Thread: sharpening pmv11 vs o1

Clinton - you are probably going to get a different answer from everyone who responds, but here's my take.

I own a single PMV11 blade which I use in a Stanley #4. When I first got it, I worked away at it on my regular set of stones, which were: Coarse & medium diamond plates for shaping, soft white Arkansas for initial honing, & hard white Arkansas for polishing. I was quite disappointed with the results, it took far more effort than my O1 (Hock) & HSS (LV) blades, and the edge I got wasn't up to par. It wouldn't produce the silky surfaces I could easily get off my other blades. So I did a bit of reading & decided to give water stones another go, since various people were claiming they cut the harder steels faster & cleaner. I bought a 1,000/8,000 Ohishi, partly because it was touted as not needing soaking, and I didn't want all the faffing about that goes with stone ponds, etc. It does the job well, & I can finally put a nice clean edge on the PMV11 in a reasonably short time. It also handles my A2 chisels much better than the Arkansas stones.

All in all, I'm happy enough with it, but it's still a water stone & I have never liked the idea of deliberately sticking edge tools in pools of water! That said, I've had no troubles in the ~2years I've had it. I dry diligently, and lightly oil blades if I'm putting them away for any length of time.

The stone I got is vastly better than the water stones I tried many years ago. It doesn't need soaking, true, but it does benefit from pre-wetting a few minutes before use, particularly on a hot, dry day. And as a very long-time oilstoner, I'm still getting used to its softer surface. I have managed to gouge bits out of the 8,000 surface a couple of times, and it requires regular maintenance to keep it flat, though nothing like the softer bond stones of old.

For the moment, that's what is working for me...
Cheers

Originally Posted by Clinton1

could someone give me a run down on the differences between the pmv11 and o1 blades from a sharpening perspective?


O1 is what i am used to, does pmv11 require different stones, or just a different technique?

Hi Clinton

The whole point of PM-Vll is that it will outlast O1 steel. There is no free lunch. If you use sharpening media that reaches its limit with O1, then you will find PM as much of an effort as A2.

As Ian discovered, one needs to move on to using appropriate honing media. This "normalises" the effort. The question is really "what type of media is needed for PM-V11 steel?". The answer is that you can use most modern manmade waterstones. I have Shaptons, Sigmas and Spyderco stones. All work this steel with ease. Yesterday I had a visitor to my workshop, who was curious about the steel, and I honed a freshly-ground 1" chisel in 4 strokes (in total) on 2 Spyderco stones.

With regard technique, that is a topic for another time, really, since appropriate technique reduces effort for all things, shapening and building. For sharpening, I work on a hollow grind.

Regards from Perth

Derek

Food for thought when applying a hollow grind.

http://www.amgron.clara.net/page74.html

Thanks gentlemen, sounds like my current arsenal will cope fine with the new steel.
Greatly appreciated.

Originally Posted by planemaker

Food for thought when applying a hollow grind.

http://www.amgron.clara.net/page74.html

Stewie, I can't understand why there are so many discussions about a flat bevel from various bloggers, etc, desiring a "stronger" edge or wanting insurance for an edge, but the question of whether or not an edge actually fails due to a hollow grind is never asked or answered. IF it's not, then it's purely a security blanket for considered possible problem.

(I have some of each, flat and hollow ground, but have never noticed any difference in failure rate, heavy work or not).

I think that what is missing from the discussion is that there is no practical gain to be had flat grinding a chisel vs. hollow grinding in terms of longevity of an edge BUT there is a very real desire to ride a flat bevel on tools like mortise chisels where one uses the mortise chisel with the bevel facing away from the waste side of the cut.

I'm going to add an alternate opinion on V11. I had some conversation (very brief) in writing with Rob and mentioned that I'd be curious as to whether or not it could be honed on jasper (which functions as a burnisher and makes things ungodly sharp, removes all semblance of a wire edge, etc, but it's a very slow burnisher).

I've had two V11 irons, and both felt similar to me, it feels like a hard stainless steel, but very fine grained (presume due to being powder metal and finely grained).

I was able to hone a V11 iron to perfectly satisfactory performance with a washita stone, but it does take an extra 15 or 30 seconds to thin the wire edge before going to the strop, whereas thinning is quick with carbon steel.

I also found (this is the important part) that just as with A2, anything will work it just fine as long as the grinding takes into account the cutting speed of the stones used. So, for V11, that means grinding more often, but that is not a big deal. You can still get several hones on it even with a very antiquated set of stones.

That kind of thing is possibly not suitable for a beginner, but someone who grinds accurately and who has no qualms about lifting the handle of a tool or lifting off the bevel for the last work on the edge, no problem on V11 with any type of stones that I could see.

A beginner will probably have a different opinion, they will be counting on their stones to cover some sins of grinding, use (beginners manage to microchip and nick things) and honing.

In subjective use, I found V11 to be similar to A2 on beech, which is what I've used it on, but V11 is a bit finer and more chromey feeling on stones that will convey a little more than the average soft aluminum oxide abrasive waterstone. A2 can have bad habits with shallow bevel angles on chisels, though. I suspect overall V11 is a little bit better, and it should not subject anyone to the need to purchase additional stones.

I have and I like Suzuki-ya stones

https://fabulalignarius.wordpress.com/tag/pm-v11-test/

I would imagine the difference between the 4000 vitrified stone and the shapton k pro and the chosera k is probably particle size.

Particles in the shapton are 3 micron, and the same in the chosera 5k.

There is no free lunch in sharpening because all of the stones have abrasive particles that are about the same size, and the density is not that much different.

Presume that the suzuki-ya stones are not much different than bester stones, except that imanishi goes to resin bound for higher grits.

The 400 stone that is sold there is very familiar, sold by many other vendors.

Losing 8mm of stone in 6 months is an exceptionally fast wear rate for such an expensive synthetic stone.

David makes a good point about the wire edges. I find that some of the more abrasive resistant steels, such as A2 and D2, hold onto their wire edge more tenaciously. This adds time to honing. I do not experience this as much with PM-V11, which is closer to O1 in this regard (but still more reluctant to give it up). The reason seems to me to be possibly related to grain size. A2 and D2 have coarser grain (which is why they do not seem to get as "sharp"), while O1 and PM are finer grained steels.

Further, as David notes, I also do not find much (if any) difference in longevity between single bevel and hollow ground edges. It is the bevel angle that determines strength, not the way it is ground. Even PM-V11 in a BD plane at 25 degrees is not going to hold an edge as well as ground to 30 degrees. Having said that David, Rob Lee did mention to me that it is capable of being ground at lower angles (20 degrees) in paring chisels.

Regards from Perth

Derek

Originally Posted by derekcohen

... it is capable of being ground at lower angles (20 degrees) in paring chisels.....

I can see the point there - The steady pressure involved in paring doesn't (or shouldn't?) stress an edge anywhere near as much as whacking it into something hard & nasty. I've got a partial set of New Haven Edge tool socket bevel chisels that I use as my go-to parers. I've no idea of date of manufacture (it would predate me by a goodly margin, I think), but they are made of high-Chromium steel, I'd guess, by the way they've held their shine over the years, and their somewhat brittle nature. Despite that, I sharpen them at a pretty shallow angle, far too shallow to be driven into hard wood, but rarely have I had one chip. I was just thinking about it today, whilst paring some of our Eastern She-oak with my absolute favourite of the bunch, the 1" (funny how you become so attached to a particular tool ). She-oak is a wood that is pretty hard on cutting edges, but the NH held up through the job without losing more than a whisker of its keen-ness. Interestingly, the 3/4" chisel was missing when I acquired the N.Hs., and after searching fruitlessly for years for a matching one, I finally found an "Essex" which is superficially similar to the NHs, but not as fine a blade. It is also a bit softer, and doesn't hold up as well as the NHs when pushed into She-oak!

I've been a hollow-grinder all my woodworking life, motivated primarily by laziness & impatience, no doubt. The way I see it, as long as the secondary bevel is at a sensible angle which is appropriate to the task the tool is expected to do, and extends back a mm or two before meeting the hollow, the difference between that & an entirely flat bevel would be insignificant.

Cheers,

Originally Posted by derekcohen

David makes a good point about the wire edges. I find that some of the more abrasive resistant steels, such as A2 and D2, hold onto their wire edge more tenaciously. This adds time to honing. I do not experience this as much with PM-V11, which is closer to O1 in this regard (but still more reluctant to give it up). The reason seems to me to be possibly related to grain size. A2 and D2 have coarser grain (which is why they do not seem to get as "sharp"), while O1 and PM are finer grained steels.

Further, as David notes, I also do not find much (if any) difference in longevity between single bevel and hollow ground edges. It is the bevel angle that determines strength, not the way it is ground. Even PM-V11 in a BD plane at 25 degrees is not going to hold an edge as well as ground to 30 degrees. Having said that David, Rob Lee did mention to me that it is capable of being ground at lower angles (20 degrees) in paring chisels.

Regards from Perth

Derek

I bring up the grinding method because we never really see failures up into the grind, but in knives, it's a topic of interest because the profile of the knife may come in at a very shallow angle, and the user is left to decide what they're going to do at the business edge. If one leaves the grind very thin and then just puts a steeper microbevel at the very edge, the failure of the whole setup can occur further up past the edge and back into metal (as in, a large amount of metal can come out, way up into the profile grind - something really undesirable!!)

If more than just the edge is worked, and the area that is ground is strengthened a little bit, the knife will fail at the edge first before it fails up into the grind. That's a preferable thing for someone resharpening by hand (and should be preferable for any knife just for longevity).

But in tools, we never really see failure up into the grind, which leaves the discussion to go to supposition about things like the edge maybe failing because it can flex more with a hollow grind.

Were that the case, we'd all see the failures.

A testament to edge strength is often given to things like a convex hand-made grind, but the discussion lacks the point then that the final edge is at a higher angle than the previous edge, and that certainly makes a difference.

I've not personally had much luck with paring chisels below 25 degrees or malleted chisels below about 30 plus or minus a degree or two, but I'm not surprised if LV's fine grained stuff holds up a little better a few degrees lower. I mallet all of my furniture, though, and only do much paring on planes (which always ends up being hardwoods). That might explain my experience with all of the angles.

I'd love it if one of the razor manufacturers would make LV some dies for a bolstered paring chisel...though I guess that's not how V11 works when it's put together (i.e., you don't just get a block of it, heat it up and smash it).

Making paring chisels of good quality and in the same profile as the long forged bolster paring chisels that were once popular seems to be a bit of a lost art. They all look as if they're spun out of a piece of round stock now at the bolster and then ground off.

I should qualify my discussion above about oilstones and jasper, that they can be used if one learns to use them (With A2 and V11) and still get a very good edge, but it's certainly true that if someone is new to the game, a fast cutting stone or diamond paste would make more sense. I don't think I could teach a beginner to freehand V11 on novaculite and jasper and be proficient at it within a day (I guess they'd need to learn to grind accurately, too).

Certainly with V11 and A2 and oilstones, the setup communicates very clearly when it's time to grind (because it becomes like work to sharpen if you forgo grinding too long).

I have found that the garden variety waterstones that Carbatec sell will sharpen the PMV11 plane blade I have perfectly well. I use a PMV11 in a jointer plane and it gets razor sharp and stays that way for a long time.

chook - I assume you only have the one pmv11 blade?
In your opinion is it worth putting up with the difference in sharpening between that and normal steels? I ask as I'm thinking of getting a new block plane with a pmv11 blade, and it would be the only pmv11 blade I'd have.