? Re Swan Mortising chisels

[Lazy Jack]

I have been conditioned to believe that James Swan made some of the most sought ofter chisels by those who collect and use old tools

Naturally, I was pretty excited when I ran across a box of old swan chisels at the Tool Barn in Hulls cove Maine a couple of years ago. They had acquired boxes of unused swan chisels and gouges of various sizes from back stock of an ancient hardware store that was closing down. I bought some mortising chisels (for ridiculously cheap) along with some handles (new-old socket handles with leather caps) and wrapped the precious bundle up to preserve for later use.

Well I broke out the 1/2 inch mortiser today and as soon as I began to sharpen that virgin edge, it it felt softer than cheese. It raised a gray slush on the waterstone a lot quicker than anything else I'd ever sharpened (except that anant shoulder plane which I threw away in frustration because it wasn't sharpenable) Every time I'd sharpen one side of the bevel, it would curl a burr onto the other side. Nowhere even close to the whitherbees, greenlees, bucks bros or even the cheap footprints! I steepend up the edge a bit (I had assumed the original bevel was correct in this unused, unsharpened chisel) and it didn't roll a burr quite so prominantly. I started to chop a mortise in a piece of maple cutoff and it actually seemed to do OK, the edge wasn't completely destroyed, but certainly not as sharp as I'd started by any means.

Is the quality of James Swan chisels overblown? Did they use a softer steel for the mortising chisels on purpose?

[Jay Greer]

I have several Swan gouges and firmer chisels in my collection and have not experienced the problem that you describe. As the factory enlarged, James did not, personally, make every tool. Which, leads me to belive that your chisels may have been tempered on a Friday close to quitting time. In addition, when James passed on, his son William took over the factory and thence to his own sons. Depending on the date of mfg. quality control may not be what it once was so far as your tools are concerned. Another point is that softer steel may have been used to avoid shattering the cutting edges of their mortising chisels on vertical cuts.
Personally, I swear by Japanese mostising chisels which, are tempered correctly for the extra demands of cutting straight through on a vertical axis to the wood as well as prying out the chips.
Jay

[John Meachen]

If you need a definitive answer it might be worth seeking an engineering shop with a hardness tester and asking them to compare your newly acquired chisels with a known quantity,maybe a chisel you trust.If you find a discrepancy of more than four or five Rockwell C you may be justified in your concern.

[Bob Smalser]

Burn the cutting edge of any chisel on the power grinder and the blue-stained area that reached 600 degrees or higher loses it's temper.

There's been more than one yahoo who instead of carefully grinding away the blue areas, got out the torch and quench to speed things up, and made things worse instead of better.

The good news is they can probably be rehardened and retempered. Swans are generally worth saving. Find someone local with a furnace who knows what he's doing.

This one is a Swan:

http://pic20.picturetrail.com/VOL12/1104763/5536778/70921478.jpg

[Lazy Jack]

These chisels have never seen a grinder - so it might have been the original temper which was bad.

Interesting Bob, the chisel in that photo has the brown-black hue of old tool steel - just like my older whitherbees and bucks bros. These swans are still silver. I wonder if the alloy was changed in later iterations.

[jacketch]

I don't own any Swan chisels but my Swan slick is one of the finest edge tools I own.

[Bob Smalser]

These chisels have never seen a grinder - so it might have been the original temper which was bad.

Interesting Bob, the chisel in that photo has the brown-black hue of old tool steel - just like my older whitherbees and bucks bros. These swans are still silver. I wonder if the alloy was changed in later iterations.

My tools are often blue because I treat the ones used outdoors with phosphoric acid and phosphate blue to impart some rust resistance.

Swan wasn't like Buck or Greenlee making chisels into the '60's and '70's when quality went south....all the Swans I've ever seen were pre-war and best quality. If they are the real deal, I seriously doubt your Swans came from the factory lacking temper.

[Lazy Jack]

So I read up a little scratching the surface of the tempering process (at least for 01 tool steel) Seems tempering steel is kinda like varnishing - lots of vodoo with a phase diagram thrown in for good measure - but the general gist is heat until (cherry red, no longer magnetic, the phase has changed to the I don't remember state) then quench in oil - at which point the steel changes to another phase which is extremely hard, very brittle and full of internal stresses. Then it is reheated (or baked) to a target temperature or some sub incandescent state to change the relative proportions of phases and determine its final hardness vs toughness. Timing, rate of quench, length of final baking time, how cool to let it get before baking, how many cycles to cool and bake is all the voodoo stuff - kinda like foam or badger hair, hot coat or cure, laying in plaids vs brushing one direction only-

SO I won't try this on my own, but it looks pretty and has the Swan emblem - It will remain the Paris Hilton of my tool box until space gets tight. Meanwhile I think I'd have better luck chopping mortises with a screwdriver!

[Ron Williamson]

It wouldn't hurt to test the hardness of various parts of your chisel with a sharp file.
Properly tempered,IMHO, means that the file should barely cut it at the business end.Moving up the body,toward the handle, it should get softer and cut like mild steel
Compare it with a 'good' chisel, just to get an idea of the way it should be.
You may be able to grind back to decent metal with little fuss and no re-tempering voodoo.
R

[Canoeyawl]

I saw those chisels there and looked them over pretty carefully. They were all brand new and my suspicions quickly went toward an out of business or fire sale, I don't think those tools were ever hardened and tempered. They certainly were not the welded steel /wrought iron chisels of the old days.
Maybe you can harden and temper them but not knowing the alloy it's a good trick. ie - water hardening, oil hardening, case hardening etc. The tempering process is also tricky you will need to harden the back and temper the front so they don't snap off.

[ssor]

An old grey head might be able to spark them on a grinder and tell you if they have enough carbon to harden. The alloy tool steels require a furnace and knowledge of the alloy.

[Lazy Jack]

To redress the edge after my first try at a mortise, I clamped a common mill file in my bench vise using it as if it were a bench stone. The file had no problem biting the steel.

Interestingly, it was the same drag on the file as when I sharpen my ax or reshape the edge on my draw knife. I reshaped the bevel to a slightly steeper pitch to see if that would offer the edge a little more durability. I then continued with the water stones and having achieved somewhat of an edge (still not the hair shaving edge so easily applied to my plane blades and older chisels) I commenced to chop another mortise. It worked OK but by the time I was half through with it, I could already bounce light off the business end.

Interestingly, earlier I had snapped a chip off the edge of one of my footprint chisels squaring the ends of a mortise I'd cut with a router. With this mortising chisel I could pry and drag the edge against the bottom with no problems.

Now I'm wondering if mortising chisels are tempered to sacrifice some hardness for toughness given that they are driven with a mallet and don't need to be able to take on and maintain a razor edge??

Maybe I'll break out my other swans and see if they're just as soft.

[Canoeyawl]

Mortice chisels do have a thicker cross section as compared to any others esp. a paring chisel which should never be struck. The strength is in the back.
The hardened part of a (good) chisel is usually pretty thin, about 1/16". Any more than that and they get too time consuming to sharpen.
I surreptitiously tried a file on them at Hulls cove, there was a box full when I was there. Any of my chisels a file wouldn't touch it, not the edge.

[Ron Williamson]

Both of my mortise chisels are laminated,so glass-like on the front and putty on the back.
R

[Lulworth]

Lazy Jack, you got it more or less right but allow me to fill in the words ...

heat it to Cherry red (= 727 degrees C) to put the carbides (cementite iron carbide phase) into solution in the "Austenite" phase
Quench to form "martensite" a hard and extremely brittle metastable phase
Reheat = temper (Temperature and time depends but lets say 350-500C for 20 - 60 min) to form tempered martensite (tempering reduces internal stresses and transforms retained austenite to make the martensite slightly less hard but not brittle). This only works for hardenable steels -- high carbon with or without certain alloying elements (Mo, Cr, V, etc)

[Canoeyawl]

Lazy Jack, you got it more or less right but allow me to fill in the words ...

heat it to Cherry red (= 727 degrees C) to put the carbides (cementite iron carbide phase) into solution in the "Austenite" phase
Quench to form "martensite" a hard and extremely brittle metastable phase
Reheat = temper (Temperature and time depends but lets say 350-500C for 20 - 60 min) to form tempered martensite (tempering reduces internal stresses and transforms retained austenite to make the martensite slightly less hard but not brittle). This only works for hardenable steels -- high carbon with or without certain alloying elements (Mo, Cr, V, etc)

But - only temper the front of the chisel, the back should remain above 58-60 Rockwell. This will involve a heat sink. (If it is an hardenable alloy - If not, you may be able to case harden the back. This can be done at home.)

[Jay Greer]

Samuri Sword smiths coat the blade with clay and bare only the surface to be tempered prior to heathing and quenching.
Jay

[Lazy Jack]

Just a quick update on the swan mortise chisel question

Under the advise from several that there is little chance it could have left the factory untempered (and hoping like hell that was true) I sharpened that cheese stick best I could and commenced to chop a mortise into some maple. By the time the mortise was 1/4 inch deep, the edge was all beat up and I was having to slam it pretty hard with a mallet to get it to shove out any chunks or splinters.

Figuring I had little to lose at this point, I filed the edge back square and blunt, I fired up the MAP gas with a flame spreader and heated it cherry red about 3/4 of an inch back from the end until it would no longer stick to a magnet then quenched it in cold water. I then stuck it into my toaster oven and set the slider all the way up to 500 degrees. I then went about something else for a while. I came back a half hour later, opened the oven door and the chisel was gun metal blue (oops!) I let it cool down to room temp then applied it to the diamond stone. It was a totally different chunk of metal - quite hard actually. Between the diamond stone and my water stones, I got a polished edge sharp enough to remove arm hairs, but it took quite a bit longer than with my other chisels.

I then commenced to chop another mortise in a piece of maple half expecting the edge to be too brittle but it withstood the chopping and prying, leaving a smooth, flat surface on the final plunge down the endgrain surfaces of the mortise.

So probably not optimal, but at least serviceable - better lucky than good