I’ve had mixed results with brittle chisels and irons.

Sometimes you can put them on a very coarse stone and hog off a decent chunk of metal to get down to good metal.

Sometimes the heat damage goes a long way, and I have given up on some chisels like that.

One thing that might help is to go for a larger angle grind. What angle are you sharpening them to?

Cheers

Darren.

Try a little steeper, say, 35 degrees and take another mm or so.

Record and Marples 044 irons were made with Tungsten steel, which is a lot like high speed steels such as A2.
They are often happier with steeper angles. 30° is kind of the lower end for these steels.

I don’t think you would have much luck trying to retemper the irons, though. Hardening and tempering Tungsten steel is a bit more complicated and at higher temperatures than an easy to work steel like O1.

The good news, I guess, is a full set of irons from Ray Isles or Classic Handtools is only about £40.

That’s not case hardening. Somebody ruined the temper by overheating the tip while grinding and probably burned off surface carbon, making it softer. Your multiple attempts at sharpening probably ground enough steel to get past the ruined tip which had carbon in the steel burned off. . It likely had little to do with the sharpening angle, but if you had success, keep doing it. The steeper angle gets you past the burned part sooner.

Case hardening is the controlled introduction of carbon INTO a thin surface layer of the steel. The modern method is by heating the steel in a high carbon gas environment. The “case” is the thin high carbon layer formed over the softer core.

The ancients knew about case hardening, usually accomplishing it by heating iron in charcoal dust or any high carbon concoction including dead animals and meat, or even urine.
They didn’t understand the chemistry, which made conversion to steel a the stuff of magic dwarves and such. Ill confess I think of Wayland or Hephestius every time I see a Smith do it at a forge

Bob Van Dyke also offers a tutorial on modifying the eclipse guide

He seems a bit more aggressive on filing the flats. The goal is to make sure the irons lie flat

There are other cheap eclipse style guides that seem to have better shaped lands, but I have no experience with them so i won’t recommend any.

• This reply was modified 2 years, 2 months ago by Larry Geib.

That’s true. It also bumps the original $125 purchase to $160 plus shipping. And you still don’t know if the jaws will work with whatever chisels you own. Those jaws are only guaranteed to work with LN chisels. They will probably work with Stanley old and new 750’s, LN copied, for example, but probably not other lines of Stanley chisels. Until you try your irons, you will have no idea if they fit.
They make another set of jaws for short irons like on a spokeshave.

If you are really into boutique tooling you can add another $250 in jaws. That’s getting close to the cost of a baby Tormek.

And none of that expense guarantees your irons will fit. Lie Neilsen designs their guide and jaws expressly for the irons they produce without any guarantee they will function properly with irons made by any other manufactures. You might still have to grind jaws that alone cost twice an eclipse guide.

I found that out when I took my irons to a hand tool event. I wanted especially to be able to sharpen the iron on the skew iron for my stanley #289 moving filletster but the LN skew jaws were the wrong angle and the wrong length. (. I figured that might justify (sorta) the $150+ for an iron that is hard to get right.. I went another route.)

If you go the LN route, I again strongly urge you make sure it will work with your tools. Go to a hand tool event and physically put YOUR irons in their guide. It’s not an impulse purchase to make.

At the minimum, ask them about their return policy and know you might be paying shipping twice and end up with nothing.

• This reply was modified 2 years, 2 months ago by Larry Geib.