Replies

1. 
   UrbaneLegend | Jan 06, 2008 03:24pm | #1

   Let me jump in before the sharpening wonks, professional blogists, and readers of tool catalogs smell blood in the water: any of those will do.  Your point of reference ought to be the 18th century when everything was done by hand and apparently quite well.  Somehow they got along without machinist's grade flat surfaces with which to polish up chisels.  And don't bite on the notion that they were successful in spite of their tools.  That's baloney of the highest order.

   Over the relevant area, which is quite small, a flattened piece of hard Maple would do just fine by the way.  Don't let the sharpening 'experts' (boy, that's what I want to be when I grow up - how 'bout you?) blow too much smoke up your butt.  You'll never get anything done if you do, and you'll look silly with smoke coming out of your derriere.

   
   

   ---

   Edited 1/6/2008 10:59 am ET by UrbaneLegend

1. 
   Woodman41 | Jan 07, 2008 05:16am | #5

   Well said! At some point the law of diminishing returns kicks in and an edge is about as sharp as anyone could possibly notice. If you are going to the electron microscope to inspect the edge, or better yet measuring the degree of scattering as light reflects off the cutting edge, well you might just be going a little overboard.I always chuckle when I read about the latest sharpening method or gizmo that puts a better than surgical edge on tooling. I use my Tormek and a leather strop and my tools are always sharp enough for the job at hand. Did you know that volcanic sand from a secret island in the South Pacific makes a wicked abrasive slurry, only surpassed by crushed bone fragments from the 4th rib of a non-believer?

2. 
   bones | Jan 06, 2008 05:39pm | #2

   Either of the two you cited will work fine.  I use the scary sharp method and I started with that. I had no experience shapening and thats one of the reasons I stayed away from hand tools i.e chisels & hand planes. I bought a piece of machined granite from woodcraft for 15 or 20 bucks (can't remember). It came in a wood box and I put it up on the bench when I need it. I use wet dry sandpaper & I bought David Charlesworths dvd on the subject of shapening (he's great on any subject). I got a water spay bottle from the dollar store, and I spritz the block with water and put a piece of paper down that I got from an autobody supply place (they have better grits of wet/dry), and it sticks and gives me the moisture to create the slurry. I generally use half sheets.  For the chisels I also bought the lee valley jig to hold the right angle and then a one degree bevel.  Works great for me.  The only advantage I could see to the glass is the weight. End the end, if you have easy access to either, they both will work fine. I don't see one better than the other per se in that one does a better job.  Have fun and good luck.

   Government's view of the economy could be summed up in a few short phrases:
   If it moves, tax it. If it keeps moving, regulate it.
   And if it stops moving, subsidize it.
   
3. 
   saschafer | Jan 06, 2008 06:28pm | #3

   I use a piece of 1/4" plate glass. It works fine. I attached some high-friction adhesive disks on the back side so that it doesn't slide around. You can get them from Lee Valley:

   http://www.leevalley.com/wood/page.aspx?c=2&p=32066&cat=1,42363,42348&ap=1

   -Steve

    

1. 
   KiddervilleAcres | Jan 07, 2008 08:59pm | #7

   Steve,

   I too use scary sharp and had the sane issue with the glass.  What I did was a variation on a benchhook to hold the glass.  Works great.

   Regards,Bob @ Kidderville Acres

    

   A Woodworkers mind should be the sharpest tool in the shop!

1. 
   charnwood123 | Jan 07, 2008 11:25pm | #8

   Thank you to everyone for your replies I agree totally it is a nonsense to take things to the nth degree but it is important to ask questions to test understanding

   33 years ago as an A level student here in the United Kingdom I can remember completing a light experiment where changes in the observed pattern of light was used as a measure of flatness

    Two good ideas came from your posts the modified bench hook and the spray bottle again many thanks

    

   Charnwood

1. 
   saschafer | Jan 07, 2008 11:50pm | #9

   "...I can remember completing a light experiment where changes in the observed pattern of light was used as a measure of flatness"

   That's still how they do it. The wavelength of light is the smallest "measuring stick" that we have readily available.

   -Steve

    

1. 
   UrbaneLegend | Jan 08, 2008 02:01am | #10

   "...I can remember completing a light experiment where changes in the observed pattern of light was used as a measure of flatness"

   That's still how they do it. The wavelength of light is the smallest "measuring stick" that we have readily available.

   Please God, don't let Derek Cohen read this.  :-)

   Edited 1/7/2008 6:02 pm ET by UrbaneLegend

2. 
   charnwood123 | Jan 08, 2008 05:01pm | #12

   I am 50 years young and I was educated in the United kingdom where I live. At the age of 16 to 18 I studied the following "A"(advanced) level subjects Physics ,Chemistry and Zoology

   In Physics were were extremely well taught by a former  Australian World War 11 RAF.radio operator and a former United Kingdom ministry of Defence Radar expert.WE were taught from first principles based on the recognized Theories ,laws and hypothesis that underpin how we understand how the world around us works

   Surprisingly this knowledge often helps when people try to explain  subjects  eg flatness

   regards charnwood

   Edited 1/8/2008 9:09 am by charnwood123

   Edited 1/8/2008 9:10 am by charnwood123

   Edited 1/8/2008 9:13 am by charnwood123

   Edited 1/8/2008 9:36 am by charnwood123

3. 
   BossCrunk | Jan 08, 2008 05:10pm | #13

   I'll chime in here and urge you to let your woodworking be more about art than science. The sharpening stuff is pretty easy if you let it. A plain piece of glass is plenty flat for your sandpaper set up. One of the thicker pieces sold by woodworking suppliers is a slight upgrade and nice to have.

4. 
   saschafer | Jan 08, 2008 05:49pm | #14

   "Please God, don't let Derek Cohen read this."

   Here are some optical flats that Derek can use. With one of these and a green laser pointer, he should be able to flatten a surface to better than ±50 nm. That would make the "hills" less than 500 atoms higher than the "valleys." If he needs to do better than that, we can set him up with a scanning tunneling microscope (±1 atom).

   -Steve ;-)

    

2. 
   JamesS | Jan 08, 2008 04:13am | #11

   I too use 1/4" plate glass. I tape all the different grits on BOTH sides & when using it I lay it on a pc. of router pad. It doesn't go anywhere.

   James

4. 
   TomHigby | Jan 06, 2008 10:50pm | #4

   This is really "straining at a gnat".  There's no place in wood-working where that degree of flatness is important.

5. 
   JeffHeath | Jan 07, 2008 08:23am | #6

   This oft asked question has an easy answer.  Anything that is hard and flat, that stays hard and flat with a fair amount of pressure applied, will work as a good substrate for sharpening. 

   ANYTHING!!!

   Get the tools sharpened, and get them to work, as quickly as possible.

   Jeff

6. 
   AdamCherubini | Jan 08, 2008 08:22pm | #15

   I have a whetstone from the Charnwood forest. It was among the best available to early English craftsmen. Cuts slow.

   My answer is similr to the others here. Any will work. To be fair though, you will not notice any difference up to a certain point. Beyind that point- where your media is basically stropping, there will be a noticeable difference. I don't hone that fine, so it doesn't matter to me. But if you chose to use the 10,0000 grit paper, you'll be able to notice the difference. So there's a caveat.

   I sharpen on 3 pieces of 1/2" corian. The finest stuff I put on there is 15 micron film I think. Something in that neighborhood. A fellow like David Charlesworth, working on figured stock or doing something amazing with wood might say- "that's not nearly sharp enough".

   So its all based on what your are actually doing, what your expectations are, etc

   Adam

1. 
   BossCrunk | Jan 08, 2008 10:07pm | #18

   I think it's Charnley Forest.

1. 
   AdamCherubini | Jan 08, 2008 10:24pm | #19

   "I think it's Charnley Forest."Isn't it the same? Bother. I can't keep English contractions and pronunciations straight. I thought its name was Charnwood and they called it Charnley.Adam

1. 
   charnwood123 | Jan 10, 2008 11:04pm | #20

   It is Charnwood Forest and is pronounced as written

   Within Charnwood forest there is a place called Bradgate Park the former home of Lady Jane Grey .She was Queen for 9 days in 1554, she was then imprisoned in the Tower of London accused of treason then beheaded

   As a sign of mourning and a mark of respect the inhabitants of Bradgate park, pollarded (cut off the top of) every Oak tree in the park

   Edited 1/10/2008 3:11 pm by charnwood123

   Edited 1/10/2008 3:13 pm by charnwood123

1. 
   BossCrunk | Jan 10, 2008 11:16pm | #21

   Charnley seems to be the most common usage:

   http://www.antiquetools.com/sharp/sharphistory.html

   http://en.wikipedia.org/wiki/Sharpening_stone

   http://books.google.com/books?id=fMZwUGf6wJoC&pg=PA122&lpg=PA122&dq=charnley+forest&source=web&ots=xLtPKe28-m&sig=JNrHatyYBC5matS585HeaGnI8bg

   (see page 122)

   http://zo-d.com/stuff/tool-history/a-brief-summary-of-the-different-types-of-japanese-waterstones.html

   http://www.motherearthnews.com/Homesteading-and-Self-Reliance/1983-03-01/The-Whetstone-Quarry.aspx

    

    

   Edited 1/10/2008 3:24 pm ET by BossCrunk

   Edited 1/10/2008 3:26 pm ET by BossCrunk

7. 
   Yitz | Jan 08, 2008 09:29pm | #16

   Howdy,

   I use a couple of cheap ($5-$8) polished synthetic (?) granite floor tiles bought from Home Depot.  They looked flat enough to me (by looking at the reflection of the flourescents in the glossy tile) and they seem to work fine.  I plan to buy some of that non-skid mat stuff (for rugs) next time I near the store.

   ANOTHER QUESTION FOR THE GROUP:

   When Scary Sharpening, how long is your stroke on the paper?  (BTW, I also use the Lee Valley sharpening jig)  I am thinking an inch or two works better (sounds like shikka-shikka-shikka) as opposed to the length of the 1/2 sheet (swoosh-swoosh).  Any thoughts?

    

   Yitz

1. 
   KiddervilleAcres | Jan 08, 2008 09:51pm | #17

   Whether you prefer shikka-shikka-shikka or swoosh-swoosh, I don't think it really matters all that much as long as the results are what you're looking for.

   As for holding your granite slab, why not make a simple bench-hook with sides that end up just below the top of the slabs?  Can be made from scraps - cheap!  It also helps to keep the mess somewhat contained and off the bench.

   Regards,Bob @ Kidderville Acres

    

   A Woodworkers mind should be the sharpest tool in the shop!

8. 
   Caesar29 | Jun 21, 2020 04:55am | #22

   What about flattening a smoothing plane´s base. the whole entire capitalist system may tweak if you find a solution for this.... Is it safe to say that a piece of MDF with a glued sandpaper is as good as wet sandpaper over marble for this purpose? is marble more flat than glass? or should I go buy a new Lie Nielsen tool and forget about it...

9. 
   chipsawdust | Jun 21, 2020 01:40pm | #23

   @Caesar29 That exact reason is why I went and bought a piece of granite from WoodCraft. I have a couple 1o0 year old planes and one of the two needed flattening (a foreplane to boot). The granite block was perfect, relatively cheap (I think under $40) and it worked really well. Also good for flattening water stones.

10. 
    lat_axe | Jun 21, 2020 01:55pm | #24

    I like glass 'cos its very flat of itself yet easy to cart about in the shed. A 3" thick slab of granite or cast iron .... not so portable. Also, gravity flattened the float glass whereas some granite slabs and those made of other materials are flattened by machining. How good is the flattening machine? Not as good as gravity on molten glass, I suspect.

    What I like to think about is how much the sheet of whatever is the substrate can flex when you're rubbing at the scary paper on it with your blade or even a big fat plane sole. Put a sheet of float glass just 1/4" thick on two battens with the majority of the sheet of glass unsupported and you can bend (sink) the unsupported part with not much pressure. A granite tile flexes a bit less but is also more prone to a snap, especially if it's conglomerate has "faults" between the lumps of this and that within such tiles.

    But in practice, just put the thing on a table saw or bench top that's pretty flat itself. No one uses two battens to support their granite tile, do they? :-)

    Float glass can be got out of skips (dumpsters) It doesn't warp in there, despite the rats and old burgers. Perhaps granite tiles can be so-got too; but they might be broke.

    Lataxe