Replies

1. 
   DCarr10760 | Sep 13, 2006 05:24pm | #1

   Pare some pine endgrain, if it looks waxy and the growth rings are clearly visible then your blade was as sharp as it could be, however, you just dulled it. 

   But you'll sleep better knowing that for one brief shining moment you had the sharpest blade in the world!

   That and six bucks will get you a Mocha java cappafrappachino at any Starbucks in the world.

   David C

2. 
   AdamCherubini | Sep 13, 2006 07:08pm | #2

   "As sharp as can be" is the operative term here.  Don't know how to check that.  If we could reword the question to "sharp enough", I'd like to offer my technique:

   I have two tests- both slicing copy paper.  The first test is for hatchets and tools for rough use.  I draw the edge across the paper's edge noting the sound. I'm looking for rough spots in the edge. My theory is that nicks cause the edge to prematurely break down.  I check the paper to see if it is cutting cleanly or tearing.  I'm looking for a clean cut and an evenly sharpened edge. I stop there for hatchets or my adz. 

   Once that test is met, I try pushing the tool edge on, straight into the paper with no drawing motion.  This test I reserve for chisels and plane irons.  When a tool passes this test, it is sharp enough for me.

   I like to strop edges and I visually inspect edges from the stone or sand paper to ensure it is uniformly polished before and after I strop.  Again- my feeling is that deep scratches, especially those parallel to the edge and any tiny nicks or imperfections cause the edge to crumble prematurely.  I'm pretty sure this is "good science".  But that has more to do with edge retention than overall sharpness.  I also have, but don't love a veritas edge bevel gauge (the holes are too big).  I find this is a helpful predictor of how an edge may behave.  Its not unusual for me to have a tool whose bevel varies significantly. I've even experimented with this on purpose.  Like many of my "experiments"* the results were inconclusive.

   Adam

   * Last year I made a saw thinking the 18th c design would be superior to modern saws.  Made sense on paper anyway.  I like my new saw and use it almost exclusively, but I really don't see any significant difference between it and a modern saw insofar as its design goes. I think the way a saw is sharpened, even down to minute differences of rake angle, can be easily felt.  The angle of the handle, shape of the blade seem to have much less effect.

3. 
   joinerswork | Sep 13, 2006 08:22pm | #3

   jack,

   I bet your wife dislikes that little bald spot on the back of your arm!

   Under a good light, look at the tool edge-on.  If the edge or any portion of it, can be seen (it will be a white line) it isn't sharp.  A sharp edge tapers down to nothing, so, you can't see it.  I feel the edge by stroking a finger  alternately from the bevel off the edge and from the back off the edge, to make sure there is no "wire edge" left from stoning.  A little stropping will take care if this if it is there. 

   Others have recommended drawing the edge (lightly!!) across the back of one's fingernail.  A dull edge will skate while a sharp one will drag.  But that gives me the same uncomfortable sensation as fingernails on a blackboard.

   Regards,

   Ray Pine

4. 
   JohnWW | Sep 13, 2006 11:10pm | #4

   "Sharp as it can be" is way sharper than it needs to be for real world woodworking.  If the blade is sharp enough to cut cleanly without struggling to push the tool, the blade is sharp enough for the job at hand. 

   Too many people make a fetish out of creating super sharp blades that don't cut any better than an adequately sharp blade.  In addition, super sharp blades have very fragile edges that will immediately break down to the level of an adequately sharp blade after the first pass down the board, so nothing is gained for the extra effort made.

   John White, Shop Manager, Fine Woodworking Magazine

1. 
   TaunTonMacoute | Sep 13, 2006 11:26pm | #5

   Bravo. 

   Well said.

    

   Edited 9/13/2006 4:26 pm ET by TaunTonMacoute

2. 
   DCarr10760 | Sep 13, 2006 11:31pm | #6

   Right you are John.

   I actually never check for sharpness.  When honing I check for a burr or wire edge, then I strop and I KNOW it's sharp enough.

   I've tried Scary-sharp and Japanese Water stones and diamond and ceramic and green paste and red paste and more often than not I walk over to the old Arkansas stone and ol' leather strop and have at it.

   My tools are always sharp enough!

   David Carroll

1. 
   TaunTonMacoute | Sep 13, 2006 11:58pm | #7

   Another good point... once you've produced an edge that works all you do is repeat the process the next time with the self-assurance that it will work again.

    

1. 
   JohnWW | Sep 14, 2006 01:04am | #8

   Thank you all, I really thought I was going to get a lot of flack for my comment.

   However for what it is worth, since the question was sincere, here are three things I do to check that I've got the full width of the blade sharpened equally all the way across:

   1.  When I sharpen with a grinding wheel I grind until I've got a wire edge across the whole blade, I think someone already mentioned this, then I go to a flat abrasive, usually fine and very fine diamond stones, to finish up, usually with no further checking.

   2.  For long blades, like a kitchen knife that I'm sharpening free hand with a small stone, I use the technique already described of sighting down the length of the blade under a good light to see when the edge stops reflecting because it has come to a point.

   3.  I often use my thumb with just light pressure, dragging it crosswise to the edge, not enough to cut the skin but enough to feel the difference between the way a sharp and a dull edge drags on my skin.  I often do this to check the condition of a blade that is in use and is getting dull.  Usually you can feel the most worn areas as being different from the sharper sections of the blade.  This works especially well with jointer and planer blades where the outer ends will still be factory sharp but the more used central area will feel duller to the touch.

   John W.

3. 
   AdamCherubini | Sep 14, 2006 03:42am | #9

   Hi John,I really appreciate your sentiments and feel the same way. I think too much is made of sharpening BUT...I'm not sure I agree with everything you've written:"Too many people make a fetish out of creating super sharp blades that don't cut any better than an adequately sharp blade."I'm not sure this is a fact. I think sharper blades DO cut better and some techniques depend upon them. While the point is highly debatable, I've found the difference between a good tool and a great tool is often the condition of its blade. So one might find a cheap bailey plane with a really sharp iron may perform as well as an expensive plane with less sharp blade (that's just an example)."In addition, super sharp blades have very fragile edges that will immediately break down to the level of an adequately sharp blade after the first pass down the board, so nothing is gained for the extra effort made."I'm not sure this is true, although it is more or less my experience. Whenever these discussions come up, guys start BSing about metallurgy. I'm not a metallurgist but I have friends who are some of the best in the USA- They say tiny scratches accelerate wear. I don't understand it too well but generally they seem to say higher polished edges are stronger and will last longer. Also, a broken down highly polished edge is not the same as a less polished edge broken or not. Then there's this thing they call edge "morphology" (which I don't understand). Basically they tell me its advantageous to hone back and forth instead of side to side. I don't mean to quibble. I agree with what you say. And there's more to this subject than anyone of us cares to know. I don't think woodworkers need super sharp blades, but I think they do perform better and probably hold up better as well. Anyway, that's my two cents.My last article of this year is about sharpening techniques and equipment of 18th c cabinetmakers. Not to give the ending away, but I spent a lot of time working with tools that really weren't that sharp. I gotta say, that really sucked. Woodworking is more fun with sharp tools. I know as I've gotten better with my hands, I've been able to work with duller tools. So some of you may be able to "get away" with tools you would have had trouble with as beginners.Adam

   Edited 9/13/2006 8:54 pm ET by AdamCherubini

5. 
   rarebear | Sep 14, 2006 06:24am | #10

   I worked for a company called Atlanta Sharp Tech before I had to retire due to medical reasons and I worked as a machinist for 30+ years

   We made saw blades and best way you can check a edge is with a 6x-10x eye loup should do you fine, unless you have a microscope :)

6. 
   hammer1 | Sep 14, 2006 07:54am | #11

   In the days of straight razors, you place the edge on your fingernail and move it in a scraping motion. A dull blade will scrape, a sharp one won't move.

   Beat it to fit / Paint it to match

7. 
   WillGeorge | Sep 15, 2006 05:00am | #12

   You could try and cut your finger?

   Just funning you 'I think?' The finger nail thing works for me.

   
   

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   Edited 9/14/2006 10:02 pm by WillGeorge

8. 
   highfigh | Sep 15, 2006 07:49pm | #13

   If you have good eyesight, look along the edge in good light and tilt it back and forth to see if there's a line, as was mentioned before. If you see little or none, try it out. I have been planing more maple than anything else lately so I use a scrap, planing the face, edge and end. If it does a good job, I give it a couple of additional passes and get to work.

   As John and others have said, trying to reach the Nirvana of sharpness is a waste of time. The edge can only be sharpened to the radius of the largest particle or the coarsness of the meduim, whether it's sandpaper, waterstone, oil stone or grit on a strop. The Leonard Lee book explains sharpening very well and shows microscopic photos.

   Trying to get it impossibly sharp will drive you nuts. Get to work!
   "I cut this piece four times and it's still too short."

   
   

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   Edited 9/15/2006 12:50 pm by highfigh