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Thread: LV low angle jack...pmv or O1?

  1. #16
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    Quote Originally Posted by Matt Lau View Post
    I'd say that PMV11 is actually progress.

    While I'm not sure about the HAP40 in Stu's Tsunesaburo planes (don't have one), I find that the PMV11 sharpens pretty easily on ceramic stones...not as easy as 01, but easier than A2 (to me) and *much* easier than the HSS on the mujingfang planes.
    They're both progress for some uses (and users).

    HAP-40 is Toshiba's powder-metallurgy version of M4 HSS. M4 contains about 5% Vanadium, and the resulting Vanadium carbides can't be directly cut by anything short of CBN or diamond. Softer sharpening media will simply "erode" the ferrite matrix around those carbides until they fall out. HAP40's grain size is smaller than that of conventionally processed M4, which means that you can get a decent edge on Alumina as in your ceramic stones, but in my experience you can get noticeably better results with diamond (I have a set of HAP40 oire nomi).

    I decided a while ago that I don't want to muck around with diamond for routine honing in my shop, so the HAP40 chisels don't see as much use as my PM-V11 and White, and HCS/O1 ones (all of which hone nicely and easily on Alumina).
    Last edited by Patrick Chase; 02-17-2018 at 2:54 PM.

  2. #17
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    Having a selection of steels and taking a little time to compare; I buy PM-v11 on anything it comes on ;-) I still use my O1 and A2 irons but, generally just to get me through till I can touch up the PM-v11 during an activity. Easy to sharpen and better edge retention in my use.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  3. #18
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    PMV11 I have 5 LV bench planes and 12 irons. The only negative I experience is forgetting how to sharpen. As for longevity, I would guess a few lifetimes.
    Jim

  4. #19
    Quote Originally Posted by Patrick Chase View Post
    Amplifying what Derek is saying here: The things that make steels both abrasion-resistant and difficult to hone are the carbides. PM-V11 contains very different carbides than HSS, so they're literally incomparable in terms of ease of sharpening.

    A2 and PM-V11 both derive their wear resistance from Chromium carbide, which has a Knoop hardness of ~1700. That's harder than the Quartz abrasive in an Ark (~800 Knoop) but softer than the Alumina in most synthetic waterstones and ceramic media such as Spyderco (~2100 knoop).

    In my experience the most common HSS alloys in hand tools are M2 and M4. Both contain Vanadium carbide, with M4 containing over twice as much V as M2. Vanadium carbide has a Knoop hardness of ~2700, and is immune to basically everything but CBN (Knoop hardness of ~5000) and diamond (~7000). John, your bad experiences with HSS were almost certainly caused by those Vanadium carbides, and are completely irrelevant to PM-V11. I wouldn't recommend CPM-3V or CPM-10V for you, though :-).

    The other thing that comes into play is grain size. When the abrasive you use is softer than the carbides in your steel, the abrasive ends up "eroding" the ferrite matrix around the carbides until they fall out. You can actually produce a perfectly good edge that way, but only if the carbides are similar in size to or smaller than the finest abrasive that you use to hone. That's true of PM-V11 most of the time, which is why a lot of people are perfectly happy with the results they get honing it on Arks and other silicate (quartz) media. It is generally not true of A2.
    Easy-to-understand explanations on their differences. Thanks.

    Simon

  5. #20
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    I used an LN A2 iron in a smoothing plane build. It was easy enough to sharpen on my oilstones. It holds a decent edge but does require a steeper secondary bevel of around 34 degrees to gain a slight improvement over W1 and 01. (Not enough to warrant the additional cost of continuing down that track.) In retrospect, had I read the feedback by Mr Pallas that PMV doesn't require sharpening over several lifetimes the substantial cost of a full make-over would have been worth it.
    Last edited by Stewie Simpson; 02-18-2018 at 7:24 PM.

  6. #21
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    Quote Originally Posted by Stewie Simpson View Post
    In retrospect, had I read the feedback by Mr Pallas that PMV doesn't require sharpening over several lifetimes the substantial cost of a full make-over would have been worth it.
    Yeah, so about that...

    As I noted above and in other threads, PM-V11 is broadly similar to D2 but with much finer grain structure. If you see durability claims for it that wouldn't seem credible if applied to D2, then they're probably not credible for PM-V11 either. This in turn brings us to Mr Pallas' claim, which does not ring true to me based on my own experience with the steel (the vast majority of my plane irons and many of my chisels are PM-V11). It lasts longer than O1 or A2, and does so without the edge roughness and "chunkiness" that bedevils other such high-wear-life steels, but it doesn't last THAT much longer.

    More broadly, tool steel selection for Western hand tools (so ignoring shock) has always been a tradeoff between wear resistance and edge-taking. The very same carbides that make some steels last longer than others also cause those steels' edges to become ragged, degrading edge-taking and leaving tracks on the work. Processes like Hot Isothermal Pressing (HIP, the most common "PM" technology for tool steels) improve matters by "shifting the curve", such that a steel can have better wear resistance for any given level of edge-taking performance or vice-versa. That's how PM-V11 can achieve D2-like wear performance with O1-like edge taking.

    There is however no magic, and no easily-honed steel I know of that can last "several lifetimes", at least for my standards of "sharp". Some of the Vanadium-rich PM "super steels" (CPM-10V, CPM-S30V, CPM-S90V, etc) can do quite a bit better than PM-V11, but good luck honing those on anything short of diamond.
    Last edited by Patrick Chase; 02-18-2018 at 8:08 PM.

  7. #22
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    I simply mean that the iron itself will last several lifetimes not a sharpening would last that long. Someone will come up with that claim soon enough tho and will guarantee it too. They claim that for some knives now don't they.
    Jim

  8. #23
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    Plane arrived today. As a test of my willpower I put it on the counter unopened and ran a few errands and got a haircut. Lipstick on a pig, and all that.

    I was curious as to out of the box usability given that we hear both sides on that issue. I guess we'll split the difference because it fared quite well on edge grain pine and mahogany, but not so much on end grain. Poor me, I'll need to hone it. Given I've spent considerable time resetting bevels on old plane irons with sandpaper lately, I shouldn't be too bothered.

    Overall, my initial impressions are very positive. This is the first premium plane I've purchased, and.... I like it. It feels wonderful to hold and I particularly like the upright tote, even if my pointer finger had no idea what it was supposed to be doing.
    Last edited by Nathan Johnson; 03-12-2018 at 9:34 PM. Reason: I called the tote the handle. Ugh.

  9. #24
    Is steel PM-V11 similar to D2? I was quoted a high price for PM-V11 compared to D2. I was enquiring flat bars.


    Quote Originally Posted by Patrick Chase View Post
    Yeah, so about that...

    As I noted above and in other threads, PM-V11 is broadly similar to D2 but with much finer grain structure. If you see durability claims for it that wouldn't seem credible if applied to D2, then they're probably not credible for PM-V11 either. This in turn brings us to Mr Pallas' claim, which does not ring true to me based on my own experience with the steel (the vast majority of my plane irons and many of my chisels are PM-V11). It lasts longer than O1 or A2, and does so without the edge roughness and "chunkiness" that bedevils other such high-wear-life steels, but it doesn't last THAT much longer.

    More broadly, tool steel selection for Western hand tools (so ignoring shock) has always been a tradeoff between wear resistance and edge-taking. The very same carbides that make some steels last longer than others also cause those steels' edges to become ragged, degrading edge-taking and leaving tracks on the work. Processes like Hot Isothermal Pressing (HIP, the most common "PM" technology for tool steels) improve matters by "shifting the curve", such that a steel can have better wear resistance for any given level of edge-taking performance or vice-versa. That's how PM-V11 can achieve D2-like wear performance with O1-like edge taking.

    There is however no magic, and no easily-honed steel I know of that can last "several lifetimes", at least for my standards of "sharp". Some of the Vanadium-rich PM "super steels" (CPM-10V, CPM-S30V, CPM-S90V, etc) can do quite a bit better than PM-V11, but good luck honing those on anything short of diamond.

  10. #25
    PMV-11 is a bit like the powder metalurgy version of D2. The PM process does wonders with the grain size. D2 with it's very high chromium content has large chromium carbides, PMV-11 not so much although it has a similar same amount of chromium.

    It's no wonder that PMV-11 is a lot more expensive in raw form. D2 is produced in a much simpler process in huge quantities. It's used throughout industry. PMV-11 is a special steel for a very small market, I think it was first designed for the knife enthousiasts.

  11. #26
    After running the numbers. It is actually cheaper to buy from LV PM-V11 then to make your own.

    Quote Originally Posted by Kees Heiden View Post
    PMV-11 is a bit like the powder metalurgy version of D2. The PM process does wonders with the grain size. D2 with it's very high chromium content has large chromium carbides, PMV-11 not so much although it has a similar same amount of chromium.

    It's no wonder that PMV-11 is a lot more expensive in raw form. D2 is produced in a much simpler process in huge quantities. It's used throughout industry. PMV-11 is a special steel for a very small market, I think it was first designed for the knife enthousiasts.

  12. #27
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    Quote Originally Posted by Kees Heiden View Post
    PMV-11 is a bit like the powder metalurgy version of D2. The PM process does wonders with the grain size. D2 with it's very high chromium content has large chromium carbides, PMV-11 not so much although it has a similar same amount of chromium.

    It's no wonder that PMV-11 is a lot more expensive in raw form. D2 is produced in a much simpler process in huge quantities. It's used throughout industry. PMV-11 is a special steel for a very small market, I think it was first designed for the knife enthousiasts.
    What Kees said.

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