17 October 2014

Knives: Sharpening angles

Personally I am an angle extremist as my main (vegetable) kitchen knife has a micro bevel of 14° (or 7 degrees per side).  Great but this time I wanted to sharpen a camping knife,  so which angle to choose?

Googling for data I get the following.  Looks good  ...  although 35° that's not much for a cleaver ... are machete in the same category as cleavers ... then I got it, these are sharpening angles, so the edges start at 24° to go up to 70° ...??? ... Welcome to the 21st century!

Second attempt and back to last century,  I took The complete guide to sharpening by Leonard Lee (1995).  I found a rather pragmatic approach:  for kitchen knives anything between 10° (5 dps) to 35° where the major aspect is finding an angle that is easy to reproduce when sharpening.
For camping knives he proposes 30° when whittling and 15° when mainly handling meat. I am not sure I agree there as I expect that when cutting meat from bones there is more strain on the edge. And a blade that doesn't 'bite' the bone too easily is more comfortable.

Looking at factory angles
Morakniv  knives do talk about angles, they are not in microbevels and propose 23° (12 dps) and 27° (14 dps) for their heavier 3.2mm (1/8") thick bushcraft knives that need to withstand batoning.  It is surprising they go to the American bushcraft market with anything thinner than 1/4". They are probably more hard headed traditionalists than marketeers.
Opinel knives, I couldn't find anything on their site.  Someone talked about 25° as recommended by them,  a sharpening angle so that's 25 dps.  It sounded so ... 21st century that I checked.  It's true, the picture shows the main reflection from the convex blade, but at 25° there is the reflection of the micro bevel.

Now why do I think 50° (25 dps) is excessive.  When looking at plane blades I see angles of  25-35° used with the blade off center, that is not in cut but rather a scraping movement and regularly slammed with great force (6# of plane and the guy behind pushing with his two hands) against knots that represent a localized high resistance point. Apart from chopping bones there is not much worse than that.

On youtube I found Canadian Cliff Stamp talking about Edge retention as a function of micro-bevel angle
and offering new perspectives on optimal angles.  He's someone who seem to spend his free time sharpening and cutting truckloads of wood, cardboard, rope and old carpets to assess his sharpening. This delivers interesting work and results.
What he says is that edge retention increases with smaller angles up to some usage-user dependent tipping point. On the graphic 13 dps does 4 times better than 25 dps.  I guess that the graphic stops at 13 dps because he uses a Wicked Edge sharpening gig to set precise angles. Thus losing the ability to go for low angles, the jig being a 21st century product and all that. The Wicked Edge minimum of 13 dps is a lot more than the Leonard Lee lower limit of 5 dps.
The reason behind the improvement are twofold:  low angles cut with less strain so less wear and they offer more 'meat' before the edge becomes too blunt.

So the micro bevel for the camping knife? Whatever I want,  maybe 30° (15 dps) to follow Leonard Lee, probably less.


30 September 2014

Fast holdfast

I got hold of a French holdfast with cam lever.  Having already mentioned them in a previous post,  I found one on a French second hand list and got acceptable shipping costs.  I imagine it as an early seventies model.
It weights 2,5kg (5#).  So it's maybe heavy enough to be set without hammer,  but in practice there is too much play in the hinges to throw it in place.

Not that setting is a problem,  the promise of a one handed operation is fulfilled. And there is plenty plenty of room for even more pressure.  The only problem is maybe the weight, disengaging 2,5kg out of a narrow hole is nothing light.  I glued a thin strip of soft wood (populus nigra) under the pressure point, to give the holdfast a softer touch.  An iron fist on a poplar shoe.


The model is still sold under a more modern form ... that's more the eighties (?) as design.

It looks as if they use a thread,  so it's already close to the 'English' model from Axminster but with the handle in between and not on top. And Veritas too does something similar.

And now that we are at it Sjöbergs has a different approach for something similar,  but it works nevertheless




08 July 2014

Knives: EDC knife usage

After presenting his everyday cary (EDC) Adam Savage worked at a holder for his Leatherman on youtube. So yes those shiny pocketable knives and multitools,  I think I need them,  but what for?

Every day use like opening packages and letters,  cutting fruit, ... and many other things, I hear. So I went for youtube in search of the 'many other things' as  there are many EDC knife demonstrators there, daily carrying up to five blades.  Listing what I heard the main usages for a knife are: showing one more knife, repetitive fast one handed opening, tactical use, cutting paper and battoning. Yes, and on youtube the main usages of a plane are making thin shavings from a perfectly flat scrap of fine wood and setting them on display shelves.  So the knife usages:

Showing one more knife
To do that I ransacked my storage and came up with some, and for good measure bought two extra online.
From the seventies, my camping knives: A non locking folding knife (a nameless hippekniep),  his Opinel n° 8 replacement, a second thoughts Opinel n° 10 (4" blade),  just to be able to cut bread decently. I added now a new shiny stainless Opinel.
A pocketable-keychain leatherman, pink for a good price, but then I have to find a use for pliers.  Maybe it's more something for fishing.
Two pocketable Victorinox.

Fast one handed opening
I can one hand open my Opinel in maybe 4 seconds (with and without usage of the Opinel knock),  but that's way slower than American knife slingers and the closeness of my thumb to the edge would get too much attention of the youtube safety brigades.  Although ... there is no such thing or rather I am part of that posse, having seen so many people slide their fingers over blade edges. It's sharp or it isn't, there is no try. I found sharp with my first, factory sharp, Opinel, using just the weight of the blade (0.5 oz).  Sharp is safe, they say, whatever safe is.

Tactical use
The stab and slash jobs. Many American knives have a tactical look and are categorized as such,  but apart from that I do not hear much self incriminating talk or demonstrative tactical usage on EDC youtubes.   Personally I had some formal knife fighting training,  but in practice I am even too slow to run away. Anyway what I can legally carry here are knives as a tool not as a weapon.

Cutting paper
I am not so good at sharpening but yes it's not a problem if the test is on thick enough paper.  Shaving is another story, although I like to quote the following "I have found the diameter of human hair to range from 17 to 181 µm" to explain part of my problem. I expect the thickest hair to be 1000 times stiffer and way easier to cut than a thin hair.

Battoning
I made many campfires without any knowledge of battoning (that's using a knife as a froe but without any leverage) even if I have to believe youtube, it is the main bushcraft® knife skill together with the use of ferro rods on the back of the knife. On the other hand splitting wood to make a Swedish torch seems a good way to make a smokeless, low maintenance fire. [edit]Seeing later on a Mors Kochanski presentation I was pleasantly surprised to see more than the usual bare bushcraft® basics.

Eating fruit
Rather not.  I can of course, and for example an Opinel does a decent job.  But I usually cut fruit and vegetables with a low angle blade (7+7=14° micro bevel), so a more standard edge (up to 20°+20° and more), even razor sharp, doesn't cut it, it just splits.  The added problem is the need to clean the blade before closing the knife.
A Japanese knife person, Virtuovice made an illustrative video of the apple problem on youtube with one of his hunting knives.

Opening packages
I receive my packages on a predictable place and that's close to my kitchen parring knives. The only way for a pocket knife to enter the competition is a fast one handed draw.  Speed is what Adam Savage was going for, with his multitool belt holder.

Cutting ropes
As a boy scout we did extensive amounts of rope joinery.  The only tool needed is a saw and a knife (or scissors) to cut rope.  Cutting rope with an axe was the alternative,  but things can and will go wrong with an axe and then the whole joint needs to be redone.

Hunting
A good use of a knife,  I think that cutting meat is one of the main traditional reasons to carry a knife, but it is not my problem.  Surprisingly some hunters say to have worked with mid sized, and even out of necessity with the smallest Victorinox knives.

Whitling
Is seldom mentioned as an EDC knife usage, but it's a good reason to carry a knife.

Pen knife
When I asked my father he said that he carried one in the thirties, he used it as a pencil knife as sharpeners where not common then.  Pens where already in metal so no real pen-knife-manship.  The other reason given was tradition, as a part of 'formal' wear.

Maintenance
Sharpening and such, the Lincoln way (If I had eight hours to chop down a tree, I’d spend six sharpening my axe):  The art of knife maintenance.   There is for example a Japanese who thinks that all Opinels even the old ones are shiny, he calls it To assembly from degradation of OPINEL it's not only poetic but also very thorough. Me it's all about nicks (I call them serrations) and stained steel. And seeing the stamps and the wood choice, mine are maybe a decenium older.

So?
I decided to try it out by adding to my EDC a smallish Victorinox (with pen) in my pocket, I think the flat screw driver used for prying is more useful than the knife.  Technically: it's the Signature Lite,  where I had the tinner Signature (without light) in mind. I already used each of the five utensils once.  Yeah! ... but mostly at home

On my desk I already had, not a multitool but, multiple tools like screwdrivers and scissors,  I added a shiny Opinel blade to see if it can be useful.





31 March 2014

Number magic

I read the first half of By Hand & Eye,  that's the  George Walker  part, the second half is by Jim Tolpin. I was not too happy with it.  That's the information part of this post,  the rest is sort of a rant.

After some thinking I focused my dislike in three parts - it's sort of a long rant:  American taste.  Whole numbers,  there is no harmony in drawing.  Classical order in columns.

... that was it,  we are a few months later now,  time to create and finish that post.

Whole numbers,  there is no harmony in drawing.
I liked George Walker post about the Golden Rectangle where he exposed that the close relatives of the golden rectangle: 3:5 and 5:8 feel just as right. But as I discovered through the book, for him it is about the exact whole number proportions,  where for me it's about the ballpark of the golden rectangle.  And that's where for me drawing differs from music.  If in music proportions 2:1 (octave) 3:2 (quint, violin tuning) 4:3 (quart, guitar tuning) ... can be very precise,  I don't know if we need or can achieve a similar precision of proportions when just looking.

American taste
Even if we share much in common with USA-Americans,  it's for example difficult to not see the Simpsons every day - even dubbed in French, sometimes there is a difference. The book uses three pictures of a high boy to ilustrate design.  For me it's a good example of weird looking furniture.  It looks as a semainier, a small seven drawer chest.  The square body  is set on overly curved legs,  probably animal legs,  going for a baba yaga style.  With its legs the top drawers stand too high and are inaccessible.
To finish there is a top that makes me think of a French pre-revolutionary hair piece, unsurprisingly as the periods agree.  The whole can be seen as anthropomorphic,  with its legs, waistline, round faced central top drawer and hairpiece. And with anthropomorphism we go Disney style.
To be fair we have here in town also an overdecorated period (17th century) thing,  probably never liked by everyone. Specifically in may 1944 a keen eyed pilot followed tram tracks towards the church and led it's bombers flight into hitting the church (hitting the center preserving the front) and many other things,  missing their target, the large railway station covering a surface of over 40 football fields, 1km east. The google earth picture shows the narrow street and church on the left and a small part of the railway station right.

Classical Order in columns
Classical fronts are uncommon here, classical columns as discussed in the book, are nearly inexistent.  My house is an exception it got a neo-classic redesign and front in 1830+ without columns. But things changed overt time, in 1950 for example the first floor lowered it's ceiling from 4m to 3m, impacting the appearance of windows. So it's not a pure classical form anymore.
As far as I know there is only one example of columns in town,  also dating back to neo-classic tastes of 1830+.  And as the picture shows it is preserved architecture,  as the building has already been recreated a few times and this time only the front was left to stand. But if I measure the size of the building - order depends on size,  I could check if this is the classical order of Vitrivius or Alberti, Serlio, Palladio, Vignola, De l'Orme, ... ,  but then and now a building is more than exact  proportions.

Being me, I am more interested in the origins of the Doric order rather than its standardized proportions. Certainly the functional wood origins of what would become later decorative aspects.

What I do share with the book is a liking of classical sophisms, here I think to have found one:
"Ornament and mouldings must have a function. While we think today of function as primarily a structural element (a way to meet a physical requirement), the craft idea of function was much broader, because the definition of function included visual appearance."

 Next time I hope it will be about a book I do like.  But then maybe I prefer talking about books I don't like.