Thread: The importance of testing.

Why didn't the owner send them back to the maker?

I guessed wrong on thinking something was soft once, and right on another, and then was surprised by a third (but not terribly so now).

1) I thought I had a LN iron that was a little soft. It tested 61, but for some reason, it was more sharpenable than a later iron I had. Both were A2. They advertise 60-62 (or did at the time)
2) I had a witherby chisel that was a later long socket firmer, relatively light weight chisel. I made a handle too big for it and gave it to a friend who has clown hands. He didn't like its edge holding, and gave it back to me. It was a later made chisel and not plain oil hardening steel. He had it tested at the lab where he works on a versitron and it was 53 hardness
3) Same friend and I tested a whole bunch of things at the same lab. One thing we tested was the bevel on an iyoroi chisel, one that was claimed to be 64 hardness. It actually averaged 61. I've got other chisels much harder, I was surprised at the time because of its claim (all of the branded japanese chisels claimed 64-66 in the japan woodworker catalog). I've come to prefer japanese chisels that are slightly less hard than their advertising claims, because they can be sharpened a lot more quickly but they still hold their edge like a very high quality western chisel plus a little.

As far as being a customer, I don't care if a maker's products are all perfect. I do care if they're not and they refuse to service them.

Whatever your views on the necessity of extreme hardness on an edge tool I guess HRC 30 is just not going to cut anyone's mustard (so to speak). As implied, the manufacturer of these should be quite embarrassed and one would hope, prepared to replace, whilst they take up the issue with their steel supplier...?!

There's a lot for (amiable ) discussion on the topic of hardness in cutting tools. Years ago, I was constantly searching for harder & tougher steels for my cutting edges, convinced there is some magic combination of hardness & toughness afforded by some alloy or other that would be easy enough to sharpen but hold it's edge forever in any situation. But I've pretty-well given up & accepted that there is no holy grail in tool steel, only a series of compromises, and we each eventually gravitate to what suits us best for particular jobs we do.

One of the things that set me wondering was acquiring a set of Australian-made ('Titan' brand) firmer chisels some time ago. Compared with LN A2s, for e.g., these things would be classed as 'soft'. I don't know what their actual HRC value would be, it would vary by a few points I think, & my guess would be somewhere around the 57-59 mark, maybe? But sharpened up nicely (a task that is easier to do than for A2!), all but a couple of them can be pounded into hard wood (& I mean hard) with less dramatic effect on their edges than if I treated the LNs the same way, despite their steeper bevels. At first blush, this didn't make sense at all to me, but I guess these chisels were made expressly for chopping our hard woods and they were hardened & tempered to what had been found, empirically, worked best. I've also discovered that several old well-regarded brands of chisels I have are soft enough that I can file the edges (just!), yet take & hold an edge quite well, whilst a couple of newer chisels (of a well-known brand) I've had, that seemed similar in hardness, were close to useless & turned up their noses at the slightest provocation. I keep one of them for digging out nails in recycled wood, for which is is quite useful - it doesn't chip as severely as a harder chisel does if it accidentally hits the nail & thus easier & quicker to grind back to a semblance of 'sharp'.

I still have a lot to learn about steels & cutting edges & not nearly as much time left as I've had, so keep talking, I'm listening!

Cheers,

The second of the two chisels I tested was provided to the owner by the manufacturer because the first wouldn't hold an edge. It proved to be soft too.

Today, while opening up shop, the second chisel made a break for freedom and ended up on the floor. It broke relatively cleanly along the line where the blade (D2) had been welded to the shank and bolster (reportedly mild steel). I'll try to TIG this back together using Certanium 707 (their super alloy rod).

busted chisel shank.jpg

busted chisel blade.jpg

Oh my.

I can only think of one make that looks like that, and I have one of their chisels (used to have the entire set). Normally, I'd say "who would buy a D2 chisel in the first place?" but I've found the OB mortise chisels to be very nice to use.

Ray Iles. https://www.toolsforworkingwood.com/...ls_by_Ray_Iles

So, at least on paper, where is D2 supposed to fall on the commonly used woodworking blade steel spectrum? Is it somewhere between A2 and M2? Harder than M2?

Originally Posted by IanW

Whatever your views on the necessity of extreme hardness on an edge tool I guess HRC 30 is just not going to cut anyone's mustard (so to speak). As implied, the manufacturer of these should be quite embarrassed and one would hope, prepared to replace, whilst they take up the issue with their steel supplier...?!

There's a lot for (amiable ) discussion on the topic of hardness in cutting tools. Years ago, I was constantly searching for harder & tougher steels for my cutting edges, convinced there is some magic combination of hardness & toughness afforded by some alloy or other that would be easy enough to sharpen but hold it's edge forever in any situation. But I've pretty-well given up & accepted that there is no holy grail in tool steel, only a series of compromises, and we each eventually gravitate to what suits us best for particular jobs we do.

One of the things that set me wondering was acquiring a set of Australian-made ('Titan' brand) firmer chisels some time ago. Compared with LN A2s, for e.g., these things would be classed as 'soft'. I don't know what their actual HRC value would be, it would vary by a few points I think, & my guess would be somewhere around the 57-59 mark, maybe? But sharpened up nicely (a task that is easier to do than for A2!), all but a couple of them can be pounded into hard wood (& I mean hard) with less dramatic effect on their edges than if I treated the LNs the same way, despite their steeper bevels. At first blush, this didn't make sense at all to me, but I guess these chisels were made expressly for chopping our hard woods and they were hardened & tempered to what had been found, empirically, worked best. I've also discovered that several old well-regarded brands of chisels I have are soft enough that I can file the edges (just!), yet take & hold an edge quite well, whilst a couple of newer chisels (of a well-known brand) I've had, that seemed similar in hardness, were close to useless & turned up their noses at the slightest provocation. I keep one of them for digging out nails in recycled wood, for which is is quite useful - it doesn't chip as severely as a harder chisel does if it accidentally hits the nail & thus easier & quicker to grind back to a semblance of 'sharp'.

I still have a lot to learn about steels & cutting edges & not nearly as much time left as I've had, so keep talking, I'm listening!

Cheers,

Ditto that entirely. New chisels vs. old chisels and all.

George Wilson often talks about ideal hardness being something that can only just be cut by a high quality vintage single cut file (that's somewhere in the very high 50s, I'd guess).

I tend to agree with that. It's not something that a test of the most feet of shavings would find to be best, but in terms of desiring edge uniformity and only sharpening wear rather than damage, it's just about perfect.

I'm sure the old buck chisels can be filed (they're the softest ones I have that I can think of), but they are exceptionally fine grained and can be used well given their hardness.

Originally Posted by D.W.

Oh my.

I can only think of one make that looks like that, and I have one of their chisels (used to have the entire set). Normally, I'd say "who would buy a D2 chisel in the first place?" but I've found the OB mortise chisels to be very nice to use.

DW; I am assuming OB stands for Old Bucks.

Originally Posted by planemaker

DW; I am assuming OB stands for Old Bucks.

Oval bolster. Iles is the one I was thinking of, of course. Since you named them. Mine have been exceptional to use, but I've not had good luck finding lots of vintage OB chisels. If the ones RI is selling were solid D2 with a broached bolster slid onto them, they would be better, I suppose. It never occurred to me that they would be welded to a mild steel tang, but I've never seen anything other than the wooden handle break on them, either.

There has been some trading of brands in the UK lately (clico, etc), but I don't think it has anything to do with the Iles chisels.

DW; I am guessing Iles chose to use a mild steel tang because D2 ranks very low on the Impact Toughness Scale.

Crucible Tool Steel and Specialty Alloy General Information

Originally Posted by planemaker

DW; I am guessing Iles chose to use a mild steel tang because D2 ranks very low on the Impact Toughness Scale.

Crucible Tool Steel and Specialty Alloy General Information

That's possible. From that chart, I can see why Bill Tindall and Steve Elliot chose 3v to make chisels.

I think a lot of it with RI would also have to do with production cost - to broach a mild steel bolster to the right size and fit it over a D2 tang and then fasten it without damage would probably be a lot harder than making the whole assembly from the bolster back separately and out of mild steel. It just seems confusing that it would be done that way. Even if hardness was an issue, it could be hardened differentially like old chisels were - though maybe that would be too difficult with D2.

But before we go too far down the road, I hope that Rob will confirm that it is a RI chisel or that it is not (since he said custom made, they may have been made by someone else). If RI makes them out of a solid hunk of steel from one end to another and then fits the bolster, I'd hate to have people thinking otherwise. Mine have been a delight to use, from how well they hold an edge (yet still sharpen quite easily on waterstones) to the way they tapered the end of the chisels so that they're not too fat in a mortise.

Yes, they are Ray Iles make. The story goes like this.

A guy I met at one of the LN hand tool events called me up and explained that he had two mortise chisels that wouldn't hold an edge and he asked me to test their hardness. He received the first chisel and found it wouldn't hold an edge. He contacted the seller and got the second chisel but it also wouldn't hold an edge. He explained that he had the full set of mortise chisels but only the 1/2" chisels were giving him problems.

About a week later they arrived and I tested them using the 150kgf Rockwell C scale tester I have. I had just calibrated it because at the time I was testing my hammer faces. The first chisel, that I marked #1, gave hardness readings between 30 and 32. The second chisel was 34-36 depending on the area tested and I tested from as near the cutting edge as possible all of the way down the shank of the blade to the bolster. I passed the information on to the owner and asked him what he wanted me to do next. I tried sharpenining the chisels to get a feel of them and it was rather like pushing a bar of soap along a concrete sidewalk - they were very obviously very very soft. So soft I'm surprised that it wasn't noticed when they were being ground and sharpened before being shipped for sale.

Then I proceeded with the first phase of the series of hardening experiments I described in the first post. I passed the information back to the owner and he replied telling me that he had contacted the seller who had been in discussions with Iles. The responses were:

It's impossible to get hardness readings because none of the surfaces of the chisels are parallel and the indenter can't therefore be applied perpendicular to the tested surface. Not a problem, I tested the sides that were nearly parallel and on the front faces first, then I leveled out the surfaces using machinist wedges. No real difference was found in the readings, 30 ish can't be mis-interpreted.

The tang and bolster are mild steel, they shouldn't be hard, only the blades are D2, the tang and bolster are welded to the end of the blade. Yes, it was very clear after the first heat cycle that the bolster and tang are mild steel. In addition the weld line, previously invisible, was very evident due to surface oxidation/etching that happened during the heat.

Some kind of problem with the heat treating oven was mentioned, a leak or something, and later I was told that the chisels were being heat treated by a professional third party. I was also told that roughly 10% of each batch are tested after heat treating, funny that.

I proceeded with additional heating cycles as described above until the water quench that cracked them. The chisel that broke was cracked in this area before it fell on the floor.

But again, I must emphasize that the point and purpose of my post is to highlight the importance of testing because 'feel' is a very poor substitute for instrumental methods. Hardness testers aren't very expensive and using them isn't difficult. If you're making and selling things that should be hard you'd be wise to test them.

Okay, time to close this story.

After all of the above gyrations followed by an 8+ month cooling-off period I got back to these chisels.

Today was a "welding day", that is a day where I finally get enough welding jobs accumulated to justify dragging out my welder, setting up and burning steel all day. First thing I did was finish up a heavy duty fireplace grid for a friend.

Next I picked up these chisels. I switched wire to 0.030" Certanium 707, better known as AWS 5.14 ERNiMo-3 which is one of the weld-anything super alloys. Yield strength of the weld deposit is reported to be about 120 ksi and it's priced at about $2000/roll. (I didn't pay that of course, my roll cost me $63+ship off of eBay a couple of years ago.) I figured that it'd be up to the job of holding the mild steel shank/bolster assemblies of these chisels to the supposedly D2 blades. 180A @ 19VDC with 100% CO₂ at about 5 l.p.m. and electrode positive.

Here's the chisel that didn't completely break during quenching. It was severely cracked at the blade/bolster joint. It is also cracked down it's length on one side.

misdom chisel before welding.jpg

I ground out the crack about half-way through the body of the blade all the way round.

misdom chisel grooved.jpg


A quick series of beads, holding the sharp end in the vise to keep the edge temper.

misdom chisel freshly welded.JPG


I'd forgotten to bring a pan of cooling water out so, thinking fast I snatched the hot blade out of the vise and dropped the sharp end into one of my mosquito traps to protect the temper of the edge as the shank and body cooled in air.



misdom chisels in the mosquito trap.JPG


After much grinding, filing and sanding here they are made whole.

misdom chisels finished.jpg

Final hardness about a centimeter back from the cutting edges were 55.8 and 56.9. Not too bad but still not as hard as D2 is supposed to become on quenching in air. I think these particular chisels are some kind of air-hardening alloy, but they don't behave like the commonly used D2 or A2 alloys. I suspect that there was a mix-up at the alloy supplier. Iles told the customer that he spark-tested the stock and it was D2. This assertion highlights another facet of the need for testing - you really do need to check your materials to be sure that they are what you think they are. This can be done directly using something like XRF or much more practically by requesting documentation for your material lot from suppliers.

When I was doing the HT above the maximum hardness I could get out of these things was about 49, even quenching in oil. The last quench in water caused the cracking but at least it got them hard enough.

Now it's back to the very impatient customer.

Next task - floating shelf frames...