Hardness testing of saw plates

[george wilson]

Your tester is simply not the correct instrument for testing solid,hard all the way through steel. The Rockwell C scale is the scale to use. Your tester does not do C scale.

I have mentioned this in previous posts.

You are not the only one who has ever posted this type of data here. I have done so over a period of some years.

And yes,Japanese saws can flex. The question is HOW MUCH. Not as much as Western type saws. You can bend the tip of a decent Western saw till the tip touches the handle. It will spring back straight.

Now,I have to go make a punch and die set for my wife's jewelry making business.
'

[David Weaver]

Well so much for staying silent.
I think the word flexed and hard enough to break when applied to Japanese high end saws needs a little more massaging for clarification.

What I am saying is you are both right but some where the terms are getting messed up.

There is flexed, a little, and there is bent.

I know that Japanese saws have teeth hard enough to snap off if the filing is too aggressive for the type of wood being cut. Yet every video I see my in the know guys, like Toshio Odate, while handling their saws can't seem to keep from flexing the saw (some times quite a bit; way past five inches) to feel the spring of the blade. Call is showmanship or compulsion.

Japanese saws are all over the board in terms of hardness. I'd imagine odate knows which saws he's doing that to (the very expensive custom made saw that stan covington sent to me was very tough and could have handled flexing, but it wasn't 60 hardness - it was fileable).

The ones that are above what we normally use for spring temper (they are probably mid to high 50s) will break with a catch in wood.

They're not really comprable to our atkins type saws for two reasons:
* you can't file them with a western file of average quality (not that they're the right shape to begin with)
* you could never begin to put the same amount of flex on them that you get on a jam with a western saw, they'd just snap

[Rob Streeper]

When someone tells you that you're wrong, it's not a personal attack. When someone tells you that it appears that you don't know enough about the application of steels to tools to know that you're wrong, it's not a personal attack.

It just appears to be the case here, and I think everyone with a lot of experience with various tool steels at various tempers is scratching their heads wondering how you think you could create a saw that you can literally take the tip and bend it to the handle and have it be 58 or 61 hardness. It doesn't exist.

David, taking measurements under controlled conditions is what I do professionally. When I take measurements I do it right or I don't do it. Sawblades are not a life or death type of product like jet engine parts so what's the beef? Why so many indictments of my competence, knowledge, methods and so on?
The uniting logical failure of all of the criticisms of my work is that none of them has offered anything but opinion. No contrary references, no data sets, nothing. Another failure is that nobody has been able to tell me with any specificity why I'm wrong. If I'm using the wrong hardness scale please educate me. I have a Rockwell B/C tester in addition to the N/T tester that I've used to generate these data.
If I'm doing this the wrong way prove it to me.

[Winton Applegate]

I respect a lot of David's work and knowledge.
Though
Now that you mention it some of my Japanese pull saws have the yellow (to brown) color left on the blades to "prove" their temper process. Though not right at the teeth so much.
The Western saws are all thicker though that can be backless; they have to be because they are pushed.

I am not saying anything obviously just echoing stuff I read here. And thinking/mulling more like.

Hey . . . give that B/C tester a go and let us know or better yet take the saws to a behemoth hardness tester like we had across the alley from the community collage Adult ed welding classes I was taking while I was still going to High School. Long story.

PS: When I looked at the hand held job my thought was "that is one light duty hardness tester . . . not like the ones I am flirtingly familiar with".

[David Weaver]

Rob, I don't know anything about your tester or its application. I suspect it's not being performed correctly, but because I don't know the testing device or what the pitfalls of its translation could be (or where it could have error).

I know that the saws you tested are not 58 or 61 if they have been filed before. That much is clear from actual experience. When I harden a chisel, I check it with a file. When it is light straw, it can't be filed - the teeth of files get burnished or chipped off by something that hard, and that's without it being thin like a saw plate (which puts fewer file teeth in a cut

I have filed a dozen and a half different backsaws from the early 1800s to now, and carpenters saws from the mid 1800s to probably the 1970s, and I guess it would irritate me to see someone going elsewhere and telling everyone that disston saws are harder than 52 hardness boutique saws, same with backsaws. That is very very seldom true.

You have a technical problem with your method somewhere, but until you can even suggest as to why someone would want a saw that couldn't be filed, you shouldn't be leaning on a tool that you don't have much experience with and asserting it's correct because you have a process that you adhere to.

[David Weaver]

better yet take the saws to a behemoth hardness tester like we had across the alley from the community collage

Stan's saw was dark brown at the tang. The rest had been polished off, so I don't know where it was in hardness, but I think stan told me something like 54? I can't recall for sure. I would never have bent it back around to itself like you can do with a western saw.

[Winton Applegate]

David,
Yup . . 54 too hard to file with western files, especially most all of the curent shlock, and I never bend my saws like the showman so I think I am safe here.
That was sure a nice saw you shared with us. Gives us a bench mark for everything else.

[Steve Voigt]

I don't have enough expertise with saws to take a firm stand here; all my saws are old Disston's and I've never owned a modern premium saw. The numbers do seem high to me, and don't necessarily pass the "common-sense" test, but that's not proof.
More to the point, I think it's a little discouraging, and off-putting, when a guy does a crapload of research, posts it, and then immediately comes under withering criticism.
It would be great if someone else with a decent quality hardness tester could do some similar tests and let us know the results. Otherwise it's all just talk.

[Winton Applegate]

It would be great if someone else with a decent quality hardness tester could do some similar tests and let us know the results. Otherwise it's all just talk.

Well . . . we are not looking at a chart of numbers from him it is true but . . . George did exactly that from what he is telling us and I am sure he has no reason to bend the facts.

I think it's a little discouraging, and off-putting, when a guy does a crapload of research, posts it, and then immediately comes under withering criticism

Yes.
Though that is the risk one takes (my chip breaker rants and ultimately taking a head shot for my mistake is a good example) for doing the best one can and posting about it.

I would like every one, especially those who read but very rarely post to take more risks and post the findings. Some one is bound to learn something some where and those who have typed about that beat subject too often can just say out of it.

[David Weaver]

David,
Yup . . 54 too hard to file with western files, especially most all of the curent shlock, and I never bend my saws like the showman so I think I am safe here.
That was sure a nice saw you shared with us. Gives us a bench mark for everything else.

All you have to do is cough up a grand and get on the waiting list and you, too can have one I wish I was a more competent user of it, I can't convey the difference between it cutting 7/4 material and every run of the mill long kataba or ryoba that I've had. It was like riding 120 psi on cobblestones and having someone point you to a turn off on a freshly paved road with no expansion gaps on it.

[David Weaver]

my chip breaker rants and ultimately taking a head shot for my mistake is a good example..

Well, there's a lot more opinion there, of course. Some of us are partisans in that debate!

(I didn't, by the way, file stanley's saw at all. I figured it would be inappropriate to do something like that - I think I could've filed it with my vintage files. Stanley said to me when I complained that I might not like to test an expensive saw that I could break, that I would be quite sure as soon as I got a hold of it that it's not a saw that would be easily broken, and he was right).

[Winton Applegate]

partisans

But patriots when it comes to Neandering.

not a saw that would be easily broken, and he was right

Poetry in steel.

Problem is if I coughed up a thou and got it then I would want to use only that saw for every thing and would start posting about how one can cut dovetails with it and the stuff would hit the fan all over again.

. . .. . .
. . . .
. . . sayyyyy . . . that would be fun . . . .

[David Weaver]

I thought when I got it "this would be a good saw for stuff thicker than 4/4, but I might like to have one in 6 or 7 tooth for that..." (as in buy two).

(there was only one left when I tried Stans - it was the matching plate to stans from a pair. I think he said the maker makes a few dozen saws a year and that's it, so it's not like you can say "can you put another one with X# of teeth in the mail monday". I ALMOST bought that second saw, but I wavered a little bit and someone else did - which ultimately is good for my marriage)

[Rob Streeper]

David,

The Ames testers are very simple instruments to use. If you're interested go here http://www.amesportablehardnessteste...-instructions/ and watch the video.
True, it is not a bench style or other high precision tester but, like I said above, these are saw blades - hardly worth getting your blood pressure up. Plus or minus a half point isn't critical here.
I find it very disturbing that so many responses have included personal jabs directed at me. In my world, data is data and opinions are not data. Experience is not data either. If anybody has that data let's compare notes and be objective in the interpretations.
As I keep saying, nobody else has presented any data of any kind.

Thanks,
Rob

[george wilson]

Steve,I find it absolutely stunning that you seem to want an anything goes approach to posting "facts" here. Do you think anyone should post any old "facts" here and not be questioned about its validity? I hope our reporting press does not do things that way,or we'll never know what is really going on.

I just think getting facts straight is important. And I have given them several times in this thread,yet am still accused of just voicing my opinion. I know the hardness of every saw and chisel I own because I tested all of them with a reliable and correct RC range tester. Now,THAT was a "Crap load" of research that I did for my own education.

Rob,no personal jabs have been directed at you. And,the range of hardness for good old saws-40 to 45 RC,and new boutique saws @ 52RC compared to a figure of yours- 61,is not 1/2 f a point.