Posts: 504
Threads: 55
Joined: Feb 2017
Too many interesting points in this thread to do them justice in a reply today. Grandfather duty during the day and an Adobe Lightroom class this evening. At 67, I finally realized I don't have several years to muddle along learning digital photography. Time for some high power help!
I have BESS tested some chisels and turning tools. I think we will need to devise some jigs to hold the tools more consistently to advance to the level in place with testing knives. These could be simple wooden devices designed to hold the tool plumb and supported for more repeatable tests.
Most of my bench planes are 1909 vintage Stanley Bedrocks I purchased in 1972 from the original owner. No complaints and no coveting the new L-N or Veritas planes. The new premium tools are quite nice. I have a Veritas plow plane and several L-N bench chisels, all well designed and made. As such, I have no experience with the thicker blades.
No, I do not think Odate is overkilling with separate stones for each plane. I am sure for a man of his skill and artistry, separate stone, each carefully tuned for each plane, help in both efficiency and mental focus. I have separate Tormeks for each plane. (Just kidding, although I do have three Tormeks. That's a different story.)
Must dash.
Ken
Posts: 82
Threads: 1
Joined: Aug 2017
Grepper, thanks for the feedback, I'm sure once I have some experience testing I'll feel more confident. One reason I had some doubts was due to my initial testing of the PT50 - on the day I got it I tested several blades, including a newly opened razor blade, which measured 30. That seemed a bit low, so I put some test weights on the PT, and it measured them all correctly, so the machine is fine. I'm a software guy, so I always suspect user error (including my own) when things don't work as expected, so the doubt lingers...
Glad to know what your target is for knives, I was wondering what I should shoot for, and that will do fine for a goal. (Though I'm with Ken on this one, when freehanding I spend most of my time either off the edge or dubbing it.)
For woodworking tools, I've found that the higher the polish (which I'm assuming will mean the lower the BESS score), the longer the edge lasts. Not sure if this is due to the steel, the nature of cutting wood, or just my imagination, but once an edge is dull (or if it starts dull), it seems to dull at an accelerating rate. IOW, I think there's some value in very low numbers for planes and chisels, and since they're so easy to sharpen, no reason not to go that distance. But, since you brought up the trade-off, I'll keep an eye on it to see if my opinion changes.
Ken,
Happy grandfathering (have two of grandsons of my own)!
I like your idea of a testing jig, though I'm not sure how necessary it would be for someone experienced. When testing the inserts, I just put them in forceps or a hand vise, and pivoted them into the thread.
Got a laugh out of your "separate Tormeks for each plane." I have only one - use it mostly for grinding, not sharpening. That, too, is probably a whole 'nother discussion. FWIW, the thick blades on the LV or L-N planes make it easy to freehand sharpen once hollow-ground, so even I can get good results.
Steve
Posts: 945
Threads: 74
Joined: Mar 2017
Reputation:
0
08-09-2017, 02:47 PM
(This post was last modified: 08-09-2017, 02:54 PM by grepper.)
Was your blade a Feather brand? They are known to be sharper than other DE blades and numbers in the 30’s is not unexpected. Remember that your PT50 has a resolution of 5gf.
Visit here, scroll down to Click to See Data Summary – Sharpness and open it:
https://www.refinedshave.com/razor-blade...s-testing/
If you are at all aware of what you are doing when testing with the PT50, you will do fine. Really! Don't overthink it. It's just not that tricky to get good, consistent readings.
Posts: 82
Threads: 1
Joined: Aug 2017
Wow, I'm impressed! I had no idea what brand it was, but yes, it was a Feather. Amazed that you guessed that (though I can now see why).
Thanks for the link, interesting info. I rarely buy razor blades, but this is interesting info.
Overthinking is in my blood, but thanks to your input on the Feather blades, I'll relax a bit and just do it, and get some experience.
Posts: 945
Threads: 74
Joined: Mar 2017
Reputation:
0
08-09-2017, 10:34 PM
(This post was last modified: 08-09-2017, 10:45 PM by grepper.)
I have a programming / IT background too, so I know where you come from as far as over thinking goes. How does velocity impact the testing? What about media tension, temperature, etc.?
What it comes down to is that the PT50’s are amazing, easy to use instruments. Just slowly push the blade against the media until it breaks. It’s really as easy as that. Unless you are talking about super low readings, 50 or less, and worried about single gram increments, I’m sure what you are doing is just fine. Trust your readings.
And really, we’re talking about woodworking tools and knives. 5, 10, or even 20 grams one way or the other is not really all that significant. Readings of 150 gf or less is very sharp. I doubt that for all practical purposes that you could tell the difference between a 150 edge and a 170 edge when you are using the tool. 20 grams is the wight of 4 U.S. nickels (5 cent piece). Consider adding that amount of weight to the end of a chisel. Could you tell the difference when pushing it through some wood?
I believe that with woodworking tools a smooth, polished edge is what you want. Knives are a whole different animal with the choice of varying degrees of a toothy edge, how to get it and not ruin it when deburring. That is much more difficult to really understand and achieve.
Personally I always use the test media fixture rather than the clips. That way I don't have to worry about conversion factors or detensioning the clip, etc. The fixture works great.
Considering that you sharpened to a 105 gf reading, you are doing great as far as sharp goes! Soon you will trust the results of your PT50 too. So, yes. You can relax.  You are doing it right and everything is fine. It’s funny; after a while you just do a test and don’t really even think about it much. It’s really that easy, and produces reliable results every time.
Posts: 82
Threads: 1
Joined: Aug 2017
Thanks for all of the encouragement, you guys have been great!
I agree that I can't detect a difference of 20 (or more) grams when using a tool (with the possible exception of carving tools - and it's carving tools that are behind much of my motivation to better learn to sharpen), but now that I can measure the difference, it suddenly matters to me (I'm compulsively compulsive). Since I occasionally sharpen knives, and often do it freehand, I'm trying to figure them out as somewhat of a stepping-stone to carving tools (though knives may actually be more difficult - I frankly don't know, other than they're difficult for me). But yeah, chisels and planes are easy to sharpen, and not that critical of an edge; I'm sure under 200 is usually fine for most tasks.
BTW, I don't like the clips much, but with carving gouges and other curved blades, the fixture doesn't work (can't fit the blade in the slot), which is the only reason (and time) I'm using them.
Anyhow, I'll take the advice both you and Ken have given me, gain some experience, and keep on learning. I really do love the PT50, the feedback is life-changing for the sharpening process. (I have the PT50A, btw, so can be extremely anal about overthinking.)
Oh, and as to " How does velocity impact the testing? What about media tension, temperature, etc.?" - All great questions! <g> Add to that slant, angle, side-motion, and so on - now we're talking!
Posts: 500
Threads: 38
Joined: Mar 2017
Hello Gents - Noticed that there was some discussion here about measuring razor blades. If the interest is still there I would like to let you know that we have a customer who has devoted almost an entire blog to measuring both initial edge sharpness as well as edge retention for a large number of different brands of razor blades.
He's built a special test jig in order to reduce the "human factor" in the testing. We think that we have gotten pretty good at holding razor blades between our fingers and conducting tests but it does take a little practice and a steady hand.
He employs a PT50A for these tests and uses, I believe in the majority, disposable test clips. Here's the web site:
http://www.refinedshave.com
Posts: 504
Threads: 55
Joined: Feb 2017
Mike, An interesting site; thanks for the link. My interest is purely academic; I have not shaved since 1992. Before that, beards came and went beginning in 1967. There are more experienced shavers on the exchange.
Ken
Posts: 82
Threads: 1
Joined: Aug 2017
Ken,
Just wanted to thank you for the tip on Leonard Lee's sharpening video. I received the DVD yesterday, and have watched most of it - it's very good, and I love the old school approach. He demonstrated an approach to sharpening carving tools which I had seen before but had forgotten. I tried it today, and was very pleased with the result, so not just entertaining but quite useful.
Steve
Posts: 504
Threads: 55
Joined: Feb 2017
Steve,
I am pleased you are enjoying Leonard Lee's DVD. I have always regarded Leonard Lee highly, and regret never having met him. I find his book and DVD refreshingly straightforward, practical, and honest. I hope his dry humor amuses you as much as it does me.
Keep learning!
Ken
|
