Replies

1. 
   jackiechan | Sep 19, 2005 06:15am | #1

   Z',

   The Scary Sharp method does work, and can be a somewhat cleaner alternative to oil or water stones. 

   While reading your description, the first thing that came to mind is that the paper backing surface isn't flat, or is deflecting while you are trying to flatten the back of the chisel.  But since you tried the cast iron saw top and the router table top with similar results, a flat surface doesn't seem to be an issue.

   When flattening the back of a bench chisel, it is only necessary to dress the first inch to inch and a half starting measured from the cutting edge.  The key to creating a flat back is to apply even pressure across the width of the chisel, and maintaining even pressure as the tool is moved forward and backwards on the paper.  The pressure should be firm, but not to the point where it is hard to move the tool.  If your fingertips are turning white while applying pressure, you're pushing too hard.  On the wider chisels, attempt to place at least two fingertips side by side across the width of the blade at the top of the bevel (the non-sharp end!).  Stand with your shoulders over your hands, and allow your body to rock with the movement of the blade along the paper.  This will afford you a greater amount of control, and will serve to help maintain even pressure throughout the pass.

   It may just be that the back of your new chisels are just very roughly ground.  If you find yourself grinding away for hours and the backs are still not flat - return them, and tell the store that they are unusable do to poor machining.

   It can take a while to flatten the surface of chisels, plane blades, etc... but you'll only have to do it once.  Then it's just a matter of maintaining a sharp bezel (bevel - you'll see the same thing referred to in both ways).

   If you have any questions, please feel free to ask!

   Dan Kornfeld, Owner/President - Odyssey Wood Design, Inc.

2. 
   Yogi | Sep 19, 2005 06:30am | #2

   Zippy-  Who made your chisels?

3. 
   DCarr10760 | Sep 19, 2005 06:56am | #3

   Zippy,

   I use a modified scary sharp method, for heavy grinding I use 60 grit stikit on a 40-inch x 3/8-inch plate glass shelf.  From there I use 12 x 12 polished marble tiles and I have a bunch of them. I progress through 80, 100, 220, 320, 600, 800, 1000, 1500 and 2500 a full sheet of each on a tile.  It seems like a lot of steps, but after the initial grinding is done, a chisel only needs a dozen strokes on each grit to get to that "count your nose-hairs" mirror polish.  Then I strop on leather.

   I personally have never used a better system for sharpening.  It is space intensive, but I have a special bench set up for it, so I can hone a chisel secondary bevel in a few seconds.

   I don't bevel grind the blades on a wheel unless I nick them deeply, the 60 grit on the long glass is very fast.  (I am beginning to wear down the brass roller on my old LV honing guide though!)

   Maybe using a longer piece of 60 grit will help,  You might try a long peice of Stik-it on your tablesaw table or jointer bed as a test.  Put the paper close to the edge so the butt of the chisel isn't in the way.  Take long strokes with considerable but controlled pressure.  You want the abrasive to cut, but not so much pressure that you wear down the paper prematurely.  Oh, and when you are done, vacuum the sanding grit off of the fence rail and miter slot or you'll scratch things up a good bit- don't ask me why I know this.

   Incidently, I recently purchased a set of Crown bevel-edged skew paring chisels.  These chisels had been buffed at the factory with great enthusiasm, to the point where the edges of the flat side were radiused!  Even the cutting edge!  It took a half an hour to flatten past the rounded corners on the 60 grit.  Might be the case with yours too.

   Keep at it!

   David C

1. 
   dimitri | Sep 19, 2005 10:38pm | #5

   David,

   You mention that you strop on leather after going thru the grits! Can you explain exactly how you strop on leather?

   thanks,

   Dimitri

1. 
   DCarr10760 | Sep 19, 2005 11:07pm | #6

   Hi Dimitri,

   Well I started with a nice strop from Germany designed for razors, square in section covered on three sides with leather (the forth had a slate stone that I never used.  You rubbed different compounds into the leather.   I wore that one out and I cant find another.

   So now I use the back of an old weight training belt which, ahem, no longer fits... I wipe on mineral oil then work in Dico Jewelers Rouge (JR1).

   A couple strokes (pulled, not pushed) on the back and the bevel every now and again between honings and you're slick-sharp.  I leave a portion with no compound and strop on that for a final touch, not sure it does any good but I feel better!

   David C

4. 
   jazzdogg | Sep 19, 2005 07:18am | #4

   Hi Zippy,

   When I first read your post I thought 60-grit abrasive is far coarser than I would use unless the chisel had conspicuous mill marks or a damaged blade, requiring me to remove a lot of steel. It would be fairly easy to misshape a chisel with such a coarse grit.

   With new chisels, I typically start by removing the protective layer of lacquer,  and visually examining each tool with a precision engineer's square for squareness, a flat back, parallel sides, etc. I don't like to discover anomalies after I've begun sharpening; I prefer to know about them in advance, and address them strategically.

   Sharpening comprises two complimentary processes: Shaping, and polishing. First, make the geometry correct. Then, use successively finer abrasives to polish the two steel surfaces that form the cutting edge until you have achieved an intersection of zero width: a sharp edge.

   Sharpening has a lot in common with rubbing out a finish: that is, in both cases, I would prefer to err by using an abrasive that's too fine, instead of an abrasive that's too coarse; I can always back down to a coarser grit if I have to remove more steel to flatten efficiently, but if I start with too coarse a grit, I'll have to do more work to remove the coarse scratches.

   Next, I'll do what I call tentative honing of the back: I start by examining the steel using a high-quality light and a 10-power objective lens. Then, commencing with an abrasive that's slightly finer than I think is needed, I'll take enough strokes to enable me to clearly visualize the resulting scratch pattern with my objective lens; this helps me decide on a starting grit. The lens also helps me visualize the condition of the cutting edge far better than my myopic eyes can - even with bifocals.

   I'll typically flatten and polish the back before I begin sharpening the bevel/bezel. There's no hard-and-fast rule that says you can't alternate between back and bevel and you work your way up the grits. However, I find that it's generally easier to perfect your skills on the flat back of a chisel or plane iron, developing your muscle memory and skills of observations, before you try to shape and hone the bevel.

   Keep an eye on both the geometry and degree of polish at each stage of the sharpening process. Only when you have each surface honed with a consistent scratch pattern across the entire surface, should you move up to the next highest grit in the progression.

   The final step involves the removal of the wire edge that results from shaping and honing the back and bevel. I typically don't worry too much about this until I reach the 4000-8000 grit stage.

   If you are able to visualize the surfaces you are shaping and honing - at each stage of the sharpening process - you will be in a position to identify the process during which the wheels fall off of the wagon, so to speak.

   Please don't hesitate to reply if you have questions. Good luck,

   -Jazzdogg-

   "Don't ask yourself what the world needs. Ask yourself what makes you come alive, and go do that, because what the world needs is people who have come alive." Gil Bailie

5. 
   PJohn | Sep 24, 2005 01:50am | #7

   Hi, Zippy -

   Toughie. Agree with advice so far, but have a couple of ideas that may be helpful. Nothing described seems to indicate faulty technique, and you may indeed be faced with an "eternity" of scrubbing to get the initial flats established (I've pitched a few cheapies that were more easily trashed than fixed.) I've also spent over 2 hours with 60 grit on one "good" but wide chisel (1-1/2") before finally achieving flatness - same with plane soles - doesn't seem to me that you're doing anything obviously crazy. It only takes a few thousandths of discrepancy to engender several hours of misery. (That can also be in part the diff between a $15 chisel and one for $50. If the $15 job is good steel, etc., then you earn the value difference with honing time to get 'em into "right" condition.)

   Be patient - you only have to do it once. If you're doing fine work, then nicely shaped and conditioned chisels will make a difference you honestly can feel, and will certainly return better surfaces.

   You don't mention brand name - if they're not from a reputable manufacturer, it's quite likely that their machining is not up to snuff. Too much 60-grit "grinding", and you may introduce non-parallelism between front and back, though I'd suspect that condition from the outset if the chisels are poorly manufactured.

   I discovered that stickyback paper is suspect. Had ordered over $90 worth of varying grits from Klingspor (should be among the best), and discovered that most of the rolls had ropes of glue running down their backs - nothing horrible, but more than sufficient to make "flat" an impossibility. Returned the whole kit and kaboodle, and now use either water or WD-40 (stinks) as cutting fluid with plain SiC paper. Note that use of loose paper helps to reduce amount of real estate needed for sharpening setup - only one flat is req'd.

   Suggest you might try just that - plain wet-or-dry on 3/8" or 1/2" plate glass with water or light oil. That should be a nearly guaranteed flat surface, and should accurately reveal the condition of your chisels' backs. 60 grit is a good place to start if they're bad. I usually hit the backs with 600 for first time inspection, just to avoid doing unnecessary damage. If they're poor, then it's off to the coarse stuff. (Not as sophisticated an opening touch as JazzDog's, whose opinions I relish, but 600 has seemed fine enough to polish out rather easily, so I've not gone further.)

   I agree entirely that "scary sharp" is quite outstanding. Relatively inexpensive, very fast and accurate, renewable surfaces - there's no method with better results, in my opinion.

   Good luck!

   ---John

   
   

   ---

   Edited 9/23/2005 6:56 pm ET by PJohn

6. 
   douglas2cats | Sep 24, 2005 03:09pm | #8

   You didn't mention, so I'll ask - what direction are you orienting the chisel? With the handle towards your body, or out to your side? I've had better results with the 2nd method - just running the first 1" or so on the glass with the rest of the chisel sticking off to the right. Like others mentioned, unless you put some bad nicks in the edge you only have to do this once. I've tuned up some really crappy chisels that took 1.5 hours or so (each) to get the backs flat. Thankfully I dont own them. I volunteered to sharpen my uncle's set (little did I know!). I usually eyeball the machining marks and take a stab at how fine a grit to start with. Then after a few minutes I can see whether that's going to work, or whether I need to start switching to lower grits to get it flat or get rid of deep scratches or grinding marks. I've also had to go as low as 60g on some of the worst.

   Waddaya mean it wont fit through the door?

7. 
   kesac | Sep 25, 2005 06:26am | #9

   Sounds to me like you are trying to hard.  I very seldom sharpen new tools all at once, as it starts out as a bit of a tedious process.  I can't tell from you description what you might be doing wrong, but go use those chisels for a while, and come back to the sharpening, when you are cogertating on some other problem.  I have had table saws that wouldn't square up the first time, and I don't know that I did anything different, but some where along the line, they straightened right up.

   Scary sharp works great, just like several other methods.  When using sandpaper or other soft abrasives, pull away from the edge, rather than slicing into the abrasive to keep the paper from humping up on you and rounding off your edge.

   I have some sorry chisels that have turned out to work just fine, and I have one Record, that I just keep for the ugliness of the Limey workmanship.

1. 
   philip | Sep 25, 2005 09:13am | #10

   I cannot understand how some folk have the patience to flatten chisel and plane backs by hand so laboriously.
   Whenever I have had the need to sort out newly acquired chisels or plane irons I have used this method, which may be of interest particularly for those who have a lathe:-
   I have various disks which can be bolted to the face plate of my lathe: I merely glue on siliconcarbide wetordry grit 320 or so (not too fine) and select a slow speed and hold the chisel pointing down -it can't get too hot or you will let it go. Sometimes in the case of plane irons I hold them using a machinists magnet. This gets it flat-you will confirm this when you go to your oilstone.
   As an aside , this is also how I sharpen twist drills-have found it to be preferable to using the traditional grinding wheel.Philip Marcou

8. 
   paddywack | Sep 25, 2005 03:39pm | #11

   Are your stones flat?