Thread: HNT Gordon video - bevel angles

Originally Posted by planemaker

(youtube video) by DW; talking about micro chipping on A2 irons.

https://www.youtube.com/watch?v=iorPTbHZOVE

That guy doesn't know anything!! It's not scientifically tested!!

Originally Posted by rob streeper

I posted in response to the comment DW made dismissing 'the single variable crowd' and I think that, unfortunately, it has a lot do do with woodworking. In particular the trolling behavior that is far too common on woodworking websites such as this.

Last time we went down this road, you were hardness testing saws. You had a saw or two that wasn't made from 1095, you used it to call into question all sawmakers by refusing to identify it and then you claimed that you had reliable results showing vintage fileable saws to be 60-70 hardness in various places on the rockwell c scale. At the same time, you dismissed people who had 100 times as much experience and who had hardness tested the same things you were testing but on a versitron.

I've seen your scientific method, you are performing the role of assistant technician and asserting yourself as lead scientist.

There's something missing here, and that's credibility and the knowledge of when to throw data out, or even to define what problem you're going to solve.

It'd invite you as I have prior, if you want to make assertions about microbevels and full bevels, test them. It's not hard. If you get results that make no sense, expect people to question whether you know enough to make assertions. Be prepared for people with experience to question if you even know useful result you're trying to find.

You notice I make no question of Steve Elliot's results. And at the same time, I cast aspersions at Brent Beach's assertions of certain things, like his conclusion that stropping always degrades an edge (the real issue is that Brent Beach doesn't really understand what stropping is, or he doesn't have proper materials to do it. Nobody shaves without stropping, and there's no better test of sharpness that I'm aware of). There are certain things very useful about Beach's research, but there are plenty of assertions that are absurd that suggest lack of depth.

Originally Posted by planemaker

(youtube video) by DW; talking about micro chipping on A2 irons.

https://www.youtube.com/watch?v=iorPTbHZOVE

That was, by the way, in response to a question that Brian Holcombe asked. I probably elaborated on it earlier, but his issue was that he was sharpening around 30 degrees and trying to finish plane, and was constantly taking his plane apart to hone out nicks that leave tiny rows of lines. I've been in the same position, using charlesworth's sharpening method when I started, the irons lasted well and left a clean finish. When I went to freehand, i started around 30 degrees and they did not. they lasted long enough, but tiny lines showed up very early in the sharpening cycle, and I went back to the guide and sharpened at charlesworth's recommendation of 35, and they disappeared.

That may not be interesting to someone who isn't finish planing, but in Brian's case it's an instant problem solver and it doesn't require buying anything else when he had quite a fine plane to work with ( a lie nielsen bronze 4 ). That's a good conclusion, it was worth making a video to suggest to people who may not see Steve Elliot's excellent site.

Rob is just stating that the scientific method is extremely important when conducting experiments. At its most basic level the scientific states 'make every thing capable of being replicated exactly by others' and 'ensure that the variable being manipulated can be measured in a reliable and valid manner'. For example, if examining the wear on blades, ensure that the bevel angle and the conditions of use are the same for all. This is very basic stuff.

Dave is saying that not all experiments reflect real life situations. I see this in my day job, where I read a lot of psych research papers which appear undertaken just so people can say they have completed research. The information has little transfer to real life situations. In woodworking some "ideals", such as the perfect clearance angle or one perfect bevel angle for all blades, are unrealistic.

Regards from Perth

Derek

Sort of. I fully understand the scientific method and its significance. If this were a discussion other than woodworking with a simple scenario and two people evenly experienced, I always end up being the person who says "if that effect exists, you can prove it". I was an applied mathematics major with a concentration in probability and statistics.

I am wary, though, of people testing things that fit in a scenario that they're not generally participating in. A good experiment requires definition, context, a credible gatekeeper and interpretation, and I'd expect the following things to be covered:

* Do we have a problem that we can define, if so what is it?
* Can the problem be tested relevantly (that shouldn't be that difficult here)
* Once the problem is tested, do we have reliable results
* Do the results draw a definitive conclusion
* Is the conclusion useful? If it's not useful in regard to the original problem, is it useful for something else?

Generally, people applying scientific method where the result is credible and reliable are people who are experts in what is being tested. They have a better chance of defining a relevant problem, coming to a useful conclusion, and stopping and thinking when unreasonable results are observed and diagnosing what is causing the problem. In the case of the saw debacle, Rob floated out a soap-opera type scenario supposing saw sellers were ripping customers off and not giving them what they paid for, but the real problem was comparing saws of different alloys and refusing to name the saw with the soft plate (we could probably guess that, we know who uses 1095 and who doesn't). That was subsequently backed up with saws that were supposedly 60s hardness, which is bad observations (they wouldn't retain their spring at that).

If an expert is testing something like that, nothing is hidden to begin with, and we'd have never seen claims of things like 68 hardness in a saw plate.

I appreciate the scientific method just fine, I just appreciate if an expert in the subject discussed is overseeing it. Anything else is potentially tabloid quality.

Despite all of your bluster David I note that nobody, not even you, has offered any data to refute my findings in the interim. As to floating scenarios, no I didn't, I reported what I found. I wasn't pleased to learn that I'd spent quite a bit of money on a saw that was seriously flawed but given the other things I've been told privately I can say I'm not surprised.
Nonetheless, this is seriously off topic. If you want to criticize my saw plate hardness measurements there is a thread for that here: Hardening of sawplates

If you suggest that you have a saw that can be filed that's 60s hardness, discussing data with you doesn't really amount to much.

Then again, to someone who is actually sharpening and using a saw, I doubt they'd care if one plate was 47 and the next one 51.

I'll sit back and continue to wait for the carpenters saws that are better than Disston's and the reports of unusable modern boutique maker backsaws (if someone buys one of 1070 steel without knowing the spec, so bet it. Anyone else with a little bit of experience will spot a soft saw immediately upon sharpening).

Originally Posted by rob streeper

I posted in response to the comment DW made dismissing 'the single variable crowd' and I think that, unfortunately, it has a lot do do with woodworking. In particular the trolling behavior that is far too common on woodworking websites such as this.

As to your criticism of the Wikipedia articles I agree that they could be better but they are nonetheless correct and very important is their easy accessibility. If you're interested in a truly excellent discussion that is quite accessible to the non-specialist have a look atThe Discoverers by Daniel Boorstin. I strongly recommend it and it's old enough now that copies can be had very inexpensively in used book shops. Here's a link to a review of the book: From Experience to Experiment. In the book Boorstin emphasizes the importance of standardized measurements and how the dissemination of those standards was critical in laying the foundation of the modern technological world.

Thank you but I don't need educating, its a subject I know something about already and disagree with you about the correctness of the Wikipedia articles. This is not the place for that discussion.

Originally Posted by coffeefro

Thank you but I don't need educating, its a subject I know something about already and disagree with you about the correctness of the Wikipedia articles. This is not the place for that discussion.

Sorry if I offended you but my Wikipedia quotes were chosen for the reasons I described. My disagreement was with DW not you. If you have better web resources discussing the scientific revolution and scientific method to refer us to please post them.

Originally Posted by planemaker

Re David Charlesworth's recommendation for a 35 degree bevel angle. (A2 IRONS)



The Ruler Trick - Page 2 of 2 - Popular Woodworking Magazine

Why would David Charlesworth promote a non traditional bevel angle of 35 degrees.

*A2 Irons suit a bevel angle of 35 degrees.
*Lie Nielson only sells A2 Plane Irons.
*Lie Nielsen stock DVDs by David Charlesworth.
https://www.lie-nielsen.com/nodes/4226/videos/2?uri=

Wait a minute, I thought the magic-angle was 34^o, or was it 33^o, or was it 28^o?

Rob - I thought you'd know that? The magic angle depends on the magnetic alignment of the steel particles in the blade, which in turn depends on the direction the blade was facing (relative to magnetic north) when it was manufactured.

All this talk of blade angles has got me seriously considering buying the new Tormek T-8 sharpening beastie which I saw in Carbatec the other day. Interestingly, any remaining (slightly cheaper) stocks of the earlier T-7 seem to be flying off the shelves while you can still buy 'em. Carbatec Sydney sold their last T-7 already.....I think it was an unboxed ex-demo model, but someone snapped it up. The new T-8 adds about $200 to the T-7 price......but it's soooooo shiny . Tricky getting it home and into my shed unnoticed - the old "It followed me home, honest!" line is wearing a bit thin.

Originally Posted by Mr Brush

Rob - I thought you'd know that? The magic angle depends on the magnetic alignment of the steel particles in the blade, which in turn depends on the direction the blade was facing (relative to magnetic north) when it was manufactured.

All this talk of blade angles has got me seriously considering buying the new Tormek T-8 sharpening beastie which I saw in Carbatec the other day. Interestingly, any remaining (slightly cheaper) stocks of the earlier T-7 seem to be flying off the shelves while you can still buy 'em. Carbatec Sydney sold their last T-7 already.....I think it was an unboxed ex-demo model, but someone snapped it up. The new T-8 adds about $200 to the T-7 price......but it's soooooo shiny . Tricky getting it home and into my shed unnoticed - the old "It followed me home, honest!" line is wearing a bit thin.

Don't forget to get the expensive water treatment, a couple of hundred dollars worth of jigs, a big pan to put the whole thing in, a couple of different stone graders (in case you get the black stone, silicon carbide on silicon carbide tends to just make very fine silicon carbide on both things), maybe a drain in the floor in case you drop it and a spare wheel in case you break your wheel getting it off of the arbor!

I think we can get this thing to $2000 US and really feel good about standing in front of it and waiting for it to do something that can be done quickly on a $40 bench grinder.

Of course, I had one - one of the old "supergrinds". It frustrated me enough that I gave it away.

Slightly off topic to clearance angles; the following are comments from Bill Tindall referencing the Kato Kawai study.

Post subject: Re: David C - the Text from the Second Cap Iron Paper Posted: Mon Aug 08, 2016 5:35 pm

Hi all. I am Bill Tindall and new here. Some years ago while searching for a copy of the now famous planing video I tracked down Professors Kato and Kawai. I have corresponded with Professor Kato and he generously sent me all his scientific papers on planing as well as a copy of the video that is now widely available. (wow, this print is small and I can barely read it. No telling what I might be typing, but here goes.....)

To deal with David's submission.....I have no idea where that "translation" came from. It is a "translation" of the abstract in the paper. The original paper has an English abstract provided by the authors so there was no need to translate it. This paper was prepared as a tutorial for Kawai's students. Basically it says that when the shaving folds up like an accordion the cap iron is too close. For us, that is the only useful information in this paper.

Mia, the translator of the audio on the planing video, and the paper on wear and cutting forces, is a professional translator and woodworker and member of our club.

Kato and Kawai's work was funded by and was in support of the development of planing machines- Super Surfacers. They were mainly interested in prolonging blade life. Hence, there is work reported on the effect of cap iron on blade wear and studies on various steel alloys and blade wear as well as wear resistant coatings on the blade. None of the work investigated tear-out.

Personally, I think there is too much fuss on cap iron setting. Set it as close as you can. If the shavings scrunch up it is too close. If you get tear-out diddle with the distance until it goes away. Considering the physics of how the cap iron effect works there are too many variables to suggest one cap iron setting as best or optimum. It is an empirical journey. Accept it.

The video is NOT a tutorial on setting the cap iron. Professor Kato prepared the video for an engineering conference here in the US to demonstrate the capability of his research planing machine and photography. Many of the setting in the video never appear as settings in the planing studies as reported in the papers describing their work. Do not interpret settings in this video as recommendations.

I believe Kato and Kawai had little to say about setting a cap iron because this practice was widely used and known in Japan. There was nothing to add for the Japanese audience. Professor Kato was surprised and somewhat bewildered by the western interest in this facet of the work stirred up by the rediscovery and publication of the video in western Forums.

David C - the Text from the Second Cap Iron Paper : Hand Tools - UKworkshop.co.uk