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Evan Smith

PM-V11 Knifes

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I have been asked about making PM-V11 knifes,

It is simple yet quite difficult,,

I was reading rave reviews about PM-V11, so  I purchased and  cut up the largest plane blade that Lee Valley had at the time,,

I have had lots of high dollar knifes from across the world, this is by far the best I have used. A benefit I have discovered is,,, instead of sharpening every time it starts to feel a bit off, I just grab my round tungsten carbide burnisher, and roll the edge back straight and away we go,,, It's totally insane how this stuff behaves. It is soft, sharpens fast and holds an edge like I've never seen,, it doesn't chip out all the time.

To Cut the Blade  (NO PICS), well that stinks!

I laid the blade on a board with a wet rag under it, used a stainless steel ruler for a straight edge, clamped it all together, and cut it with a dremel tool.

Doing it that way is probably close to nuts, but I got it done, you need a good mask and filtration for the air and lots of discs, and a spray bottle with water.

I would have some suggestions to make it about 5000% easier,,, I can describe later,,, if there is any interest.

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The Dremel Disc,,

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Got carried away with bride cutting,, sounded just like a Strad,,

 

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Evan,

I was making knives out of particle metallurgy steel that has a VERY SIMILAR composition (imho) to PM-V11. I called mine PM-X.

I did some tests that showed that PM-X holds an edge 3 times better than my O-1 steel. Also in the test was a PM-V11 blade. Both my PM-X and PM-V11 showed the same 300 % better than O1 steel. I won’t be making knives for 20 months, but Yes, PM-V11 is terrific. My article was published in The Scroll magazine, a VSA publication.

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Evan, that's a great idea.  How could you make it easier?  :)

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12 hours ago, Evan Smith said:

Got carried away with bride cutting,, sounded just like a Strad,,

 

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Interesting experiment, folding legs could catch on, and will probably adapt to any arch shape :lol:

The style reminded me of someone local, who was guaranteeing to open up the sound of peoples violins :wacko:

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Wow Evan, that looks like a lot of work, but you have created a lot of knife blanks now, and I guess even the shorter pieces could be glued into a handle to make something useful.

As you have ground your bevels on what was the top end of the blade, this must mean that the entire blade is fully hard, and made of the same material throughout? I know some blades are laminated or only fully hard at the business end.

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I must confess that I didn't have a good experience with PM V 11 steel. I have a Veritas pocket plane that I bought to plane bow blanks. Putting it simply it wouldn't cut the blank. When I checked the blade the edge had crumbled and resembled a saw. I contacted Lee Valley and they sent me a replacement. After installing the new blade, which was very sharp, I took 11 strokes with the plane. It stopped cutting and the edge was sharp on both sides where it didn't touch the pernambuco and the middle had crumbled away like the original blade. Since V 11 is the only steel that is used in this plane I bought some O1 and made a blade from it. I now have a plane that works fine and retains it's edge. So in my opinion V 11 will work on some wood and not work on others.

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That is very interesting. I have not had any trouble with PM V11 but I'm not surprised about what you say. As far as I know powdered metal technology was not developed to produce very sharp, cutting edge tools. If a super alloy steel suitable for woodworking edge tools had been developed blade manufacturers would not be contemplating using powdered metal steel technology for the purpose. The fact is the best edge tools were made by forging high carbon steel. The process was discontinued about 1930 because of cost.

 

 

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2 hours ago, Dennis J said:

That is very interesting. I have not had any trouble with PM V11 but I'm not surprised about what you say. As far as I know powdered metal technology was not developed to produce very sharp, cutting edge tools. If a super alloy steel suitable for woodworking edge tools had been developed blade manufacturers would not be contemplating using powdered metal steel technology for the purpose. The fact is the best edge tools were made by forging high carbon steel. The process was discontinued about 1930 because of cost.

 

 

Dennis,

I believe I can send a copy of the tests I did comparing my O1 blades with PM-X. I wonder if Fenwickg (above) tried increasing the edge angle, since he was cutting harder wood.

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No I didn't increase the angle which was 20 degrees on the blade. That angle works fine on the O1 steel. The best chisels I have for holding an edge are my old Addis cast steel ones. I think we are so hung up on high tech items we forget what we had that actually worked.

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Hi John. Yes, I was thinking along the lines that FenwickG might have a PM V11 blade that was faulty. But I suppose that is not likely. My impression of PM V11 is that it seems to hold a good edge for quite a while. Despite that I can detect a very slight roughness along the edge fairly quickly after sharpening, so honing angle might be a big factor. So my guess is that PM V11 does crumble a bit at the edge initially but does not degrade much after that. I don't know if that makes sense because studies seem to suggest that uneven wear along an edge of all the commonly used steels progresses fairly quickly. Without a microscopic study who knows?

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2 hours ago, FenwickG said:

No I didn't increase the angle which was 20 degrees on the blade. That angle works fine on the O1 steel. The best chisels I have for holding an edge are my old Addis cast steel ones. I think we are so hung up on high tech items we forget what we had that actually worked.

I would try 30 degrees, then 34 degrees.  Do you know about my test for sharpness? 40 wt rayon embroidery thread, attached to a 65 gram weight. 

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I also have that Veritas pocket plane, and the supplied instructions specifically warn you that the 20 degree bevel might be too fragile for some difficult woods. Also, 20 degrees plus the 15 degree bed angle make a total 35 degree cutting angle, which I would expect to be highly prone to tearing out the grain on some woods, unless, of course, you're trimming end grain, which is what the factory setup is designed for.

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1 hour ago, Dennis J said:

Hi John. Yes, I was thinking along the lines that FenwickG might have a PM V11 blade that was faulty. But I suppose that is not likely. My impression of PM V11 is that it seems to hold a good edge for quite a while. Despite that I can detect a very slight roughness along the edge fairly quickly after sharpening, so honing angle might be a big factor. So my guess is that PM V11 does crumble a bit at the edge initially but does not degrade much after that. I don't know if that makes sense because studies seem to suggest that uneven wear along an edge of all the commonly used steels progresses fairly quickly. Without a microscopic study who knows?

You might be interested in the science of sharp . https://scienceofsharp.com/2014/04/16/the-honing-progression/

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Hi John. Yes it is interesting but it only shows a fairly obvious progression which you would expect. I like waterstones but I use three iron (soft steel) plates, all the same thickness and diamond paste for plane blades so I can control the honing angle accurately with honing guides which run on the bench. If I keep the honing bevel narrow I find it about the fastest, cleanest method. I go down to 1 micron. I use a cotton  mop charged with chrome oxide or rouge on a tapered spindle in a bench grinder to remove any burr. I don't think I can improve on that procedure, but it is an important part of the process. All of that is predicated on sharpening a blade with a back lapped flat and smooth. I can understand why people would use abrasives on both sides of some Stanley style plane blades which are out of shape, but not on chisels.

 

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3 hours ago, MarkBouquet said:

I also have that Veritas pocket plane, and the instructions specifically warn you that the 20 degree bevel might be too fragile for some difficult woods. Also, 20 degrees plus the 15 degree bed angle make a total 35 degree cutting angle, which I would think to be highly prone to tearing out on some woods, ..

Agreed.

3 hours ago, violins88 said:

I would try 30 degrees, then 34 degrees.

Me too. I don't think I have any cutting tool which is sharpened to a more acute angle than 25 degrees, and I often break edges even at that angle.

The PM knife I got from John Schmidt is sharpened to 30 degrees, and I think it's the best knife blade I have ever used. Norfleet and I tried abusing it pretty severely (like hogging out ebony), and the edge held up better than any of my other blades.

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3 hours ago, FenwickG said:

Why bother. I have a blade that works now.

Because maybe you'd like it if you can get the setup right? :)

Here's another possibility, although I don't know if this is applicable to PM: I've purchased some plane blades where the heat treat was apparently done after the bevel was ground, and the hardness at the thin edge was vastly different than in the rest of the blade. Grinding back the blade to get rid of that messed-up portion fixed things.

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58 minutes ago, David Burgess said:

A

The PM knife I got from John Schmidt is sharpened to 30 degrees, and I think it's the best knife blade I have ever used.

+1 :)

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1 hour ago, David Burgess said:

Here's another possibility, although I don't know if this is applicable to PM: I've purchased some plane blades where the heat treat was apparently done after the bevel was ground, and the hardness at the thin edge was vastly different than in the rest of the blade. Grinding back the blade to get rid of that messed-up portion fixed things.

I had a similar experience purchasing a companies expensive flagship, diamond hardness tested chisel set.
After honing, the first time I tried these, the edges just crumbled. It looked like I'd been hammering them into bricks. I was appalled by this, they seemed to be the worst chisels I'd ever used, and I was quickly on the phone to complain.
I was put through to someone from the workshop, who explained about this post production heat treatment, and advised to grind 3mm or more from the end of the blade, to remove this brittle section. I didn't see why I should have to, given what I had spent, and they offered to do it for free and return the chisels to me.
After I got them back, they were fine and gave no further problems. Compared to old Sheffield chisels the new ones cut just as well, and hold an edge better on ebony.

I was amazed that they would send them out like this in the first place, knowing the initial edge was too hard and brittle to use. It seemed a totally retarded thing to do.
I wonder how many people have bought new blades, had this issue and just thought they were junk, when with a bit of work on the grinder it could have been the blade of their dreams.

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Presumably "Diamond hardness tested chisel set" means the steel was tested for hardness. We know the hardness of diamond. Hardness testing of steel can be done with an apparatus which involves a weight tipped with a diamond dropped onto the steel's surface. The depth of the indentation can be measured to calibrate the hardness of the steel. It is called the Rockwell test. Plenty of info on Wikipedia.

The hardness of steel is only one factor relevant to the performance of chisels or blades. The quality of the steel is  most important. I just took a look at Ebay to see what old (pre 1930 or so) cut-throat razors are selling for. These razors were forged high carbon steel made in Sheffield back then. They are asking about $US100 for them. Buyers do collect them for the sake of it, but people evidently are buying them to shave with. That quality of steel just isn't made any more, hence the price. So I'd be very surprised if any chisels made these days approached the quality of those old ones.

 

 

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1 hour ago, Dennis J said:

 I'd be very surprised if any chisels made these days approached the quality of those old ones.

You may believe that, but it's not really the case, and I say this as someone who has dealt in antique tools for over 20 years.

Not all old chisels are good, and not all new ones are bad. It depends primarily on the knowledge, materials and methods used by those making the blades.

Lots of people get great satisfaction from using antique tools, as I do myself, but they certainly aren't always superior.

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I'd be surprised if there aren't cutting steels available today which are the best ever made. There's too much money in it for there not to be, with a worldwide market for things like scalpels, production fabric cutters, vinyl pattern cutters, gasket cutting dies, production paper cutters, disposable razors, and I bet that's barely scratching the surface. I think it's just a matter of determining which off-the-shelf product is best suited to a particular application, and the most beneficial form of heat treatment.

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6 hours ago, Dave Slight said:

I had a similar experience purchasing a companies expensive flagship, diamond hardness tested chisel set.
After honing, the first time I tried these, the edges just crumbled. It looked like I'd been hammering them into bricks. I was appalled by this, they seemed to be the worst chisels I'd ever used, and I was quickly on the phone to complain.
I was put through to someone from the workshop, who explained about this post production heat treatment, and advised to grind 3mm or more from the end of the blade, to remove this brittle section. I didn't see why I should have to, given what I had spent, and they offered to do it for free and return the chisels to me.
After I got them back, they were fine and gave no further problems. Compared to old Sheffield chisels the new ones cut just as well, and hold an edge better on ebony.

I was amazed that they would send them out like this in the first place, knowing the initial edge was too hard and brittle to use. It seemed a totally retarded thing to do.
I wonder how many people have bought new blades, had this issue and just thought they were junk, when with a bit of work on the grinder it could have been the blade of their dreams.

There a number of reasons why the immediate surface area of a post blade sharpened heat treat could produce a cutting edge which crumbles or has other undesirable qualities. Even in the best protected atmosphere there will be some high temperature oxidation going on which will degrade the immediate surface and make grain boundaries weak and subject to breaking. This could extend to .0015" deep. Also the very edge of the blade will quench much faster than the interior of the blade making is more hard/brittle surface edge. This is very material sensitive. And there are a lot of other surface problems related to heat treat. All of this would advise that in a post grinding heat treat to regrind the edge to get below this surface affected area. Another metallurgical idea, the temper is very important to the quality of the steel and it also is material sensitive. One temper program will not work on all steels. All of these processes involve big expensive furnaces and hours of time to do; costs money. A double temper is required for many steels and is often desirable to make a more stable blade which will hold a good edge longer. Some will even cryogenically  cool the part after normal quench to -150 deg f. Then temper a second time. The reason for a second temper is that in the heat treat process at high pre-quench temperatures the steel is FCC structure Austenite , and when quenched does not have enough time to form BCC Ferite and forms very hard martensite; the product of high carbon quenched, rapidly cooled,  steels. This martinsite has to be tempered as it is very hard and brittle. Tempering takes a little hardness away but greatly reduces the brittleness. After the first quench some of the austenite remains,  retained austenite, and later when the tool is in use may change to hard brittle un-tempered martensite; then be a site for fracture under stress. The second temper reduces the amount of retained martensite and gives a more uniform structure of tempered martensite. If you have a blade which is too hard or brittle you could put it in your wife's oven, danger danger!! get her permission first, at around 375 to 400 deg F. for at least one hour. Then resharpen the blade. Of course this temperature may be too low for some of the more exotic steels. We tempered all our heat treated steels carburized steel once at 400 Deg.F. Once in a while we would repeat to increase the toughness and durability of the steel parts. Maybe this will help some of you in your tools and sharpening/use of them.

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