Is it worth taking the slight secondary bevel off my pukko?
If so flat or convex grind?
Opinions please?
If so flat or convex grind?
Opinions please?
pukko secondary bevel
- Thread starter Pignut
- Start date
I tend to let ot wear/strop out naturally.
Using "agressive"stropping ie on varios grades of Wet&Dry papers strops it out to a gentle convex - my prefered edge these days.
Using "agressive"stropping ie on varios grades of Wet&Dry papers strops it out to a gentle convex - my prefered edge these days.
I had a knife with a convex edge and just could not get it sharp!!
Thought about letting it strop out "Naturally" though how do you keep the secondary bevel sharp, whilst stropping the flat grind, dont they both wear evenly?
If you see what I mean?
Thought about letting it strop out "Naturally" though how do you keep the secondary bevel sharp, whilst stropping the flat grind, dont they both wear evenly?
If you see what I mean?
My W&D is mounted on stiffish kip mat foam so it gives a slightly rounded /convex shaping, blending in the secondary bevel.....
Well I have flattened it and WOW!!!!
What a difference!!!!!
Yes less robust but..... worth the sacrifice!
Cheers Gents
What a difference!!!!!
Yes less robust but..... worth the sacrifice!
Cheers Gents
robin wood
Bushcrafter (boy, I've got a lot to say!)
I am fairly new to this but I have been experimenting with half a dozen different scandis ranging from clippers and laminated frosts to expensive damascus and hand forged laminated Scandinavian blades. Most have come ground around 20 degrees with a tiny secondary bevel with the exception of Frosts 106 which is around 25.
For my wood carving I have always used frosts 106 and sharpened flat scandi with no secondary and it worked very well. I also use Del Stubbs sloyds which are about 22 degrees flat and will hold that edge though they are small so I tend to use them for finishing rather than heavy roughing.
What I have been finding with most of the other scandi blades I have bought is that if I follow the flat 20 ish degree bevel and flat grind it to remove the secondary they come out incredibly sharp but can not hold the edge in use. Some chip but most the edge folds over. My thought is that such a tool may shave your arm but if I want a shave I use a razor, if I want to cut wood, rope etc I want a knife that will do it all day without the edge deteriorating.
The solutions that work for me are either to put the secondary back on with 6-10 strokes each side on the 6000 grit waterstone at 25-30, this gives an excellent general purpose edge which is quick and easy to touch up since you only have to touch up the secondary the one and only thing that it is not perfect for is fine controlled woodcarving (still fine for feathersticks coarse work etc) What works best for woodcarving is 25 degree flat so either buy a frost 106 for that or you will need a complete regrind to take the 20 degree out..that is not an easy project.
There is an excellent post on British blades on this subject here. http://www.britishblades.com/forums/showthread.php?t=51828
Now I have not worked as long on this as Red and maybe in time I will come back to full flat skandi but for now I am definitely a fan of the small secondary for a general purpose knife. I always respect thoughts from folk that use tools a lot and these tools have been developed through hundreds of years daily use, most of us just play really so we can afford to spend lots of time getting edges razor sharp and showing off hairless forearms. I never saw anyone do that in scandinavia.
For my wood carving I have always used frosts 106 and sharpened flat scandi with no secondary and it worked very well. I also use Del Stubbs sloyds which are about 22 degrees flat and will hold that edge though they are small so I tend to use them for finishing rather than heavy roughing.
What I have been finding with most of the other scandi blades I have bought is that if I follow the flat 20 ish degree bevel and flat grind it to remove the secondary they come out incredibly sharp but can not hold the edge in use. Some chip but most the edge folds over. My thought is that such a tool may shave your arm but if I want a shave I use a razor, if I want to cut wood, rope etc I want a knife that will do it all day without the edge deteriorating.
The solutions that work for me are either to put the secondary back on with 6-10 strokes each side on the 6000 grit waterstone at 25-30, this gives an excellent general purpose edge which is quick and easy to touch up since you only have to touch up the secondary the one and only thing that it is not perfect for is fine controlled woodcarving (still fine for feathersticks coarse work etc) What works best for woodcarving is 25 degree flat so either buy a frost 106 for that or you will need a complete regrind to take the 20 degree out..that is not an easy project.
There is an excellent post on British blades on this subject here. http://www.britishblades.com/forums/showthread.php?t=51828
Now I have not worked as long on this as Red and maybe in time I will come back to full flat skandi but for now I am definitely a fan of the small secondary for a general purpose knife. I always respect thoughts from folk that use tools a lot and these tools have been developed through hundreds of years daily use, most of us just play really so we can afford to spend lots of time getting edges razor sharp and showing off hairless forearms. I never saw anyone do that in scandinavia.
Thanks for your input on this!
I have all manner of knives with all manner of grinds and appreciate what you are saying on the fragility of the scandi edge, I dont think edge is that important, in the correct hands a knife of any edge can be put to good use (Pros and cons to each)
I should have pointed out this knife will not be used for heavy work (Leave that for the axe) but will be used for collecting fungi, carving/shaping and probably game/food prep!
I have all manner of knives with all manner of grinds and appreciate what you are saying on the fragility of the scandi edge, I dont think edge is that important, in the correct hands a knife of any edge can be put to good use (Pros and cons to each)
I should have pointed out this knife will not be used for heavy work (Leave that for the axe) but will be used for collecting fungi, carving/shaping and probably game/food prep!
Just a side note but All of my woodplane irons (blades) have a secondary bevel.
Also all my chisels have.
Its recommended in Leonard Lees Complete guide to sharpening with regards to plane blades and chisels and also (unsurprisingly enough considering who makes them) Veritas tools instructional booklets.
Pretty sure its recommended for Lie Nielson tools also
It makes it far quicker to do a quick touch up on the iron and to change the included angle when changing from cutting across the grain to planing curly grain.
Theres a fair amount of quite scientific information regarding this and also different angles for differing grains and I am wondering why it should be so much different for a knife blade.
Basically the angle of the secondary bevel is the cutting angle and the rest is just support.
As long as the angle of the cutting edge is the same I can't see how it makes any difference other than the one with the secondary bevel is simpler and quicker to sharpen.
Anything conclusive or is the evidence just anecdotal?
The angles of about 25 degrees (37 degrees when you include the angle that the iron is bedded in at in my block plane) were best for going across the grain in softwood, going across the grain in hardwood needed a bigger angle (30 or so degrees and thats 42 degrees included ) and for very curly wood its sometimes recommended to have a 50 degree plane irin angle bedded at 12 degrees which gives an included angle of 62 degrees.
This big angle reduces tearout of the wood being planed and none of these irons have a chipbreaker.
Would be interested to see some research if anyones seen it in relation to knife blades.
Also all my chisels have.
Its recommended in Leonard Lees Complete guide to sharpening with regards to plane blades and chisels and also (unsurprisingly enough considering who makes them) Veritas tools instructional booklets.
Pretty sure its recommended for Lie Nielson tools also
It makes it far quicker to do a quick touch up on the iron and to change the included angle when changing from cutting across the grain to planing curly grain.
Theres a fair amount of quite scientific information regarding this and also different angles for differing grains and I am wondering why it should be so much different for a knife blade.
Basically the angle of the secondary bevel is the cutting angle and the rest is just support.
As long as the angle of the cutting edge is the same I can't see how it makes any difference other than the one with the secondary bevel is simpler and quicker to sharpen.
Anything conclusive or is the evidence just anecdotal?
The angles of about 25 degrees (37 degrees when you include the angle that the iron is bedded in at in my block plane) were best for going across the grain in softwood, going across the grain in hardwood needed a bigger angle (30 or so degrees and thats 42 degrees included ) and for very curly wood its sometimes recommended to have a 50 degree plane irin angle bedded at 12 degrees which gives an included angle of 62 degrees.
This big angle reduces tearout of the wood being planed and none of these irons have a chipbreaker.
Would be interested to see some research if anyones seen it in relation to knife blades.
WOW!!!
This is getting technical!
I might look into the whole angles thing!
I am gonna stick my head out of the trench here (Please dont shoot me down)
However A secondary bevel can not be as "sharp" as a scandi in that the secondary bevel will increase the angle on the blade, I also think a scandi type grind is a lot less hassle to maintain!
This is getting technical!
I might look into the whole angles thing!
I am gonna stick my head out of the trench here (Please dont shoot me down)
However A secondary bevel can not be as "sharp" as a scandi in that the secondary bevel will increase the angle on the blade, I also think a scandi type grind is a lot less hassle to maintain!
I was mainly refering to plane irons and can see what you mean about the angle being more acute with no secondary bevel but unless people know what angle they are grinding to with a reasonable degree of accuracy I am not sure if the results are repeatable with differing thicknesses (or even depths) of blades.
I would call this secondary bevel a micro bevel and its only a few strokes on the hone to make it.
When it gets too big I then hone the main bevel till its gone and start again.
I used to hone plane irons freehand but now get far more accurate, repeatable and faster results with my jig.
Faster = more money to me and less time wasted.
Still do knife blades freehand though and always will.
Here is a fascinating & pretty authorotative thread on the subject of Puukkos & their grinds from a guy with alot of experience...
http://www.britishblades.com/forums/showthread.php?t=51828
Edit: just seen Robins post - I concur
http://www.britishblades.com/forums/showthread.php?t=51828
Edit: just seen Robins post - I concur
Think this will never be resolved and each to there own!
I would guess that if you hav a flat grind and strop on anthing other then a flat board you will to some degree get a micro bevel anyway!!!!
My thoughts (To stop this often discussed topic dragging out)
Is it sharp?..............................................Yes
Can you use it safely?..............................Yes
Are you happy with it?..............................Yes
Then good enough by my calculation!
Thanks all for the input!
(No offence to anyone in this thread, if you read any into it!
I would guess that if you hav a flat grind and strop on anthing other then a flat board you will to some degree get a micro bevel anyway!!!!
My thoughts (To stop this often discussed topic dragging out)
Is it sharp?..............................................Yes
Can you use it safely?..............................Yes
Are you happy with it?..............................Yes
Then good enough by my calculation!
Thanks all for the input!
(No offence to anyone in this thread, if you read any into it!
Indeed.
Do what suits you & the task at hand.
Make adjustments to the edge as the work requires & not necessarily as convention dictates.
Do what suits you & the task at hand.
Make adjustments to the edge as the work requires & not necessarily as convention dictates.
I know its a side note to the main discussion but theres a chap thats went into sharpening plane blades to the far end of a fart.
Its further that I would bother but you can't fault his methods.
HERES his info.
I am not saying that anyone needs a microbevel, its just that with plane blades at least they are a practical way of sharpening them quickly that gets the same results as far as sharpness.I was just wondering if there was anyone that has been as scientific about knife blades considering they get used for cutting wood as well, also I am not quite sure how interchangable the terms "sharp" and "acute" are in this context.
Noit in the least bit offended and was only wondering if anyone had found something more than opinions on the matter.
Not saying anyones wrong, just wondering what the facts were.
Regards Scott.
Its further that I would bother but you can't fault his methods.
HERES his info.
I am not saying that anyone needs a microbevel, its just that with plane blades at least they are a practical way of sharpening them quickly that gets the same results as far as sharpness.I was just wondering if there was anyone that has been as scientific about knife blades considering they get used for cutting wood as well, also I am not quite sure how interchangable the terms "sharp" and "acute" are in this context.
Noit in the least bit offended and was only wondering if anyone had found something more than opinions on the matter.
Not saying anyones wrong, just wondering what the facts were.
Regards Scott.
robin wood
Bushcrafter (boy, I've got a lot to say!)
I think a blade with a primary grind at 20 and a secondary at 25 (ex factory mora) will be precisely as sharp as a straight scandi 25 degree. If you remove that secondary bevel and make it straight scandi at 20 yes it will be "sharper" but the manufacturer chose 25 as the best compromise of sharpnes/edge holding ability for that steel and tempering. To change the blade to a 25 scandi is not easy but can be done with quite a bit of work on the coarse wetstones or a jig and a good grinder (I use a tormek). The idea of the secondary bevel is precisely that it is quicker to maintain. By removing the metal from a 1mm wide bevel you get a new edge compared to removing the metal from the surface of the whole primary bevel. having said that a scandi grind is easier to learn to maintain because you are simply feeling the angle that is there and following it.
Very interesting information and surprising to me the size of the angles, my anecdotal experience and that of others that carve wood with knives is that 22-26 is best, I only carve hardwood and do not get tearout. There are two crucial differences I think in how a knife works compared to a plane iron when woodcarving; first when used properly the knife achieves a slicing motion rather than being pushed straight into the wood think of the difference this makes when cutting a tomato, could that have anything to do with how we can get away with a shallower angle and not get tearout? The other big difference and this is why woodcarving knives should not have secondary bevels is that the bevel is used effectively as a jig to control the cut, the bevel slides along the surface it has just cut holding the knife steady effectively doing the job that the plane body does. A 20 primary grind and small 25 secondary is very much more difficult to control acurately. This obviously does not apply when cutting rope, or skinning an animal for either job the knife with the secondary should as I understand the theory perform equally well if not better due to the thinner blade having less resistance..
i would be interested to see that knife research too, there are the cutting competitions popular in the US but its not quite the same.
Totally agree, though it is a fascinating subject the more you know the more there is to learn.
At the end of the day there is no right and wrong, for each person there will be an optimum depending how much time they want to spend sharpening, how much time cutting, what they cut, the steel of their knives and how precise they want to be. The trick is to try to find that optimum for what you do.
I think its also important to reflect on the nature of tasks and the type of cut. The PFK has a very shallow angle and is zero ground but I use it only for slicing and planing cuts. Beater has a steeper angle and convex secondary but is optimed to withstand impact cuts (chopping and batoning). Even in axes my limbing axes are narrow profile compared to splitting axes which are much broader (more obtuse in angle terms). Whether something can have a perfect grind for all tasks I doubt - hence the endless fascination!
Red
Red
Similar threads
