saw plates old VS new

[David Weaver]

David,

I don't want to get into another battle with you. In my testing I've reported more data points than any other source that anybody here or on the Woodwork Forums ever has before. The reason that I haven't contacted you about taking the samples is that I'm not sure what your intentions are and I don't at this time want to give you my address. This is because you have been so vociferous in you denunciations of my data and I think somewhat unfair to me. If you continue talking to me reasonably, and I don't mean that you must agree with me, I may take you up on your offer.
I acknowledged the limitations of testing under the handles and in fact I was the first to point it out to the community - don't I at least get a little credit for having done so? In addition, I started the conversation about saw plate hardness despite the fact that I knew that there would be differences in opinion. There is really very little data on saw plate hardness available. More work needs to be done.
I just had another thought. I have a Disston No. 4 backsaw that likely was made some time in the WWII era. Were the blades of the backsaws hammer tensioned? Does anybody know? If not I could do C and N scale testing on that saw and report it. What do you think? The only data I have seen on a backsaw is presented at the Disstonian Institute in the discussion of saw steel and that saw was made in the 1800's and was reported to be very brittle.

Cheers,
Rob

My intentions are simply to get you saw plates that you could strike in a relevant area (halfway up the plate? An inch above the tooth line?). I'd have no interest in any of this if striking under the handle gave you relevant or meaningful data, but it doesn't. You are fascinated with statistics for empirical data sets, and I assume that you use a software package in your work, and thus the familiarity. Your example about bricks is suitable here, You're effectively measuring the straps on a lifejacket to see if it floats. When I have asked you questions about following why the hardness under the handle doesn't create a meaningful dataset, you have responded with comments about the empirical statistics, which completely misses the point. I am formally educated in statistics, that's not where the problem with your results and your conclusion are (they are in the collection and conclusion drawn from the data, not in the use of the data after it's collected).

I literally only have interest in you getting meaningful numbers and not making misleading statements. We have at least two people who have measured saws with C testers in professional labs, and both get similar results and they are not similar to yours. Your brick comment comes in again when that is the result.

Disston backsaws are similar hardness to their large saws. I have filed many, and most are not defective like the one in the disstonian institute page. I have encountered only one like that (a jackson branded saw made by disston that isn't very hard but breaks when the teeth are set anyway). The saws of vintage age that I have found to be softer are very old english saws - like 200 years old (though that may not be universally true) - and some later low price examples (a barber and genn saw I have is soft, but not unusably so).

My offer still stands to provide you (or coordinate people providing to you) sawplates that you can strike to get relevant data. I gathered early on that you are resistant to getting meaningful data because it will change your conclusion, especially now that you are this invested in defending the information you provided (which aside from the strikes under the handles of vintage saws seems to be reasonable). But the offer stands. Your study will have no credibility in regard to that conclusion until you correct it.

(the part about it being possibly dangerous for me to have your mailing address is humorous)

[Rob Streeper]

My intentions are simply to get you saw plates that you could strike in a relevant area (halfway up the plate? An inch above the tooth line?). I'd have no interest in any of this if striking under the handle gave you relevant or meaningful data, but it doesn't. You are fascinated with statistics for empirical data sets, and I assume that you use a software package in your work, and thus the familiarity. Your example about bricks is suitable here, You're effectively measuring the straps on a lifejacket to see if it floats. When I have asked you questions about following why the hardness under the handle doesn't create a meaningful dataset, you have responded with comments about the empirical statistics, which completely misses the point. I am formally educated in statistics, that's not where the problem with your results and your conclusion are (they are in the collection and conclusion drawn from the data, not in the use of the data after it's collected).

I literally only have interest in you getting meaningful numbers and not making misleading statements. We have at least two people who have measured saws with C testers in professional labs, and both get similar results and they are not similar to yours. Your brick comment comes in again when that is the result.

Disston backsaws are similar hardness to their large saws. I have filed many, and most are not defective like the one in the disstonian institute page. I have encountered only one like that (a jackson branded saw made by disston that isn't very hard but breaks when the teeth are set anyway). The saws of vintage age that I have found to be softer are very old english saws - like 200 years old (though that may not be universally true) - and some later low price examples (a barber and genn saw I have is soft, but not unusably so).

My offer still stands to provide you (or coordinate people providing to you) sawplates that you can strike to get relevant data. I gathered early on that you are resistant to getting meaningful data because it will change your conclusion, especially now that you are this invested in defending the information you provided (which aside from the strikes under the handles of vintage saws seems to be reasonable). But the offer stands. Your study will have no credibility in regard to that conclusion until you correct it.

(the part about it being possibly dangerous for me to have your mailing address is humorous)

Let me reassure myself for a while and I'll reconsider your offer.

To a degree you're right when you point out my reliance on empiricism. I am employing the tools and techniques I have to try to understand an issue that appears to be much discussed but which has really not been subjected to much in the way of systematic inquiry. I'll keep posting my results, warts and all, because I think it's necessary to supplement the scant information available on this subject.

[David Weaver]

Let me reassure myself for a while and I'll reconsider your offer.

To a degree you're right when you point out my reliance on empiricism. I am employing the tools and techniques I have to try to understand an issue that appears to be much discussed but which has really not been subjected to much in the way of systematic inquiry. I'll keep posting my results, warts and all, because I think it's necessary to supplement the scant information available on this subject.

The fact that there's little data makes it even more important that it's accurate.

if the old saws are indeed harder (in a usefully measured area), then that is a fairly big deal. If they are not and the data suggests they are because it's from irrelevant areas on saws, or because the sample size is too small, that's a very large problem.

We have two data sets other than yours. George provides a range from his strikes. It's still data even if he didn't supply it in a spreadsheet. The data also on the old tools list is in line with what george provided (and they are not related items, so there is independence in measurement). That poses a real problem.

I don't think you should stop providing data, I just think it needs to be corrected so that what is collected in line with the conclusions that are drawn from it. If your means are limited, or striking your own saws at the teeth is a real problem, let me know once you're comfortable, and I'll buy one of the "opportunity lots" on ebay, label the plates and take off their handles (I could probably use the saw nuts, anyway) and send the plates in a flattened mailing tube. It will be much easier to send a half dozen or so without the handles, anyway. I believe I have two from my own stock that could be used for this, though I may have thrown the plates away in the past. I'll have to check - even if i don't, it is easy to come by more top line saws that have problems that make them duds for a user, but perfect candidates for your data collection.

[Rob Streeper]

The fact that there's little data makes it even more important that it's accurate.

if the old saws are indeed harder (in a usefully measured area), then that is a fairly big deal. If they are not and the data suggests they are because it's from irrelevant areas on saws, or because the sample size is too small, that's a very large problem.

We have two data sets other than yours. George provides a range from his strikes. It's still data even if he didn't supply it in a spreadsheet. The data also on the old tools list is in line with what george provided (and they are not related items, so there is independence in measurement). That poses a real problem.

I don't think you should stop providing data, I just think it needs to be corrected so that what is collected in line with the conclusions that are drawn from it. If your means are limited, or striking your own saws at the teeth is a real problem, let me know once you're comfortable, and I'll buy one of the "opportunity lots" on ebay, label the plates and take off their handles (I could probably use the saw nuts, anyway) and send the plates in a flattened mailing tube. It will be much easier to send a half dozen or so without the handles, anyway. I believe I have two from my own stock that could be used for this, though I may have thrown the plates away in the past. I'll have to check - even if i don't, it is easy to come by more top line saws that have problems that make them duds for a user, but perfect candidates for your data collection.

David,

Sounds fine to me. I've thought of a way to receive them. I don't know you yet and I feel the need to be careful.

I had a laser pointer incident recently. The responding police officer told the person who pointed the laser that, if the laser had been pointed at him, the holder of the laser pointer would have been shot. Never hurts to be careful you know?

As to your proposal, here is a picture of the surface of a hardness standard. I realize that finding a cheap old Disston with this kind of finish is going to be difficult if not impossible but we want something as close to this as is reasonable. I can of course grind and lap the surface of a blade but that will result in the readings being lower than the true hardness of the blade.

test block.jpg

If and when you find something send me a PM and post the pictures here so all can comment on the design of the testing strategy. Once we have a consensus I'll PM you an address. Then I'll do the testing as agreed and report the results here. In the meantime I'll tweak up my B/C tester to increase the linearity and work out some of the intercept offset I have now. Perhaps you could get somebody else from the forum to do some parallel testing on the same plates and then send them to me, or send them to me first and I'll send them to the next tester?