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Tool sharpening

Discussion in 'Setup & Repair [DB]' started by toman, Jan 12, 2004.


  1. I thought I'd ask the advice of some of our luthier types; As I slowly build my collection of hand tools I'm in need of some sharpening stuff. Looking at catalogs and whatnot is pretty confusing, with all the different types of stones and guides. Seeing as I'm on a very tight budget, what would you reccomend for the very basics, for sharpening things like knives, chisels and plane blades? I'm thinking probably a simple honing guide and an inexpensive stone of some sort, right? I allready have a strop that I use to keep my knives honed, so I'm covered there and I also have a bench grinder; Can I do anything with that? Thanks in advance...
     
  2. mje

    mje

    Aug 1, 2002
    Southeast Michigan
    I'm not much of a lutheir but I'm pretty good at sharpening chisels. This is what I use:

    -Veritas honing guide from Lee Valley Tools.

    -Thick 12" square plate glass

    -Wet/dry andpaper from 200 to 1200 grit.

    The Veritas guide makes it a snap to get a pefect bevel angle and lets you put a small micro bevel on the end.

    I usually start with 320 or 400 grit paper if a tool isn't too dull. You wet a sheet of paper, slap it on the glass and there's your sharpening surface. When you get to the 1200 grit you turn a little knob on the jig and get a micro bevel.

    Yes, an expert can get a better edge by hand sharpening on a waterstone, but for a tyro like me who only works in his wood shop one or two evenings a week at most, this is a pretty foolproof system. Even if you do use them, the glass/sandpaper method is great for flattening the backs of new chisels and plane blades, and flatteing the bottoms of planes.
     
  3. Damon Rondeau

    Damon Rondeau Journeyman Clam Artist Supporting Member

    Nov 19, 2002
    Winnipeg, baby
    Sharpening is a little like German or French bow -- there are slightly different ways of arriving at good results, and there are general principles that guide you no matter what method you're using.

    MJE's method is known as the "Scary Sharp" or dry abrasive method.

    Rather than go through a whole rigamarole of explaining sharpening theory, I'd recommend a great book: "The Complete Guide to Sharpening", by Leonard Lee, founder of Lee Valley Tools and sharpening guru. Great for general principles and the electron microscope photography.

    Grinders, manual or motorized, are for rough work, shaping the metal as opposed to honing it. Motorized grinders are a great way to burn the temper out of tool steel and thus ruin them. I use a rough diamond stone where a lot of folks would use a grinder. Takes me a bit longer, but I don't worry about burning metal anymore.

    Once ground to shape, metal edges are honed using progressively finer abrasives. These abrasives can be stones (natural or man-made, oil stones or waterstones) or some kind of sandpaper.

    Your strop is good for final honing/polishing, especially if you used some kind of honing compound in conjunction with the strop.

    Really, there's a ton of ways to do it. Learn the general principles, pick a method that appeals to you (for money, for aesthetics, whatever) and get a bunch of practice.

    I've got all kinds of sharpening doo-dads I've collected over the years, but these days I usually use just the rough diamond stone for shaping and a two-sided waterstone for honing. I keep the honing stone handy to the bench, because I like to hone a lot while I'm working. I think it's better to hone more often with less fuss than it is to hone less often with a bunch of rigamarole around getting a "perfect" edge. You need it sharp enough to do good work, you don't need it perfect.

    Sharpening is one of those skills that woodworkers are always extending: sharper, faster, cheaper!! You need to find your way of doing it.

    Oh yeah: honing guides are a great idea. Lots of old-timers will scoff at you, saying it's not necessary. IMHO, they will really help a beginner get good results faster. Get a guide that has as wide a roller as possible -- there's a common inexpensive one out there (Stanley? can't remember) that has a roller that's way too narrow. The guide tips too easily as a result.
     
  4. I'm with Damon on the diamond stones. I use a rough one and a very fine and then finish up on a wide 8" cloth buffing wheel loaded with some steel polishing compound. You can shave with anything after I'm done with it. I've got a bunch of gadgets laying around in the shop, but usually I just do it by hand and use my eye for a gauge.
     
  5. Thanks for the tips guys. Seems like the 'scary sharp' method might be a good place for me to start, and then I can pick up some other stuff along the way. Any suggestions for sharpening gouges, since they're curved? I have a set of old turning tools that I'd like to sharpen up and put to use.
     
  6. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    My $.02 on sharpening: I've tried every method I've ever heard of. A couple years ago I became a convert to hollow grinding (thanks to my erstwhile ex-assistant, Zac Martin). I use a super-low-speed grinder with a medium Norton wheel to create the hollow, then hone a secondary bevel with 3 progressively finer waterstones, with the blade in a honing guide. Stropping with compound is optional. Sometimes you want the precision of a stoned bevel without the slight rounding-over that stropping causes. Hmmm, "stoned bevel". I bet Jeff could do something with that...but I digress. If my process sound tedious, I assure you it takes me maybe 5-6 minutes to do a plane blade or chisel. And the grinding need not be done each time I sharpen; most tools can be honed 2 to 4 times between grindings. Kudos to Damon for recommending Leonard Lee's book. It's excellent!
     
  7. mje

    mje

    Aug 1, 2002
    Southeast Michigan
    To those looking to use a wheel: The grey wheels that come on most grinders are good for grinding out welds or burning chisels. You want a good *white* or *pink* stone- and I think the Norton der Schnitzer is using is a white one, yes?
     
  8. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    Correct. But I must warn you that if you put one of these on a normal-speed grinder you are most likely going to burn the temper out of your tools. Some woodworkers are taught to grind a bit, quench the tool in cold water, repeat, etc., etc. But as Lee points out in his book, you should really avoid getting the tool so hot that it needs quenching, because you are ruining the steel. You can still mess up the tool on a slow-speed grinder, but if you are careful and patient, odds are you won't.
     
  9. Whatever you're sharpening, whether it's a chisel, drill, turning tool or anything else, if you grind it and heat it to the point where it starts to change to a straw yellow colour, you may be affecting the heat treat. If it changes to a blue or red, you're definitely changing the heat treat. Tools can be retempered, but it's a trial and error proposition for the layman, (heating to the right temperature then quenching properly), and you have to know the alloy to have it done properly by a pro.

    If it gets too hot to handle while you're grinding, cool it before continuing. Air cooling is best (slow and gradual), cold water is dangerous.
     
  10. Damon Rondeau

    Damon Rondeau Journeyman Clam Artist Supporting Member

    Nov 19, 2002
    Winnipeg, baby
    You'll know if you've taken the temper out. You'll see the nice colours Eric mentions. You might hope for the best after that, but you'll find that the metal holds an edge about as well as aluminum foil does.

    BTW, toman, nobody answered you on gouges. No mystery: to hone a curved surface you'll generally need a matching curve. You can buy curved stones (are they called "slip" stones?), or you can rig something up with abrasive paper and a dowel, perhaps something you cast with epoxy, yada yada...