

Fellow woodturners: We know that our turning chisels/gouges are subject to very high lateral forces with the tool resting on a hard metal fulcrum point (the tool rest) and the tool tip overhanging the rest. As Paul points out, turning tools that have been re-purposed from old files are dangerous. The consequences of a tool that is too hard and brittle can't be over emphasised. I won't let anyone I'm teaching or supervising have them in the turning workshop.

There may be exceptions where a skilled tool smith can temper old files down to be less brittle, but that still leaves the stress cracks that may remain (from the original stitching of the file) after grinding off the teeth.

BTW, there is a reason why we turners stopped using high carbon steels for woodturning a long time ago. They just don't hold a sharp edge long enough for our purposes. The HSS tools that have replaced them are both very hard and tough. If you wish to get into making your own turning tools I suggest you get on top of making them out of HSS the way our fellow woodturners, Doug Thompson and Dave Schweitzer, have done. They make excellent HSS woodturning tools. There is always room for a few more quality turning tool makers like them!

BTW2, I have nothing against high carbon steels. I like it in some of my blades and, in particular, in my kitchen knives, but not for woodturning.

Is it common in Australia for people to try to make their own turning tools? Here in the states, I've never heard of anyone trying to do it (I'm sure it's occurred often, though - there's a whole world of cheapskates here). We do have a few people who turn with vintage carbon steel tools (purpose made), but they are usually turning on a spring pole lathe or something similar, and not a power lathe.

I wouldn't be surprised if the gap between HSS and carbon steel was a lot narrower when the speed of the wood is slow, it's probably heat that's doing most of the damage on carbon steel tools.

Crack dealers have nothing on you guys.

In a couple days - the brown truck of joy will be here and I should have a few more old cast steel chisels to test out. We will see if there is something to this or not....

Originally Posted by truckjohn

Crack dealers have nothing on you guys.

TJ

You may have to explain that one to me. (I'm having a slow morning) . I'm not sure if it is a compliment, a back handed compliment or an outright castigation .

On the subject of high carbon steel tools, I have made many such tools using, primarily, recycled leaf springs from the likes of utes ("pickups" across the pond) and other light commercial vehicles. I think I have only ever bought one turning tool and that was for my son.

My justification for this apparent stingyness (think mean or that bloke from Oliver Twist... Fagin) is that I do minimal wood turning. In fact, initially the irony was that the only turning I performed was to make handles for the tools I had just made! However as time has passed I have made handles for other tools too. But I have never turned a bowl, for example. Consequently, I think I could be described without any offense as a dabbler in wood turning.

I should also add that my tool making is primarily restricted to the winter months as I use the slow combustion heater in the house to anneal the leaf springs first. Then they can be hammered flat, cut, shaped and finally re-hardened and then tempered. These latter two steps are done with hand held oxy torches as I do not have a forge.

I doubt that the commercial operations have much to fear from my endeavours, but it suits my very light use of the lathe. The tools are crude and unrefined. All they are intended to do are produce a satisfactory result for my purpose:

P1030791 (2).JPG

They live, unloved, in my open to the elements shed and as well as being crude are now rusty too. I have not used the lathe in a least six months. I cleaned up one scraper (second from the right above and in the middle below) to show they can be better and the bevels on some of the others. The ruler is 400mm (16") to give an idea of size.The large skew chisel is the epitome of function as opposed to aesthetics. It was heavily pock marked from rust and twenty five years beneath an old Toyota truck, but the bevel grinds up to clean metal.


P1030792.jpg

These are some tools that have not yet been completed:

P1030793.jpg

And some more mini lathe tools made from high carbon round bar: Also uncompleted.

P1030794.jpg

As I said, not a pretty sight, although they could be "fancied up" as an American friend of mine describes the beautification process.

But I digress slightly .

Regards
Paul

Originally Posted by D.W.

Is it common in Australia for people to try to make their own turning tools? Here in the states, I've never heard of anyone trying to do it (I'm sure it's occurred often, though - there's a whole world of cheapskates here).

Probably about as common as people in America being arrogant and condescending - in other words, there are some who do, but most probably don’t do it much.

Although just about anyone I know who’s turned a fair bit will have ground a scraper or two into a custom shape, and often made scrapers or parting tools from various bits of steel.

How did we end up on turning tools anyway? This is a bench chisels test.

Anyhoo.... I recently fell off the wagon with respect to buying old tools.. I have sworn off it too many times now...

but for 3 in a row old octagon bolster cast chisels (a Buck, a Moulson, and a Robt Sorby) - all are harder on average than regular chisels today....

I wonder if some of this has to do with the current relevant industry standards for Wood Chisels - where a very heavy emphasis is placed upon bending and abusing them without breaking and banging them on things and very little emphasis is placed upon edge life and cutting performance...

For example - a 1/2" chisel must not permanently bend or break when about the 1st 1/2" of the chisel is clamped into a fixture and a 10.5 lb load is hung off the end of the handle.... And you have to be able to bang the flat of it's back 6x repeatedly onto a lead block without any damage.... And you have to bash the handle repeatedly without damage and be able to twist it without splitting it...

But cutting? - simply a vague statement that it must show cutting performance equivalent to a fairly simple 0.9%C high carbon steel hardened to Rc 55-58 depending on the size... That's a pretty low bar on cutting performance! That's a chisel which fails all Rob's tests with the standard 25 degree bevel they usually ship with...

And when you structure all the tests to favor a softer, lower carbon, thick beefy tool with heavy side bevels which cuts poorly - that's what you will get....

I would bet money that you test a good, hard old Ward or Moulson or Buck vs the DIN spec - and it may well crack or break and fail the tests.... But it does what a Chisel is supposed to do well - it cuts... And it will stand up to "normal" expected use pretty well which includes some prying and some impact....... But you must treat a cutting tool like a cutting tool and not go whacking cement blocks or prying paint can lids or pulling nails...

I mean seriously - nobody blames the knife maker when you wring the point of your knife off turning screws....

100% agree. Give those chisels a couple of weeks of regular use and see what you think of them. Bucks have always been a tad softer than others in my hands, newer robt. sorby also. I haven't had an old robt. sorby chisel - ...well, I'm sure that's a lie, but I don't remember using one, as opposed to I. Sorby, which I have used and really like.

Moulson is also a good name.

Indeed on the standard for cutting - the high end is barely functional (of that hardness spec). The 55 number corresponds to a chisel that is generally intolerable in joinery work.

I'm not sure that many of my chisels would tolerate the load test you mention, but I wouldn't modify them to pass that and give up on their ability to cut, take very little damage, resharpen quickly and continue that cycle indefinitely.

I'm making (by hand) two telecasters, and doing some of the shaping of the body with chisels and patternmaker's gouges. I do have a router, just choosing to do all of the work by hand to get the dexterity improvement it offers.

I found the new Robt sorby chisels (the ones that gave up the ghost in rob's tests once the wood got hard) to work pretty well in cherry once I figured out what they like. They're probably 58 or so as Rob measured them. Usable, but not as good as a mid-age ward set of tang chisels that I have (those aren't incredibly hard, but I'd bet 60-61). There are chisels that will last longer in work than those wards, but there's something nicer about them in the work. How they hold up really well (just not world record well), sharpen really quickly, etc, and take a good edge without any persistence from the wire.

Their proportions are a lot like the inexpensive tang set ($125 or so with discount from hartville) of boxwood sorby chisels, and they're only slightly better finished (not the very old chisels that were finished to a super high standard, they do have some abrasive marks left on their profiles, but the profiles are delicate). .

So.. I just stopped my plywood test on the Moulson cast chisel because it's midnight and I have to go to work tomorrow......

I never really got to the point where it wouldn't cut. It's much more chippy than the others - so the edge still "feels" sharp and pares both plywood and oak fine... But it's not happy on end grain spruce...

Chisel. Grams plywood pared till it wouldn't cut right.
Aldi. 14
Marples. 14
file. 28
Moulson. 62 - and it can still pare plywood fairly easily.:. This is a big surprise to me because prior old rust chisels have performed poorly in my tests...

So the old cast chisel made it through 4.5x as much wood as the Aldi or Marples and over 2x the file chisel and still can go further - I just quit... The Aldi and Marples wouldn't really go any further... What's in this stuff???

Originally Posted by truckjohn

So.. I just stopped my plywood test on the Moulson cast chisel because it's midnight and I have to go to work tomorrow......

Seems you've been infected, sorry 'bout that.

Originally Posted by truckjohn

Moulson. 62 - and it can still pare plywood fairly easily.:. This is a big surprise to me because prior old rust chisels have performed poorly in my tests...

So the old cast chisel made it through 4.5x as much wood as the Aldi or Marples and over 2x the file chisel and still can go further - I just quit... The Aldi and Marples wouldn't really go any further... What's in this stuff???

Depends on when it was made and who was making the steel. Teeming (mixing the contents of multiple crucibles) was practiced for large castings in Sheffield. Ladle teeming, wherein multiple crucibles were combined into a larger vessel before pouring into ingot molds to improve uniformity of the ingots, started out as a US method to overcome the problems that US makers faced in quality control. If your chisel is pre-1870's or so it's almost certainly straight carbon steel and if made before WW2 it likely also is. Sheffield wasn't producing very much tonnage in the way of alloy steels until the latter part of the 19th to early 20th century period i.e. well after Mushet started producing specialty alloys. Disston for instance was still buying Mushet steel products into the early 20th century.

From a less technical standpoint than Rob's view, I can't tell a whole lot of difference between chisels and plane irons 200 years old and those 125 years old.

Of all of the irons I've bought from sheffield to make planes, somewhere around early/mid 20th century, sheffield (by feel from the irons) looks to have gone to oil hardening steel or something similar. I don't know when and have never done a real analysis. I suspect this (oil based steel) based on the wire edge that comes off of the solid irons (the attributes of the original irons went away one by one, and not in an orderly manner - the hollow cut into the back of the iron, the tapering of width from top to bottom, and of course, the lamination). The old irons are all over the board in hardness. Butcher irons soft to mid hardness, ward irons mid to usually hard similar to what we think of as modern hard, I sorby mid to mid hard, mathieson mid hardness (harder on the parallel irons). Strangely enough, the later solid steel irons (that were still intended for wooden planes) are often fairly soft, which can muddy discerning what they are since softness makes the wire edge more persistent.

I suspect your chisels are relatively plain, though. Something closer to 1095 or silver steel drill rod.

Chisels made of that stuff wear well because of the uniformity of the failure - particles are lost, but not in large fashion, so the edge loses material without developing such a blunt edge so quickly. Strange large failures (that show up as little bent up bits on modern chisels) seem less common to me on something. Generalities are hard, though, due to the lack of uniformity from one manufacturer to the next, though the old chisels do seem closer in hardness than the old plane irons do from one manufacturer to the next. I've got a couple of freres irons and dwight and french irons, and everything with those two marks feels almost soft enough to roll a burr. they make great jack plane irons and good try plane irons, but would make a crappy smoother plane iron.

Originally Posted by D.W.

From a less technical standpoint than Rob's view, I can't tell a whole lot of difference between chisels and plane irons 200 years old and those 125 years old.

Of all of the irons I've bought from sheffield to make planes, somewhere around early/mid 20th century, sheffield (by feel from the irons) looks to have gone to oil hardening steel or something similar. I

I've run across another interesting tidbit. Bessemer, crucible and open hearth steel process production rates all peaked simultaneously in the 1906/7 time frame and then all declined a bit due to world economic conditions. Open hearth began to pull ahead in tonnage output and by the other side of WWI it dominated the other processes by a factor of almost 100 to 1. The last heat of crucible steel was prepared in Sheffield in 1952.

Thus, pre1860 tools are almost certainly made by the crucible process and if the tools are American they're very likely to have Sheffield made steel in them.
Between 1860 and the late 1870's you'll likely find a mix of Sheffield crucible, American made crucible and maybe a little Bessemer steel.
Between the late 1870's and the first decade of the 20th century tool steel could be crucible, Bessemer or open hearth for those made closer to the turn of the century.
In the early 20th century electric steel making was introduced, particularly for tool steels. Various specialized electric steel making processes persist for the preparation of the more exacting alloys.
After WWI most common or simple steel alloy stuff will likely be made with open hearth steel. The Bessemer process lingered until the 60's.
After WWII many makers started to switch to basic refractory lined oxygen furnaces, the method that is still dominant. Crucible died out in the early 50's, earlier in America, open hearth apparently carried on till the 90's or so.

The brown truck of joy brought a mixed grab bag of old used chisels...

One thing I am struck by with the old chisels compared to new is how thin many of these are... It would not surprise me to find out that part of the reason they are thinner is so the old water hardening steels harden right in the industrial practice.... And going to oil hardening steels allowed them to reliably use thicker sections - which means less returns/complaints for broken chisels..

The second thing that strikes me is that some of these old chisels are quite hard compared to what we typically see today.... It would not surprise me to find out that professionals working in shops preferred the harder chisels (where they had a dedicated sharpening station nearby) where professionals working out on jobsites may prefer the softer ones (where they might well resharpen on bricks, pavers, or good looking rocks)..

It appears that at the trade off with the newer W, Cr, and V oil hardening and more industrial process friendly alloys was more difficult sharpening - and it appears they just made them a bit softer to get around that..

I think the old ones are thin because they were designed for cabinet work (and thus never hit with a 2 pound steel hammer while not held straight into the work), and nobody would've gripped chisels the way a lot of gurus do now (like a pencil). Instead, the chisels were gripped at the handle and pulled to a marked line (or walked) instead of placed like a pencil point. That kind of thing works much better with a chisel with a light blade.

Not to mention, a cabinetmaker keeping their tools sharp with a rub stone and a finishing stone would much prefer a thinner chisel.

Originally Posted by D.W.

Not to mention, a cabinetmaker keeping their tools sharp with a rub stone and a finishing stone would much prefer a thinner chisel.

One thing I noticed is that "stropping" the edges of these old chisels on a plain, uncharged leather strop (or even a coarse denim pants leg) works very well.. I have heard plenty of people talking about doing it - but never found that sort of thing particularly effective on the newer alloy chisels... It just simply didn't help anything so far as I could tell on the newer steels....

and it brings me to another thought.... Is this why we almost never find old chisels with flattened backs? Did they simply hone the bevel and then finish by rubbing any feather edge left off on a piece of plain leather or coarse cloth?