martin CH's comment on diamonds on moving MDF

[D.W.]

is worthy of looking at, though I admit, I did it a little indirectly here. The steel is just 1095 with chromium (there's a lot of wiggle room in the alloy, this is one of my more favored types because it's got enough alloying in it to make the carbon in solution just the right level. Less alloy, and 1095 is more brittle).

My point in talking about the steel being plain, though, it's more plain than O1, so I did this test with a buffing bar.

if you were going to use CPM anything with vanadium and niobium, this would be relevant for that with diamonds, as well as V11, which has enough chromium carbide volume that you're really better off using diamonds with it.

So, on to the pin up pictures:
settled in norton fine india to set the basic lower angle geometry, and then right on to MDF with a 2 micron white buffing bar. worked on the back and bevel, which left a very fine weak burr hanging on, so I alternated back and forth.

I sharpened several before this one to get the touch. It's a little harder than the buffer because anything you slip up on will deflect the edge, and the MDF on the flat side has a bit of grip . This could be made into a safer jigged setup, but good results require having fingers on the flat side when working the back, and fairly close to the edge to keep the pressure on flat but not allow the butt end of the iron to lift.

https://i.imgur.com/5iQ1j1Z.jpg

That's a pretty spectacular finish and has the bite I was referring to earlier. I will admit there were little deflections here and there of the tiny fraction of a thousandth type. When you sharpen by hand on something really fine with any pressure at all, you'll get these. When you strop, you'll remove the deflected parts, but it will take some planing to wear off the apex and get things to look perfect.

I headed over to the buffer then to see if I could remove those in about 10 seconds using the corner of the wheel. My buffing wheel is a bit overloaded at this point and needs to shed its glaze coat, so the 5 micron yellow stick was more aggressive than I expected.

https://i.imgur.com/n4eSF5L.jpg

it's possible after cutting a bunch of copper over the weekend and doing some metal grinding, that it's a little contaminated.

Interesting thing to look at martin.

So, here's a last anecdote from when I did my test. I used one of my own made O1 irons for the O1 sample, the same one pictured earlier. I was confident that it was good and actually wanted to see how good it was, but that led to some objections when I presented data ("we can't buy that"). So I was forced to test it against a hock iron to prove that it wasn't defective and skewing the results (another possible scenario provided).

Raffo has that iron now...I think. I gave it to someone. I would estimate that it's 61-62 hardness or so, but it had good sweetness. The hock bench plane iron that I had is a very good iron, but it's 64 hardness, which is pushing it.

With a very perfect tedious and light-handed sharpening finish, the very initial apex of it took a tiny bit of chipping damage even in clean wood - like you might not notice it damaged. Since the alloy is the same, hock's iron should outlast mine by 10% or so just based on hardness. I later found out the grain fineness of the hock (france) iron was very good, too - I can match it but I can't really better it. It's about as good as can be done.

What happened with that initial small damage is it took a hundred or two hundred feet of planing to wear it off back to uniform - something that plain steel irons do well. They're sort of self healing with wear whereas large carbide irons with damage will break a little bit more around the break and erode more. Hock's iron felt more crisp, it's harder. But mine lasted something like 5% longer alternating back and forth, so the feel and the keenness gave a feel different than the outcome, but I think the initial issue robbed the hock iron of a win.

5% doesn't amount to anything plus or minus, though, so the real remaining question would be whether or not it would get worse in work with interrupted cuts, and I think the answer is yes. The hock iron would probably lose all of it's hard tempered behavior with an accurate 380F temper, but I never did it and I broke it because I couldn't resist seeing how fine the grain is. they wholesale for only about $25 and the french one of my three is better than both american irons - a real dandy for a $25 wholesale.

I would expect with MDF, I could pick up a thinner shaving in a contest than with the buffer, though. It may take a couple of tries. it's certainly got merit (the moving MDF) and should someone want to actually unicorn a chisel, it takes no more than lifting the handle a bit on the bevel side.

Thanks for bringing it up.

[D.W.]

Probably also worth noting here, these pictures are optical/visible light spectrum. I could game the system by making the light level higher with the buffer picture and there is actually some detriment to having a less polished surface. The microscope sees more detail at the lower light level and doesn't automatically adjust to match because I didn't set the software to do it.

The real key in this case is observing for any rounding or defects at the edge, and then looking at the actual crispness of the edge itself. the scratches at this depth will be worn off.

I will plane something and post the picture to get an idea of the sharpness level - one can chase higher levels of finish than either of these, but laziness keeps me generally working at the latter.

[D.W.]

https://i.imgur.com/hkvwTqm.jpg

A picture of a beech shaving off of the last buffed edge. Not the greatest wood in the world for thin shavings as it starts to reveal a lattice that's fragile when shavings get really thin.

A good result, though, on an iron that's not really at the top of the hardness list.

if anyone is unfamiliar with this, there is some oil involved on the MDF to keep things both gentler and cool (for the first picture) and it should go without saying, don't do this with anything that doesn't have variable speed and the ability to run at a relatively low speed. Absent mindedness with the buffer is fairly low risk. With an MDF or leather wheel, the iron can be launched while it's in a very sharp state.

[D.W.]

how much is enough? just a little bit more. The aggressiveness of the buffer wheel in picture #2 seemed a little out of whack, but that wheel was very dirty with a fairly solid glaze forming on the diameter.

it's good to get rid of that on a buffer. It's infrequent that it needs to be done and takes about 30 seconds, but I would guess once every hundred or couple of hundred sharpenings.

A clean buffing wheel without so much filth in it results in this - the darkness away from the edge is due to the fact this one didn't see the MDF rotating disc, but rather the 2-3 micron diamond on a very aggressive chinese "ruby" alumina stone.

So india, ruby, buffer. it's around a minute.

https://i.imgur.com/vr9HyQ0.jpg

I don't think functional sharpness of the edge will differ, and certainly a buff bar much finer than my favorite 5 micron yellow can be used. The yellow is just so handy for the modification that improves chisel life drastically because it's quick.

In a bit of a giggle, the harder bigger version of the "veritas" bar is $15 for 2.75 pounds, or you can order it from LV for $16.50 for 6 ounces.

The page still calls it a 0.5 micron average scratch pattern.

Visually what it actually is on a flat surface:
https://i.imgur.com/NKvcrn7.jpg

What 0.5 micron graded abrasive actually leaves on the same substrate
https://i.imgur.com/TlmAmKM.jpg
no visible scratches - all you can see is little droplets of oil.

And what the (supposedly more coarse) SP 13k stone leaves on an edge (0.73 micron or something - very uniform, though)
https://i.imgur.com/SiPcrwV.jpg

(I did take thin shavings with the clean wheel edge - it is slightly sharper..

...and I tested 1095 iron - it tricked me. It's not abrasion resistant, so it gives the illusion that it's soft. But it's 62.5 hardness. So pushing up a level to something like 26c3, which lands around 64, wouldn't yield a much thinner shaving).

https://i.imgur.com/WqTPXhP.jpg
all three taken in a row, the one on the left is a bit thicker.

https://i.imgur.com/BGghm8B.jpg
doesn't look much different on the can - slight difference is appropriate language.

[MartinCH]

Comment for clarification


Sharpening on flat of the disc- as noted previously 2.5 micron diamond spread with oil on MDF base. The MDF base was spun a speed to "balance" the faces and the diameter.

Sharpened a couple pf plane blades just before. I do not typically use shave test for a some time, but because the process wAs new to me, I now have a couple of bare patches on my arm. Guess that's sharp.

Unlike David I have not buffed the cutting edges.

[MartinCH]

Duplicate

[D.W.]

Comment for clarification


Sharpening on flat of the disc- as noted previously 2.5 micron diamond spread with oil on MDF base. The MDF base was spun a speed to "balance" the faces and the diameter.

Sharpened a couple pf plane blades just before. I do not typically use shave test for a some time, but because the process wis new to me, I now have a couple of bare patches on my arm. Guess that's sharp.

Unlike David I have not buffed the cutting edges.

I don't use shave test any longer, either, but it's an easy test to apply. I was doing a lot of thinking through methods while I was trying these - hopefully it didn't come across as being critical. If I didn't have a buffer, I could easily get along with an MDF disc.

In my past, I did have a leather disc on a high speed disc sander that really was too strong even with the "microfine" compound. What caused me to stop using it was an instant where a blade got sucked toward the middle with friction, crossed to the other side and then dug through the leather making a deep gouge into the aluminum platen and was thrown either into the ceiling and then the floor, or the opposite. I can't remember which.

I set my MDF disc in a mandrel yesterday and used the back side because the drill press was free and the top side of the disc is one of those 10" round diamond wafers that I use to lap tools that I'm making. Thinking about it, the handy part of it is first, the drill press can run a lot slower, and second, the mandrel will prevent the "cross over" to the opposite side of the disc. It didn't feel nearly as dangerous and the difference in ease for me has more to do with familiarity, I think.

It (MDF disc) is definitely good, especially if the rough work is done ahead of time and it needs to work but a bit of the edge along with the back. 3 micron diamond is probably more sensible than 1/2 or something.

I don't spend days taking thin shavings in the shop, either. It's sort of feel indicator, though. The two thin shavings I took here look the same, but the feel was better the second time round.

I will see if they an be bettered by the MDF.

I guess you could say that I look at a lot of things under the microscope, but at this point, it's probably one a month. But it's definitely useful!

I'll scrape off the buff bar and put a fine abrasive on the MDF disc and see if it's possible to make a mark free surface like the hand lapped 0.5 micron graded chromium oxide picture above. with a clean substrate and fine diamond, you can get that optical polish by hand. it should be at least as easy to do it with a rotating disc.

[MartinCH]

Hi David

Use a 3M cubitron disc on the underside. I also used diamonds lapidary discs here as well. A 25 degree mount with camp to attach the plane blade too. This assembly is placed under the the drill press, and the low the disk to suit. It only a minor touch up. the disc is skimming with lightly on the blade. Cubitons are from experience faster than the diamond blades. The 80 or 120 grit discs cab eats tool steel rapidly. Not measured but would not be surprised if one could shorten a blade by 5mm in minute, with an 80 get cubitron. but there is risk of digging in with the higher pressure.
not I also have a clamp to restrain the mount to the bench.


120 grit it likely the better choice, as it slightly finer.

Short on bench space a buffer would take more. I could be build a slide out support for a grinder but first impressions of the moving MDF suggests a pretty good result with a slight question mark on the durability of the edge.

[D.W.]

Hi David

Use a 3M cubitron disc on the underside. I also used diamonds lapidary discs here as well. A 25 degree mount with camp to attach the plane blade too. This assembly is placed under the the drill press, and the low the disk to suit. It only a minor touch up. the disc is skimming with lightly on the blade. Cubitons are from experience faster than the diamond blades. The 80 or 120 grit discs cab eats tool steel rapidly. Not measured but would not be surprised if one could shorten a blade by 5mm in minute, with an 80 get cubitron. but there is risk of digging in with the higher pressure.
not I also have a clamp to restrain the mount to the bench.


120 grit it likely the better choice, as it slightly finer.

Short on bench space a buffer would take more. I could be build a slide out support for a grinder but first impressions of the moving MDF suggests a pretty good result with a slight question mark on the durability of the edge.

the only problem with cubitron is that it won't maintain the kind of flatness you need in chisels of this type:
https://i.imgur.com/rPmneB7.jpg
https://i.imgur.com/EeaLfaP.jpg

or bench chisels like them

However, I use cubitron or other "Ceramic" equivalents, depending on where I'm buying belts, and you are exactly right. Nothing grinds faster, and nothing cooler. Especially if lots of big vanadium isn't involved (one of the reasons knife makers don't like big vanadium carbides on finer finish knives). Diamond is consistent, but cubitron is raw skin removing power, and with a drop or two of water dripping on it, you can grind with unbelievable pressure and burn nothing.

If I took one of these paring chisels and fed it to my belt grinder, I could almost guarantee that I could grind it from end to the tang (9.5 inches or so) and make it disappear in two minutes.

pigtails of steel come off of the belt grinder and if there is a backstop close, they weld themselves together into what looks like cheap steel wool.

The way we used words sharpening and grinding is funny. These belts and discs are referred to as "Ceramic" when it's really a matter of the abrasive being stacks of micron size particles instead of big solid grits. The pile acts like one big grit but sheds and stays sharp until it's very worn. Then in sharpening stones, we see the term ceramic given to stones like shapton as if there's something unusual in them. The red india stones from the turn of the century are "ceramic", perhaps even more so if the vitrified matrix is a ceramic - the red alumina abrasive definitely is. Not to mention the scammy name given to silicon dioxide "nano coatings" for cars at $80+ an ounce. They're mostly silica like a natural stone, and not similar to alumina, but the term "Ceramic" makes us thing the film applied is like a bunch of ceramic particles like a glazed coffee mug.

I think calling that stuff graphene is taking over even though there's very little of it in the products that do even have it.

The cubitron and other ceramic belts and discs are a gift, though. At high speed they can remove skin in a way that is painful, though. fingers, knuckles, whatever accidentally may touch them - but wouldn't in the process of sharpening vs. grinding tools.

[MartinCH]

Hi David

Very nice paring chisels.

You are correct in suggesting that the disk would be a struggle to keep the steel flat. Useful for removing chips.

For flattening, I set up steel on linear slide. I have typically attached with masking tape/ glue /making tape as this sticks fairly tight and check the the intended cutting surface is parallel to the slide. Once ready the cutting is pretty quick. useful for flattening planes and chisels.
Fortunately once flat, thats done, so the slide gathers dust at the moment.

[MartinCH]

Hi All.

Used ther otating MDF disc with 2.5 micron diamonds dust and oils for the last couple of weeks. Must say I like it. It is a doodle to resharp chisels, at need. Maybe a 10 second distraction and back to sharp. Plane blade are obviously longer ( removing and returning the blade) but time on sc is similar.

I gave not recharged the disk. Does not feel to have lost any cutting power.

Regards

[truckjohn]

What happened with that initial small damage is it took a hundred or two hundred feet of planing to wear it off back to uniform - something that plain steel irons do well. They're sort of self healing with wear whereas large carbide irons with damage will break a little bit more around the break and erode more. Hock's iron felt more crisp, it's harder. But mine lasted something like 5% longer alternating back and forth, so the feel and the keenness gave a feel different than the outcome, but I think the initial issue robbed the hock iron of a win.

Truthfully, some of my favorite chisels and plane irons displayed that behavior - very low effort to get good results, and when they pick up a little defect effort stays low but in a few strokes, the defect is gone. And they go like this until they dull.

Conversely, I'm not a fan of tools that run fine until they pick up the first teeny defect, and in a few more strokes, clunk. Effort is off the charts. it's skipping on the wood and half the edge has fallen off. No thank you.

[D.W.]

Truthfully, some of my favorite chisels and plane irons displayed that behavior - very low effort to get good results, and when they pick up a little defect effort stays low but in a few strokes, the defect is gone. And they go like this until they dull.

Conversely, I'm not a fan of tools that run fine until they pick up the first teeny defect, and in a few more strokes, clunk. Effort is off the charts. it's skipping on the wood and half the edge has fallen off. No thank you.

you've run into the wheelhouse of what I've learned about tool steels. Edges should be stable to avoid defects. when they occur, the edges need to release them and not propagate a deflection and then perhaps allow it to continue to grow.

the pre-1900 tools display this.

the only question that follows that is whether or not manufacturing die lifespan requirements have some place in plane irons (abrasion resistance), and I think the answer is no - it's secondary, and it's off the table if it interferes with the main goal.

Since learning to work entirely by hand and having to actually do it, my thoughts about those things has been turned on its head. Edge life used to be choosing something with theoretically long life and then trying to get it or set up work to get it. it's sort of backwards.