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is your mora too sharp?

Discussion in 'Edged Tools' started by robin wood, Mar 29, 2008.

  1. robin wood

    robin wood Bushcrafter (boy, I've got a lot to say!)

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    Now I am not an expert or a knife maker and am still learning a lot about what makes a good using knife. I use knives primarily for woodwork and am searching for the best blades and grinds for that job and have learned a lot particularly from some of the Scaninavian users on British Blades such as Edge Pal. There are folk there who have carried and used this sort of knife every day for 50 years.

    During this learning process it has occurred to me that the standard sharpening method (Ray Mears style flat scandi hone following the existing bevel) on the standard cheap bushy knife (Frosts clipper/mora) may not be the best.

    Here is a brand new clipper, angled so the light reflects off the bevel.

    [​IMG]

    Now if we tilt it a little away from the light we see this.

    [​IMG]

    See the tiny secondary bevel reflecting the light? Here it is close up.

    [​IMG]

    When I measure the primary bevel I make it about 22 degrees, when I do the tilt to get the light reflecting off the secondary it feels like I am adding about 5 degrees which added each side gives a total edge angle of 32 degrees. This is a very strong edge but because of the thin blade and narrow 22 primary grind it still passes through what it is cutting with far less resistance than a 30 degree bevel scandi on a thick blade would. It makes it an ideal general purpose knife for a bit of food prep, at a push you could skin, gut fish, carve wood, batton to split knindling and the edge would hold up.

    Now what happens when you follow Rays sharpening technique, put it on your waterstones and hone on the existing bevel? Well to start with you will actually be doing nothing at all to the edge, just polishing the primary bevel, the small secondary will keep the edge from touching the stone at all. Then when you have finally worn the big primary all the way down and start removing metal from the edge then go through the grits to hone that edge to a mirror polish what have you got? "Shaving sharp"? "Scary sharp"? Well what you have is a knife that was designed to hold a 32 edge with a 22 edge, it will shave the hairs off your arm and impress some people but it will not hold that edge any where near as long as the original.

    Now perhaps folk think they know more than Frosts or think that Frosts are incapable of putting a proper scandi edge on a knife? No, that secondary is there by intention after an awful lot of research and testing, I know I have toured the factory and talked to the owners. This is a Frosts 106 sloyd knife grind out of the box.

    [​IMG]

    The striations parallel to the blade are the oil coating, the blade is almost mirror polished with no secondary they could put that on the Clipper if they wanted. This knife is specifically designed for woodcarving, it is not a general purpose knife, the bevel is 25 and at 61 Rockwell the core is harder than the clipper to hold that fine edge.

    So if Frosts wanted to have a scandi grind with no secondary on the clipper I suspect they would put it nearer 30 than 22. Of course if you do sharpen your knife to 22 it will briefly be scary sharp but if you use it much you will get a lot of sharpening practice. Have you removed the secondary on your clipper following the existing 22 bevel? how do you find it performs? How much work will it do before you need to touch it up?
     
  2. Bernie Garland

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    I think your 100% correct Robin. I also put a very slight secondary bevel on all my scandi ground knives,It definitely holds an edge longer and needs less sharpening than a true flat.

    Bernie
     
  3. Shinken

    Shinken Native

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    depends on what you do with your knife, if i am going to be carving green wood i'd zero it.

    Seasoned oak id put a convex secondary on it.

    How can we say that people should or shouldnt put this or that bevel on it? depends on what they want it for.

    Factory's usually go for more durable edges so they get less complaints when the edge rolls.
     
  4. Tiley

    Tiley Full Member

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    An interesting one, this, from two folk who obviously know what they're on about. As a humble (and very ordinary) bushcraft enthusiast, how do I get a secondary bevel on the edge of my knife? Is there an easy way or will I have to keep on practising? That said, I've found that I've been able to do a huge amount of work, both rough and refined, with my Skookum Bush Tool without it losing its edge to any great degree. Does this mean that the 'edge symmetry' on the knife does not need a secondary bevel?

    I have to admit that I do not now use waterstones to sharpen my knife - too many complaints about the mess on the kitchen table from high command. Instead, I've got some of the Spyderco ceramic stones which seem to do the job pretty well.

    I'm sorry to come across as an incompetent but Robin's post has got me wondering...:bluThinki ... :eek:
     
  5. Shinken

    Shinken Native

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    Your skookum probably has a steeper primary bevel so dosnt need a secondary for the jobs you use it for

    Factory's usually go for more durable edges so they get less complaints when the edge rolls.

    If you want it for general stuff then lowest common denominator comes into effect, durable enough to suit the toughest job for the knife
     
  6. Shinken

    Shinken Native

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    An easy way of putting a secondary edge on a knife is to use a crockstick of some sort. do a search for the spiderco sharpmaker.

    You can also make a mini one yourself using a ceramic rod and a small piece of wood and drilling a hole in the wood at the correct angle that you require

    http://spyderco.com/catalog/details.php?product=77
     
  7. JonnyP

    JonnyP Full Member

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    I use a sharpmaker for all my scandy's, shaving sharp plus good edge retention..
    Interesting thread Robin..
     
  8. spamel

    spamel Banned

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    I have a gift from another friend if I need to put a micro bevel on a knife. It is a small pendant that unfortunately broke the day after I was given it, but it glued back together nicely and you cannot tell unless you knew before hand. It is made from jasper I believe, I could be wrong on that though, and based on a viking find. It sits around my neck on a thin leather lace and puts a very good micro bevel onto any knife I've tried it on so far.

    [​IMG]
     
  9. Dougster

    Dougster Full Member

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    One of the main reasons I moved away from Scandi was the amount of time I spent sharpening. I still have a Sandvik clone by Stu M which I love for when I need to carve, but for the most part I use a convex in RWL-34 (again by Stu M). I find for all but detailed carving it is (IMHO) far superior in every task to the scandi, especially for deeper cutting in wood and food prep.

    The down side of this grind is that it took me far longer to get my sharpening skills, but the nature of the shape of the blade and it's sheer hardness mean this task is undertaken far far less than on the scandis I use to use.

    One solution for those wanting a good compromise would be to sharpen a la Mears then use the loose strop he demostrates to hone the knife, this would put an ideal micro convex edge on it.
     
  10. xavierdoc

    xavierdoc Full Member

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    I bought the Spyderco 11,000 grit ceramic stone for gunsmithing originally. It is now used for pre-strop sharpening stage on all my cutting tools except convex edges (use wet and dry on leather for these). It is an amazingly effective bit of kit -keeps flat, too.

    For my thicker, bushcraft style knives I go for a zero scandi grind but strop with compound on linen then leather, putting a slight secondary convex bevel on, augmented with power-stropping where available. My Mora, I use the 11000 grit stone for restoring that secondary "micro-bevel". Works well.

    I don't get on with the sharpmaker as well as many people on here- perhaps I just need to reread the destructions and practice more (seems pretty self-explanatory).
     
  11. xavierdoc

    xavierdoc Full Member

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    Some good points there, Dougster. Your last paragraph seems to reflect what I do for my bushcraft-oriented scandis.

    When you say "...I moved away from Scandi was the amount of time I spent sharpening" do you mean the edge didn't hold, or it took a lengthy sharpening session to get the edge back? I've certainly found "high-end super-stainless" steels pretty laborious in scandi grinds and most of the knives I use in these steels do not have scandi grinds.

    I like a good convex edge but don't use it on knives I would need to sharpen in the field, as in my hands this wood be fiddly and probably frustrating (I have used a small stone for maintaining convex edges but use wet-and-dry on thick leather and wood surface for "proper sharpening")

    Do you sharpen your convex edges at home/base only? If not, what technique do you use for sharpening out and about?

    Thanks,
     
  12. Dougster

    Dougster Full Member

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    As I usually carry my RWL34 and spyder tenacious out and about they really don't need sharpening that often and when using a convex I find the DC4 works better than with a scandi so I carry it in case.

    I also use the spyder stones for convex sharpening too. I must do it all backwards.:rolleyes:
     
  13. w00dsmoke

    w00dsmoke New Member

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    Wow I am impressed but I'm not surprised at what you know. Well done for the explanation.

    I spent hours trying to put a decent edge on an old Mora that I had and could not work out why it was taking ages and then going blunt after I'd used it on some hard wood. I ended up putting a small secondary bevel on that makes it stay sharper longer just like you have explained. :You_Rock_
     
  14. brancho

    brancho Bushcrafter (boy, I've got a lot to say!)

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    Thanks for the thoughts Robin.
    I have a Brussletto blade that came with a small secondary bevel that I keep damaging the edge on and this may be the answer as it is similiar in thickness and angle to a the blades you have shown.

    My Frost clipper seems to cope OK without the secondary bevel but I may put one on it.

    when I think about it the other scandi blades I have bought alll came with a secondary bevel.
     
  15. Hoodoo

    Hoodoo Full Member

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    Most of the wood I carve is seasoned hardwood including walnut, cherry, and hard maple. I don't have any problems carving for hours or even days with knives ground to a zero bevel. The main problem I've seen is the wire edge. You can't always feel it but it will ultimately kill your edge. If you sharpen with the blade going into the stone you will repeatedly make and break off pieces of a wire edge. I don't think this method gives you the finest edge. If you sharpen with the edge trailing, you can draw the edge WAY out to the point where you THINK you don't have a wire edge but the minute you put it to seasoned hard wood, it folds. That's why in my last steps of sharpening, I use a mousepad with 1500 or 2000 grit to lever the edge off. You can actually see it "plate" on the sand paper. Then strop away what remains.
     
  16. TheGreenMan

    TheGreenMan New Member

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    You and Hoodoo, it seems :)

    And just when I was beginning to think I had this honing thing whipped.

    I’m going to have to explore this more…

    Kind regards,
    Paul.
     
  17. BOD

    BOD Bushcrafter (boy, I've got a lot to say!)

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    If i remember correctly, Mors suggests that the knife be prepared like RM but then a micro bevel be added and the blade kept sharp by stropping and a touch up regularly which is what I do

    So I guess you have the man to support what you say
     
  18. canadianwildman

    canadianwildman New Member

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    one bevel for me easy to sharpen with rocks i find
     
  19. G.M. Merrill

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    I always have ap brain block when I try to sharpen a knife with the full bevel flat on a stone. The only time I do such a thing is to thin the edge when the bevel becomes too thick. I learned to sharpen knives in a small slaughter house when I was a kid, there we mostly kept the knife edges sharp on steels and only used a stone about once a day, but when we'd sharpened the blade so much that the bevel became thick then we'd thin the entire blade fron back to edge so it would again take a sharp edge.
     
  20. mr dazzler

    mr dazzler Native

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    On a slightly dofferent but similar note, it was when I put a tiny micro bevel upon my adze that it went from fairly good performing cutting tool to sublime. It is out cannal with the extra micro bevell being the one that rubs the wood when cutting. Effectively making the angle between cutting edge and handle much more acute. The edge lasts for ages, and doesnt chatter like it used to, happily works its way through 2 or 3 inch oak board's, much less effort and much greater accuracy (although the accuracy is also down to 3 or 4 months of intensive spoon carving-using those hook knives has done wonder's for improving my co ordination skill's)
     

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