Replies

1. 
   NormInFujino | Oct 09, 2003 03:46pm | #1

   You're right about the speed. Ordinary bench grinders will quickly overheat the blade edge and ruin the temper of any cutting tool, so generally should be avoided for anything requiring precision (I use a grinder for my axe and pruning shears, and that's about it). There are dedicated power sharpening systems available like the Tormek, but they're pretty pricey. --I've heard good things about the Koch Sharpening System as well, tho it seems to be meant mostly for carving tools. If you don't have deep pockets, best idea is learn how to do it right, by hand, either using conventional stones and a guide (e.g., you might try the Veritas sharpening jig or the General chisel guide , or the so-called "scary sharp method" using sandpaper on a flat glass plate. See Scary Sharp .

   (I'm not trying to flog these particular dealers, they just popped up on a quick search).

   ". . .and only the stump or fishy part of him remained."

   Green Gables: A Contemplative Companion to Fujino Township

1. 
   scooleen | Oct 09, 2003 03:56pm | #2

   wow, thanks very much, especially for those links. 

1. 
   BG | Oct 09, 2003 04:49pm | #3

   Scooleen,

   Just to add a bit to Norm's excellent advise.  Using sandpaper on glass or, in my case, granite is fast and cheap.  As a newbie however, we have a tough time determining when enough is enough.  I suggest you think about having your chisel(s) professionally sharpened the first time to establish the proper bevel and set a standard for as you develop your own skills.  This is not very expensive and for a good length of time afterward you'll will only need to hone and strop your chisels.

2. 
   GHR | Oct 09, 2003 08:00pm | #5

   In most machine shops high carbon and high speed steel tools are ground and sharpened on 3400 RPM grinders. The people there have no problems with heat related problems.

   I don't grind or sharpen much anymore, but I do use a 3400rpm grinder with a white wheel on the tools I do sharpen. With a light touch I can get a edge that cuts as well as a honed edge.

   I am told that in the production turning world (where time is money) several people never use a home just a high speed grinder.

1. 
   migraine | Oct 12, 2003 01:19am | #14

   I use a bench grinder to do my carving/lathe chisels or what ever else if I'm in a hurry.

   But, I do use a silcone carbide impregnated ruber wheel and a felt wheel with various polishing compounds.  Thern again, I do have a makita "wet wheel"  and various japanese water stones, and I even use the sandpaper method at times.  These are what I use on my various paring, motritising , japanese chisels and plane irons with.

   I don't belive in hollow grinding the bevel in chisels/planes, especially japanese laminated steel.  I will hollow grind my "thrasher chisels" and that is because i don't want to spend alot of time trying to remove nicks/chips form rough handling them.  these are the ones that se concrete, nails, etc on a regular basis

2. 
   lwilliams | Oct 09, 2003 06:33pm | #4

   schooleen,

   Grinding is a rough shaping operation. Actual sharpening is done honing on stones or some other abrasive media.

   Be careful of slow speed grinders. I'm teaching woodworking a few hours a week in a small high school and trying to recondition old hand tools for students to use. I wanted them to see me doing this because I want to overcome the mystery of sharpening. The school has an 1,800 rpm slow speed grinder fit with white friable wheels. What a night mare! I'm now doing the grinding in my own shop.

   The Tormek is okay and  gives great results but it's slow, real s---l---o---w.

   Before you spend your money on a grinder that isn't what it could be let me give you a link to a page on our web site. It's a commercial site so, if you object to that, don't go there.

   The link: http://www.planemaker.com/articles/grinding2.html

3. 
   SawdustRay | Oct 09, 2003 08:41pm | #6

   I'm a beginner myself.  I highly recommend "The Complete Guide to Sharpening" by Leonard Lee.  He starts from scratch and explains what "sharp" is and how that is dependant on tool and use.  I also took a class at Woodcraft Supply - it helps to see someone do it.

   Good luck.

4. 
   DaveBarker | Oct 09, 2003 10:29pm | #7

   Hi,

   I use an 1800 rpm bench grinder to sharpen my chisels and plane blades. I don't use any jig, just do it by eyeball. As I get close to the final edge, when the metal is getting thin, I dip the edge frequently in a cup of water to keep the blade and then use a very light touch against the wheel.

   I generally don't hollow grind either, and I use the side of the wheel to get a final surface-ground edge on the blade. The key is to use light pressure and keep the edge cool with oil or water. I stop when I get a burr on the edge, then strop on a piece of leather.

   It probably wouldn't be a bad idea to practice on a couple of utility chisels to get the hang of it. Everybody has some of these don't they? (used to scraping paint, old gaskets, cutting nails in two...)

   I think learning how to sharpen your own tools is as important as learning joinery. But there's lot of different methods. This is just mine.

5. 
   mike4244 | Oct 09, 2003 10:39pm | #8

   I would like to add one tip to the other posts. If you are using a 3450 rpm grinder and you want to slow it down, let it come to full speed and then shut it off. The wheels will slow down as you grind, then come to a stop. I use this method to grind turning tools and small or thin tools. I also use a friable wheel.If you have a small amount to grind this is a good method , more control because of slower speed.

   mike

6. 
   eddiefromAustralia | Oct 09, 2003 11:45pm | #9

   Hi,

   Can you sharpen chisels on bench grinder

   Answer is a definite yes! - You don't need the expensive systems, just a bit of focus on what you're doing so you don't burn the edge.

   Larry's link summarises a lot of good points on how to use a grinder. 

   There are two speeds of grinder, one works at 1800rpm, one at 3600rpm.

   I use a 6" grinder at home and works well.  I was trained to use a white wheel, but at work we use a black wheel - when not dressed it will burn a chisel quickly.

   The white wheel is a bit more forgiving.

   The only point that I'll add to Larry's post is that you don't force the blade onto the stone - pretend you're shaving the thinnest sliver off the wheel and move the blade side to side - before long, you'll have the edge right.  Be careful not to over heat the edge as it gets thinner, less metal to take the heat away, so it can overheat quickly.

   Cheers,

   eddie

7. 
   Trees2dust | Oct 10, 2003 04:42am | #10

   I sharpen my turning chisels on the grinder and sometimes use them as-is, without honing.  Cabinet making chisels on the other hand get a hollow grind using the grinder, then a honing through various grits of silicon carbide paper on glass.

   You will hear lots of people say that you have to use a slow-speed grinder with a white, pink, blue, whatever wheel so you don't burn the edge.  I have been using my $10 garage sale grinder- a 3600 rpm 6" and it does the job time after time, never ruining an edge.  I did replace the original fine wheel with a friable aluminum oxide wheel, but the original silicon carbide course wheel still gets used now and then.  The key is to use a wheel that is not too fine (60 grit is ok, but 120 is way too fine) and dress it frequently.  Use a light touch, and you won't have to worry about burning the edge. 

   The slow-speed grinder-white wheel thing is a myth.  The most important part is the operator- the operator has to dress the wheel frequently and use a light touch.

   Here's a funny story: at the last turning demo I attended, the host provided an ideal-looking grinding setup for the famous demonstrator- a Delta 8" slow-speed grinder with white wheels.  Believers of the myth drooled at this set up.  The demonstrator cursed the grinder all day- the wheel was so fine that he had to push really hard to make it cut.  He said he'd rather have a fast grinder with a 46 grit gray wheel.  Sounded like he was wishing for my $10 grinder.

   Rick

1. 
   scooleen | Oct 10, 2003 03:01pm | #11

   wow, thanks for all of the imput guys.

1. 
   jazzdogg | Oct 10, 2003 08:01pm | #13

   Scooleen,

   The master woodworker who taught me how to sharpen provided a simple admonition that I've always remembered: Use a light touch, a steady rate of feed, and touch the tool near the cutting edge frequently with your fingertips: if you don't allow it to become uncomfortably hot to the touch, you shouldn't have to worry about ruining its temper.

   You might want to read what Leonard Lee has to say about damage caused during grinding (cracking that's invisible to the unaided eye) under the rubric  "To quench or not to quench"  on page 21 of "the Complete Guide to Sharpening."

   Good luck,Paul

   Whether you think you can, or you think you can't, you're right.

8. 
   JeffKurtz | Oct 10, 2003 05:04pm | #12

   Guess there isn't a whole lot to add than to suggest you practice on some old tools or even scrap steel.  We do so with wood, but for some reason often attack our good tools after little or no practice.

   I started out using a guide, but seldom use one any more.   Not a bad way to start, but I wouldn't advise spending too much on one.

   I think the best advice you've been given is to use a light touch.  To that I'd add: keep the tool moving.

   Jeff

9. 
   nigelUsa | Oct 12, 2003 01:39am | #15

   Check out the craftsman wet grinder for about $40. runs slow and you can keep the wheel wet to cool the tool being ground.