Quick review Narex "stubbies"

Re: Quick review Narex "stubbies"

Jack Dover

How much "side" do they have?

I don't have problems with Narex handles (finding it quite comfortable btw), but the only thing I want from Narex — bevels ground so that side height is minimal and they could get into dovetails' corners. For whatever reason most modern makers produce beveled firmers, that is, chisels that are rectangular in section rather than triangular. It's because sides aren't beveled, they're chamfered really.

Re: Quick review Narex "stubbies"

Jim Matthews

"How much *side* do they have?"

The 4 I have are uniformly ground, with a 1mm "land" the entire length.

That's roughly 1/32 inch.

I suppose that could be ground to a finer taper, for the last 3/4" or so.

thanks for a thorough review

Re: thanks for a thorough review

Ray Newman

Interesting review of these chisels.

Web site shows out-of-stock, but one can sign up for E-mail notification when available.

austempering - unicorn

David Weaver

austempering puts a ceiling on hardness that's about 3 points short of ideal. I had narex "parers", but nothing else from them (they encouraged me to get english parers as the narex version was very heavy).

If I still had those chisels (I recall them taking damage pretty easily paring - not game ending, but surface defect showing), I'd be buffing them, too - suddenly 59 hardness is OK with the buff over.

I'm guessing their richter chisels are a response to people asking for a harder chisel.

Parse this, please

Jim Matthews

I'm unclear what's going on here.

http://www.narexchisels.com/Narex_Chisels/Narex_Cr-Mn_Steel.html

Re: thanks for a thorough review

Jim Matthews

Taylor tools is where I bought mine.

They appear to have some.

Re: Parse this, please

David Weaver

Normal steel process...

Heat steel above a critical point (austenize/make it austenite structure - just a name for our purposes), cool fast enough to change austenite to martensite (another structure that's brittle and very hard). Temper and then what...I'm not sure what happens with martensite, if it's tempered martensite or if it turns partially into the same thing that narex is made of.

Important point is steel gets cool enough to make martensite. If steel needs high normalizing temperatures, then cryo will help convert more of the austenite (not so hard) into martensite (and if not for higher hardness, allows more forgiveness in heating because overheating doesn't result in a softer steel after quench).

We think cool is "can touch". But cooling further converts more (cryo).

-----------------------

Austempering is bringing the steel down to a certain point and then holding it so martensite doesn't form (what we're used to after a normal quench). A different structure that's slightly less hard and much more tough forms and then that's it. No tempering. Tempering and hardness occur in a two part process, not two separate processes.

higher toughness, but lower hardness, and better dimensional stability (so less warping). Apparently much easier to hit a spec at low cost, but at the cost of giving up the high end of the hardness spectrum.

....

Someone in here big on steel could answer what the difference is between the structure that austempering makes (bainite) vs. tempered martensite. I don't know the answer to that, and only know the terms above because not understanding them can result in unexpected results (as in, increasing heat before quench with steel can result in higher hardness...until increasing heat further results in lower hardness....that's a pain if you can't manage within the necessary ranges).

Re: Parse this, please

David Weaver

Just noticed that they mention at the end that they grind before hardening. This is a big money savings as there's no grinding hardened steel and a skip is ....skipped. Normal process is grind, harden/temper, finish grind as far as I know.

Grind and harden is pretty simple. Not sure how they get it to be shiny steel without being all filthy or color changing, though (that's usually removed when finishing).

tempered martensite...

David Weaver

..read about it - martensite that's tempered is described at least by some as being tempered martensite, and not converted to the same thing that Narex austempered chisels are.

There's a knife company, "Richtig", that's suspected of using this process. The guy used a couple of knives to cut through mild steel bar (not small bar, either).

The knives were hardened, but less hard than narex tools (don't do it with your chisels..hah!).

I've read the story about the knife guy before, but all of the variables and charts are TMI for me, I'm just trying to make tools and only repetition makes terms like austenite, martensite, etc, stick in my head. When I look at pictures of martensite and bainite and drawings representing the structures, they look a little too similar to me.

(the richtig guy sat on his hardening process apparently and didn't even give it away before death. That kind of mentality, I just can't follow. Not sure if he left stock for his spouse to sell or something, but nobody has duplicated the properties of his knives yet exactly. That's not magic, it just means someone hasn't figured out his process yet, and nobody probably cares).

So, just the slow quench then?

Jim Matthews

I read about the immersion in a molten salt bath, then cooling (presumably on racks) at room temperature. It sets of my suspicion that an industrial process that was broadly distributed (for auto suspension springs) was adopted and marketing glorifies the choice.

For my purposes these should be just fine - they'll never see a hammer.

They'll tolerate a hammer fine..

David Weaver

..I've learned a little because I was forced to read.

In my chisels, when the martensite is straight out of the quench, carbon atoms sit I guess at grain boundaries and make things rigid but not ductile. quenching frees carbon so that it can create iron carbides and not eliminate ductility (at boundaries? I don't know).

I saw a quote about bainite - "poor man's martensite" or "half pearloid, half martensite", all kinds of things (or pearlite - not sure what the large grain is called when metal is cooled, but it's large grains and flexible).

So, what I'm interested in this is that one of the things I can tolerate but industry has a problem with is some warping or movement. I can manipulate it after temper, or not depending on what it does, but this is no good for industry as I'm doing it by hand. Everything that I've hardened has moved a little. XHP hardly moves, AEB-L moves more (but apparently doesn't in a plate quench - I oil quenched it - that's the "other" stainless, that's cheaper than even O1 - it's just over half the cost of O1), O1 obviously moves, and 1095 and knives made out of scythe blades warp a fair amount , especially if the grind isn't as even as it should be.

But the austempering process allows hardening without much distortion, and is very consistent (which would be very nice for a spring). The narex chisels are better than the sorby chisels. I almost feel like getting some as a spoof and seeing how hard they'll get and then reselling them as "63 hardness narex chisels, non-richter - super rare!!".

I think the process that they have is great - it's just a technical limitation of 59 hardness. It's not heat and cool, it's heat, cool to a certain point and then soak at temperature - no martensite. It must be used all over the place industrially given that it's got good dimensional stability without subsequent grinding.

If you're making carbon steel knives, you can't just grind them almost to a point and then clean them up after harden and temper, you have to give them room for warping and then grind off what remains. That's expensive.

While I wasn't in love with the narex parers, I can't deny the novel usefulness of how they're making the bench chisels and how that puts $10-15 chisels in the hands of folks at a tight spec. When I heard about the richters, I figured they'd be double the cost, maybe more, as it sounds like they're using conventional process. There's no way to make the richter type at high hardness for the cost of the regular narex, and likely no way to quench and temper the richters without doing follow up grinding, but the follow up grinding can't just be mauling metal, it has to be done neatly on very hard steel and without heating the steel.

no wonder I can't tell the difference...

David Weaver

..in some pictures of bainite vs. martensite.

Sometimes it is so difficult to differentiate between lower bainite and tempered martensite that high resolution electron microscopy is required to see the orientation of the fine carbides to differentiate the two

https://knifesteelnerds.com/2018/07/09/bainite-vs-martensite/

Purely an intellectual curiosity (for me)

Jim Matthews

The proportions and clever handle design have me hooked.

Any steel that holds a reasonable edge without special tooling serves me fine.

The "cheap stuff" today is better than the crazy expensive Swan or Witherby rarities I hunted for so long. At $15 retail, what must it cost the factory to crank these out?

Re: Purely an intellectual curiosity (for me)

David Weaver

If it's more than about $5 each, it wouldn't seem doable economically. That would translate to paying something like double for that for a retailer (delivered).

I never thought swan stuff was so great (I think people like the swan). Some of the witherby wasn't that great (but it sounds like a fat old guy with a beard "mr witherby, the old english guy over there, he knows steel!). But I did have one witherby chisel that was wonderful.

I'd say the average cabinetmaker's chisel until about 1950 was better than a narex chisel, but my distaste for the slightly soft ultra tough (bainite - I can now call it something because I know more than just "narex says there's a ceiling at 59") is just steamrolled by the buffer. I'd have no issue with it now.

Once you get to the point that marples stopped checking chisels to see if they're hard, then narex hands down. To be able to make something that can be sold at retail and shipped free - add the buffer in and I can't think of any practical improvement with my file chisels over the narex in terms of edge in use.

(the website that I linked to is a metallurgist who lives local to me and has become one of the best sources for accurate information for people dabbling in steel. He's also the person who said "You might like AEB-L". I didn't think I would, but he's right, I do!).

Love the Hindustan stone!

Jim Matthews

The Hindustan stone is finer than my Lily White Arkie but cuts faster than my translucent Washita - thank you!