23 December 2014

Layer on layer

Open post #5 dating back from September

A post about a technique that looked counterintuitive to me, repetitive layering.  Maybe it is more a finish carpenter technique.  Anyway it is nicely illustrated by Jon Peters with the build of a blanket chest.  He starts with a box and then ads a frame, feet, ... and ends with a detailed chest. Nice work. jonpeters.com

21 December 2014

Lure and lore of the framing square

Open post #4 dating back from September

Framing squares with their sides filled with tables and numbers are attractive.  Maybe because in my mind they share something with rune swords.  And that's of course my mistake,  I want magic and it's mainly about math.  To get the swords part right, swords are in medieval literature supposed to rely on relics not text:  E! Durendal, cum es bele e seintisme! En l'oriet punt asez i ad reliques:  La dent seint Perre e del sanc seint Basilie, E des chevels mun seignor seint Denise, Del vestement i ad seinte Marie. (Turold 1080)  That's the fantasy part, in real they probably relied only on a hard edge.  I can imagine that rune swords are just like framing squares mainly a 19th century invention.

Now OK, I did look at the framing square maths.  As I was curious enough I studied the tables and numbers.  It's interesting but it doesn't relate to anything I ever did.  Stairs for example are mostly made here with steps between the stringer,  not on top.  The advantage of seeing inches on the square as scaled down feet is also probably lost if I use a metric square.  So I have a book, but not the square.

When making structures with diagonals nowadays things have changed.  Compared to 40 years ago I now have calculators, excel sheets, tape measures of more than 2m and no need for a plumb bob. I would probably be better served with something like an alpha square to solve angled framing problems.  There is a good video about precise measurement cut with a chainsaw using a long tape measure and an alpha square.

Looking for framing square information on youtube I discovered Mark Harmon implementing a low math framing square for framing composed hip roofs: The adjustable hip square.  The square is made to set out 45° hip and valley rafters. To simplify calculations the frame scale is offset by a √2 factor so that the orthogonal values can be used when measuring diagonals.  And by keeping that scale and measures to the horizontal, the roof angle doesn't change the values either.  The only problem is that the measures are stepped,  giving most probably cumulative errors.  A specialized jiggery,  but it looks like an attractive low math solution for one type of problems.  

Of all that lure I acquired a Stanley adjustable quick square to serve as a sliding bevel. I offers me a locked angle together with its complementary angle (90°- angle).  It's jiggery, but I know I sometimes miss the complementary angle on a sliding bevel.  Now what about my next problem, the halved angle?  There is certainly a jig about that too.  Maybe all I needed was a good protractor.

14 December 2014

Wood pecking

Open post #3 from June

Walking in the woods in I saw that someone found a woodpecker in a tree and many other animals.

A little further I found a white-red GR marking (tree on the left) of a long-distance Grande RandonnĂ©e  footpath,  following that trail could have lead me over France through Spain. Compostella, Gibraltar, ....

But there are plenty of short distance alternatives too.  The number  on top allows to walk by numbers over a grid.  There is also a more global grid for cyclists.

Walking by numbers
Cycling by numbers

12 December 2014

Wooden planes - Japanese

A late seventh post in a series about western wooden planes

Thanks to the possibilities offered by ebay I unexpectedly added a Japanese plane to my collection.  The plane was described as 1940's Japanese Old Wood Plane Tool Carpentry. It was offered at a very good price and after a two month wait,  I finally got it home. No complaints about the quality,  no notable bedding problems, no cracks, the only special part is the blade geometry.  Where I expected to see flat surfaces,  I found a lot of curves.  First a secondary bevel just on the lamination,  making it difficult to see if it really is a laminated blade (it is) or a cheaper massive model.
But there was also a curved primary bevel. It will take a number of iterations to straighten the blade and to improve my sharpening technique.  A great help is the youtube series by Sumokun about Japanese planes,  and the faint memory of a Japanese carpentry session.

The not so flat bevels made me think about cupped sharpening stones.  That's not what I expect from todays Japanese blades, but fifty years ago thing could have been different.  Paul Sellers presented today a first post about past cupped sharpening stones.
The same could have been the case in Japan.  In a video 17th Generation Yoshimoto Bladesmith Murray Carter works fluently with a cupped natural stone and expresses his unwillingness to waste stone by just flattening it. He seems to favor controlled wear to get stones flat.

Back to the plane,  with three parts a wooden body and two blades it is a most simple plane.  Setting it up a new plane is probably less simple as every part needs a perfect fit.  The blade for example is wedge shaped in width and thickness.  An extra problem is the width of the blade,  it is certainly impressively wide but it makes everything more difficult to handle. It is a lot wider than my 5 cm stones (2") and also probably than most sharpening jigs.  So if bought  new I would have taken a narrow model. In the meantime I still need a few sharpening sessions to get the blade right and some patience to see how the plane sole stabilizes to the local humidity.