Thread: Chisel sharpness testing

Larrin's work is excellent. The world of knife steels strays so far away from what we use because large carbides and a coarse edge isn't really a big deal - in slicing work, it actually extends edge life to start with a coarse edge. We're doing what knife people would refer to as push cut (not for your benefits, the term is infinitely familiar to you), but it's modified on planes with some lateral forces, so there's no perfect reference, but the card machine tests like larrin does are a good proxy and the charts about toughness and wear resistance charted against hardness give us really good ideas about what we could try.

And then on top of that, the grain pictures help us figure out what we could use or not use. A steel that has 25 or 40 micron carbides in it is never going to work for woodworking ,it would be chip fest. In a knife that's got a 400 grit edge, it makes no difference because the edge is already rough. Larrin's pictures of AEB-L under the scope, his comments about it being easy to sharpen, the wear data that it wears longer than what we typically use and then the chart of hardness for heat treat.......totally invaluable.

The fact that he has a PhD and at the same time, has the practical background to see and do things at the knife maker level is great.

He probably lives a couple of miles from me (I'm not the kind of person to meet up with people, especially people who look like they're busy - but strange that he's done all of this work local to me and I've never heard of him). Just much appreciate the data he's published - the parts of his chart that are kind of pedestrian for knives are potentially very useful to us.

His blue super tests and micrographs remind me of a tsunesaburo blue super plane that I had years ago. I hated it. IT would get random large chips in the edge and I gave up on it.

In his micrographs, he shows that there aren't that many large free carbides in blue super, but they seem to form in big sparse carbides. Which both makes an edge prone to chipping and does little to nothing to improve wear resistance in cutting (my words, not his - metal to metal large surfaces, the bigger carbides might help). Now I know why that blue super plane was a waste of time. Knife people would generally not have an issue with big carbides leaving here or there - the damage to most knife apexes is usually way beyond that.

The fact that blue super was or is marketed as something to be used on hard or abrasive woods is dopey, though - it chips right away when challenged. Something with reasonable toughness at high hardness and quick to sharpen makes far more sense.

Originally Posted by D.W.

This should be a !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Those irons cost $2.99 and you can sharpen them just by looking at them and squinting. The buffer cannot form a wire edge, so that issue is gone. It also cannot keep a crisp apex, so that is gone. What i can do is make a rounded apex that is steep but very fine at the edge.

I hate to say it, but the $2.99 iron with modified geometry is better at cutting tough woods than any high priced iron I've ever bought.

Any chance of advising where this $2.99 stuff might be bought?

I'm making a number of small planes to help with the making of cups and barrels. They will use japanese-style kanna, but long and curved (like fat paint brushes), fitted with blades not much bigger than ones thumb or a postage stamp.

Being able to make the blades myself would be a huge boon.

The blades were sold by home depot here. They were very soft (alternating origin stamps of "made in china" and "made in usa" on the packages, suggesting they were Chinese origin mostly and the stickers alternated some when standards changed).

They are NLA in the US at home depot (the comedy of them becoming discontinued is that people are trying to sell them on ebay at vintage stanley iron price now - no clue if they're having any luck. The block plane irons were $2 at home depot and the #4 sized irons were $3).

To make small irons, what you really want is precision ground annealed O1 stock, a small torch and a vegetable oil quench. It's easier than dealing with hardened irons and attempting not to threaten their temper. I have made a lot of irons with no special tooling. Probably 100 by now. hacksaw, files, sandpaper lap and drill press.

The real reason I brought up the buck brothers iron was in how drastic adjustment of edge geometry is in terms of handling difficult wood. We're often led to believe that we need special steel, but special steel sharpened with a honing guide won't stand a chance against a buffed cheap iron in really difficult wood. The cheap iron itself wouldn't stand a chance of holding up well in much at all if it didn't have the modified geometry.

Originally Posted by woodPixel

Any chance of advising where this $2.99 stuff might be bought?

Im making a number of small planes to help with the making of cups and barrels. The will use japanese-style kanna, but long and curved, fitted with blades not much bigger than ones thumb or a postage stamp.

Being able to make the blades myself would be a huge boon.

WP, if you want inexpensive small blades, this is a very reasonable proposition. You'd get maybe ten small blades out of a metre, which would make it $4 per blade. Be aware that it's typical of any hot-rolled bar or plate, and covered in mill scale that takes a good deal of elbow-grease to clean off if you do it manually (as I did). If you have access to a drum sander or linisher I guess it's no problem.

I went through my travails learning to heat treat it in another thread in which I think you participated. I still haven't gotten round to tempering the two blades I brine-quenched, which are glass-hard & unusable as-is. But I quenched one small blade in canola and it came out pretty close to perfect. It wasn't as hard as the brine-quenched examples, so out of curiosity, I've been using it in this little plane I made recently: Knob replaced.jpg 20 TP2.jpg

It sharpens like an O1 Hock blade & holds its edge well; I was planing she-oak with it a few days ago and it lasted as long as I'd expect a properly-tempered O1 blade to last (which isn't very long, of course, that stuff tests any blade!). It was a pure fluke that it came out like it did, I suspect either the oil isn't pure canola (it was the cheapest 'canola' I could find at Woolies), or the volume I used was sub-optimal, or something. I'd rather the process was more predictable & consistent, so someday when I have too much time on my hands I'm going to see if I can sort it out better.

If you want a steel that comes nicely ground but costs considerably more, then go for O1 gauge plate as D.W. suggested. My very limited experience with O1 is that it's easier to fully harden (seems to be more forgiving of what oil you use) so you will need to temper. I've bought O1 from this mob (which I've used for making plane soles & sides as well as blades) & they have always delivered promptly, though their stock comes from Britain, so no telling what the situation is in our current virus-blighted world....

Making blades is dead easy, but being able to consistently harden & temper to highly predictable levels of hardness may take a while to master.....

Cheers,

And there you hit the nail on the head Ian.
The selection of steel type from 01 to PM V11 and form - sheet to precision ground stock and hence cost. Available tooling - handtools to CAD. After selection you'll then need the data sheet for the metal, there discovering whether your shed can provide accurate heating to critical temperatures, appropriate quench medium, available cryogenics and tempering device. Sorry to show the complicated side to this but anyone thinking this can be done quickly and without failure is headed for disappointment. L-N, Lee Valley, Stanley and Sandvik employ metallurgists, have all this equipment to hand and price accordingly. Temperature variations of C25 at critical can ruin hardening, quench at undesirable rate can too, the use of sub-zero soaking might mean significant difference in hardening and time/temperature variations in tempering can also vary your end product. Warpage is another concern.

Experience obviously makes a huge difference. Years reading temps by eye, refining equipment, gathering test equipment.

Read a lot before committing and wherever you can, employ scientific and engineering standards to process and controls. I decided to buy from people who specialise and have been reviewed because the cost of doing the above was too great.

But, you can always wing it and see how it goes,

S

Originally Posted by Stocker

.....But, you can always wing it and see how it goes......

Stocker, p'raps that's the essence of being an amateur vs. doing something as a business. As amateurs we can afford the time & provided the materials are relatively inexpensive, it doesn't matter too much if our results are a bit hit & miss. If hits outweigh misses it's just part of the fun. I come from a science/research background where measuring, weighing & recording were essential daily fare. It's the only way to achieve any sort of repeatability. But as you imply, the cost of the sort of equipment & measuring gear needed for high repeatability in heat-treating a range of steels would be way beyond what any amateur could bear, so winging becomes the default method.

There's another aspect to consider & that is, does every blade you make need to be at its optimum hardness/toughness point, or can you accept something a little less than "perfect"? I suggest that much of the time we can, depending on what the blade will be used for. A blade that is reasonably close to its optimum point for that alloy is probably capable of 99% of the performance of the "perfect" one. If you mostly work with "sensible" woods, you'd probably never pick the difference.

You can buy very good blades at quite reasonable prices (or pay several times more for one that is marginally better), so if getting the planes you want to make put to work is your primary goal, that would be the simpler (& quite likely cheaper) approach. Making your own makes more sense if you cannot get something ready-made that will do the job, or if you just want to play about making blades...

Cheers,

Apologies for pulling the thread off topic. I saw a comment and it intrigued me. My needs are meagre and better asked elsewhere!

I must admit that I bought myself a couple Narex Richter chisels to try out as a Christmas Present... Haven't gotten the chance to try them out yet. I have this suspicion that they will shake out in-line with my other premium chisels. I should probably already know that, the makers aren't dumb, so they know where they have to shake out.... But, well, I'm a sucker.

The mystery to me in the testing he presented was Two Cherries. I've always gotten excellent performance out of them, on par with my Pfeil, Ashley Iles, and better vintage chisels. My own ranking would downgrade my Two Cherries because of excessive preparation required on new chisels, and handles I don't really like all that much. But once the prep is done, it's done... They cut as well as anything else in their price class. I wish Two Cherries would offer a set that's correctly flattened and London Pattern octagon handles... But it's not to be.

Otherwise, it went like I expected... The good stuff mostly shook out in one group on top, the mid tier stuff in a second group, then the dregs at the bottom.

As usual, preparation and sharpening had a much larger effect than brand, but given "the same" preparation, the good stuff usually does better.

I've done enough making and experimenting to boil things down to simpler terms - I know that sounds arrogant to say that, but what I've found is this:
* chisels that are kept around the 62/63 hardness range will always fare better (and seem sharper) chopping at a given edge angle vs. a softer chisel. The issue is yield strength - it's higher with higher hardness
* chasing higher isn't unlimited - if strength his high but toughness is low, you get to a point where the edge can't tolerate deformation at all and chipping is the result (the japanese chisel in WBW's test is probably just overhard if the hardness data is accurate
* taking those two things above, I think you'll find the following:
- your two cherries chisels are probably harder than the ones in this test (61 hardness is drastically different in behavior vs. chisels in the high 50s - which makes it really annoying when someone gives a hardness range of 58-63 or something - they will behave like completely different tools
- if you get a narex richter in the 63 hardness range, it will seem excellent and I would expect it to go toe to toe with a very expensive chisel of the same hardness

A two step die forging process should make chisels very cheap to make - it's the finishing work that makes them cost a lot. While plane irons benefit from heavy alloying to improve wear resistance (I found both LV's make of V11 and my imitation to last twice as long as O1), chisels don't benefit from the same. Better toughness in steels with fewer carbides means adequate toughness at high hardness given the angles we deal with.

If anyone is working with chisels that aren't holding an edge well, it's probably just because they don't meet a decent hardness spec. I am just taking a wild guess here about chisels made in the hole between 1925 and 1980 or so, that a lot of those are soft because the market went almost entirely to chisels for site use, and nobody would've been very happy using an india stone on site to sharpen a chipped chisel at 63.7 hardness or whatever the richter came in at.

(I haven't looked at the WBW data set much, but I do recall seeing that the T-C chisel was below hardness spec. I had a set of hirsch (same thing) years ago and they didn't miss their spec and were fine. )

or, in short, most chisel tests are gamed to reward a certain hardness level and most "good" seeming chisels of a given brand are the ones that end up near the top of the spec. Much reputation is assigned to the steel, but in chisels, the steel type doesn't make much difference.