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Thread: Narex Chisels - Comments on use

  1. #1
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    Narex Chisels - Comments on use

    I've read many good comments here on SawMill Creek about the Narex chisels so when Gabor Siklos offered a set of 6 for $55 I decided to try them. I received them a few days ago and have used them making dovetails for the past two days.

    Gabor had flattened the backs of the chisels so I was unable to evaluate that aspect of them - but I didn't mind missing that task. Thank you, Gabor.

    I put the chisels through my standard sharpening routine, which is to grind a 25 degree primary bevel on them with a diamond plate on my WorkSharp, and then to put a secondary bevel at a higher angle on a Shapton 8000 stone. This is the same technique I use for all my chisels, including Japanese chisels.

    My normal chisels for dovetails are my LV PM-V11 chisels but I certainly did not expect the Narex to perform like the LV chisels. However, I found that the Narex dulled fairly quickly. I was cutting pine cross grain and pine requires a sharp chisel to cut it cleanly. Once the edge rolls, the wood is not cut cleanly but appears to be pushed apart. Hard to describe adequately but I can quickly tell when the chisel is not cutting cleanly.

    The Narex chisels took a keen edge and cut well just off the stone but the cut got progressively worse the more I chopped with it.

    To help evaluate my expectations, I then got some of my antique Swan chisels, marked "Best Cast Steel," and used them to compare directly against the Narex. (I had already done a comparison between the Swan and the LV PM-V11 chisels and the Swan dulled much faster than the LV chisels). I chopped a set of dovetails with the Swan, then a set with the Narex, then a set with the Swan.

    To my subjective evaluation, the edge on the Swan chisels lasted longer than the edge on the Narex chisels.

    This only evaluates one aspect of the Narex chisels, using them for chopping dovetails in pine cross grain, but that's what I wanted them for. It's also possible that I just happened to get a set of Narex chisels that were somewhat soft. But this is what I experienced with the Narex chisels that I have.

    Mike
    Last edited by Mike Henderson; 02-19-2018 at 2:43 PM.
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  2. #2
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    Narex uses a low-alloy steel. While it's not water-hardening HCS as in the Swans it's close, and in my experience it's in the same class as good quality HCS in terms of both edge taking (extremely good) and edge holding (ok). It's not a high-carbide super-steel like PM-V11, but it's also a lot faster to sharpen than any super-steel.

    One thing to be aware of is that like many pre-machined chisels the wear performance of the Narex tools improves a bit after the first several sharpenings, as you work past the surface layer of steel. Your PM-V11 chisels wouldn't have had that behavior both because of how their HT process works and because LV post-machines the surface steel off after HT.

    I suspect that if you look at "percentage downtime for sharpening" once the chisels have been fully broken in you'll find that they're very competitive. They'll still wear quite a bit faster than the LVs, but you'll also be able to bring them back into service with a couple quick honing strokes.

    BTW the "super power" of those chisels is that they are extremely tough due to the use of austempering instead of conventional HT. If you ever have an application where shock is a concern, they'll handle it with ease.
    Last edited by Patrick Chase; 02-19-2018 at 3:08 PM.

  3. #3
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    Quote Originally Posted by Patrick Chase View Post
    One thing to be aware of is that like many pre-machined chisels the wear performance of the Narex tools improves a bit after the first several sharpenings, as you work past the surface layer of steel. Your PM-V11 chisels wouldn't have had that behavior both because of how their HT process works and because LV post-machines the surface steel off after HT.
    Any estimate of the amount that should be taken off the chisel to get to good steel? I can just grind the edge back that much and try it again.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  4. #4
    Thanks for the post Mike. I'd appreciate hearing how they compare after you grind them back a bit.
    Fred
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    Quote Originally Posted by Mike Henderson View Post
    Any estimate of the amount that should be taken off the chisel to get to good steel? I can just grind the edge back that much and try it again.

    Mike
    A millimeter (40 mils) at the very most, probably quite a bit less. I'd just use them for a while and see if they improve (that's what I did with mine).

  6. #6
    I would go at the backs rather than the bevel.

    Most likely they have a decarburized layer from heat treatment that was not ground off - because they don't grind after heat treatment.

    And most likely - the decarbed layer has been removed from the bulk of the bevel - the only remaining part is the back... Which forms the sharp part of the bevel.

    So dig out your surface plate and rolls of 100, 180, and 325 grit PSA sandpaper and go to battle. Take off at least 1/64". 1/32" would be better - but yes - I do understand it's a bear for that much steel. You know it's time to replace the paper as soon as the cut slows down - and it does take a bunch... Once you get past 325 - switch back to your stones as per usual back flattening procedure.

    Then circle back around, resharpen the bevels and off you go....

    I have done this to 2 sets of chisels now in the last few days - and the difference is night and day. It's like a completely different chisel...

  7. #7
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    Patrick,
    Which contemporary chisels are austempered, and what steels benefit from that process? Or do all steels so benefit?

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    Quote Originally Posted by Bruce Haugen View Post
    Patrick,
    Which contemporary chisels are austempered, and what steels benefit from that process? Or do all steels so benefit?
    The only current maker who says they do it is Narex. The description of Berg's old process is consistent with austempering (and it was known back then) so they may have as well.

    One "tell" is that austempered tools don't etch very well, so the vendor's information is often printed on the blade instead as is true for Narex. One other current maker that prints instead of etching is Bahco, so I suspect that their chisels are also austempered, possibly at the Narex factory (that last part is a guess based on some other design features).

    Austempering is an interrupted quench in a salt bath, the temperature of which is slightly higher than the Martensite transition temperature of the alloy. If you do the same thing but at a temperature slighty lower than the Martensite transition temperature then it's called "martempering" BTW. By holding the steel at that temperature you cause it to convert to Lower Bainite instead of Martensite, which provides vastly higher toughness though at the cost of limiting hardness. Narex' Rc59 is about as high as you can go with austempering AFAIK.

    With that in mind, there are some requirements for the steel:

    1. It has to have slow enough kinetics that a molten salt bath can harden it. In other words, the steel can't convert to something else (like Pearlite) within the time it takes the salt bath to bring it down to the converstion temperature for Bainite. That rules out many water-hardening steels, such as plain HCS (10xx etc) and W1/T10, since they won't harden at all in a salt bath for any but the very thinnest parts.

    2. It has to have fast enough kinetics that it will convert to Bainite in a reasonable amount of time. You probably wouldn't want to try to austemper an air-hardening alloy like A2, because my reading of the I-T diagram is that it would take 3 hours in the salt bath to even start converting, so that's not likely to be an economical use of production tooling.

    The bottom line is that it mostly seems to be done with oil-hardening steels (a lot of hobbyists do it with O1) and with steels that are created for the purpose and that are somewhere between water- and oil-hardened in terms of speed. Narex appears to use one of the latter, per John's observation that it's too fast for oil hardening.
    Last edited by Patrick Chase; 02-19-2018 at 7:50 PM.

  9. #9
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    Thanks much for the detailed explanation, Patrick. I sure do like my Bergs, and this could be one reason why.

  10. #10
    The point wasn't specifically about austempering or alloys and whatnot - but rather so you understand that they do not do ANY grinding AFTER hardening...

    That means there will be a decarbed layer left behind.....

    Decarbed steel is mush compared with the non-decarbed steel.. And doesn't hold an edge worth a lick....

    And you must grind that decarbed layer off the back if you want to get anything useful out of the chisel..

    As to which companies are doing this now.... From the new production chisels I have received - all of them except Lie Nielsen and Veritas/LV. Perhaps Pfeil... Probably it's not a problem for them because they are grinding the decarbed layer off during production...

    But my new Two Cherries got a lot better after I really ground the backs hard. And my suspicion is that when you hear "Soft gummy German steel" in the same sentence as Two Cherries - it's a decarb problem that will be solved by an aggressive go at the back on the surface plate.

    The Aldi chisels improved significantly - I kept wondering how in the world those YouTubers were able to get so much work out of them.... Grind 1/64" to 1/32" off the back and they are a different tool....

  11. #11
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    Quote Originally Posted by John C Cox View Post
    That means there will be a decarbed layer left behind.....
    I think that "will" is strong here. Decarb happens because of reactivity with oxygen in the environment. If the heat treatment is done entirely in an inert environment, as in a vacuum furnace or inert-gas furnace, then decarb doesn't happen. Likewise there are passivating coatings that can be used to form a barrier between the carbon in the steel and the environment. Borax is the traditional solution though there are newer and arguably better options.

    Decarb is a serious issue for the "Joe Bob the MAP-torch-wielding driveway heat-treater", but shouldn't be as much of a problem for the pros. Given Narex' overall level of sophistication I would be shocked if they aren't taking measures to inert the environment and passivate the tool surface. It may be that the salt bath complicates things in some way, though, or it may be that they have a completely different surface effect in play. That's why I ignored your previous post - it assumes that they aren't taking obvious precautions, and presumes knowledge of their process that neither you nor I have.

    Quote Originally Posted by John C Cox View Post
    The Aldi chisels improved significantly - I kept wondering how in the world those YouTubers were able to get so much work out of them.... Grind 1/64" to 1/32" off the back and they are a different tool....
    At typical austenitization times and temperatures decarb extends O(10-20 mils) below the surface of the part. That's all you really need to remove.
    Last edited by Patrick Chase; 02-19-2018 at 10:23 PM.

  12. #12
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    I have a 1 5/8" Narex chisel I used last week to chop out ipe from the mouth of several planes I resoled.

    It held up pretty well, better than the other chisels I was using - several older swap-meet Stanleys or just "made in USA" socket chisels, and a 1" blue handled Marples.

    I've yet to get my hands on a Veritas PMV-11 chisel. They sound wonderful.

  13. #13
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    Quote Originally Posted by John C Cox View Post
    I would go at the backs rather than the bevel.

    Most likely they have a decarburized layer from heat treatment that was not ground off - because they don't grind after heat treatment.

    And most likely - the decarbed layer has been removed from the bulk of the bevel - the only remaining part is the back... Which forms the sharp part of the bevel.

    So dig out your surface plate and rolls of 100, 180, and 325 grit PSA sandpaper and go to battle. Take off at least 1/64". 1/32" would be better - but yes - I do understand it's a bear for that much steel. You know it's time to replace the paper as soon as the cut slows down - and it does take a bunch... Once you get past 325 - switch back to your stones as per usual back flattening procedure.

    Then circle back around, resharpen the bevels and off you go....

    I have done this to 2 sets of chisels now in the last few days - and the difference is night and day. It's like a completely different chisel...
    There's absolutely no way I'm going to grind the backs of 6 chisels down as much as 1/32". While the 6mm might not be too bad, the 26mm would take forever. I'd rather pay for chisels that don't have that problem.

    It's hard for me to believe that Narex is putting out chisels with that much decarbed steel at the back. The edges would be mush and people just wouldn't put up with that.

    As far as polishing the backs, Gabor did that and did a good job on it.

    But just as an experiment, I'd put a back microbevel on one of the chisels, sufficient to get through 1/32", and see how they do.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  14. #14
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    Quote Originally Posted by Mike Henderson View Post
    But just as an experiment, I'd put a back microbevel on one of the chisels, sufficient to get through 1/32", and see how they do.
    Don't. I've never worked the backs of mine beyond what is needed to flatten them, and they hold up fine. Many, many other people have had similar experiences.

    There are at least three reasons why you shouldn't need to do that:

    1. Decarb almost never extends that deep. The curves in my old metallurgy text suggest more like 1/100" for reasonable austenitization time/temperature (I just looked).
    2. If your chisel were seriously decarbed it wouldn't be even close to the Swan. It would be a complete disaster, like what happens if you burn a tool all the way to light gray/green. The fact that you describe a small difference between the two more or less rules out decarb.
    3. A manufacturer as sophisticated as Narex wouldn't have decarb problems to begin with, for reasons given in my other post. There are other issues besides decarb that can make the tip of a chisel less durable than the rest (thermal issues leading to grain structure changes for example) and I suspect it's something along those lines.
    Last edited by Patrick Chase; 02-20-2018 at 12:06 AM.

  15. #15

    Lightbulb

    Here would be my strategy....

    Pick the one in the pack you consider "worst".

    Pitch it into the deep freezer over night. See if that makes any difference.

    Give the bevel a good go. Grind off 1/16" and see if that improves things significantly.

    Give the back a good go. Try to get at least 0.010" off the tip end without ruining the rest of the chisel geometry. See if that helps.

    If no to all - sell the set and move on... You may have found out why the previous owner sold them...

    If at least one of these previous items sufficiently improves things - decide if it's worth it for the rest of the set... If not - sell the set and move on...
    Last edited by John C Cox; 02-20-2018 at 9:03 AM.

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