26 April 2011

Saws - Reciprocating (Sabre)

Today I moved three reciprocating saws in and got an armful of saws back from the repair shop.  We use them for pallet repair,  some chops seem to use bandsaws or mighty robots,  but these are certainly good at cutting wood and nails.
The Hitachi is end of life,  no one wants to use them,  so it will hang around for some time.  The Flex model (1200W) is good but we are moving away from it.  One out of six users prefer the Dewalt DW 311 - 1200W.   Four out of six users prefer the Makita  JR3070CT and its  1500W (that's 2hp and if you divide W by V you get A or is it P by U to get I).  Another possibility is that the Makita Active Dynamic Vibration Absorber makes the difference.  "Damien get more Makitas next time",  I ordered two extra.

11 April 2011

The Anarchist Woodworker

Life would be boring without Chris Schwarz. Today he presented an excerpt of the upcoming book The Anarchist’s Tool Chest: A toolchest in 13 rules. As anarchy can mean "without ruler" short of reading the book, I was looking for a meaning.

Searching the web I found a obituary for John Brown by Phil Davy, and I think this gives the context of the title of the book: ...a new practical series called The Anarchist Woodworker. Aimed at the novice, John based the features around a kit of tools he put together from the Axminster catalogue, building projects for the workshop along the way. .... His toolbox remained firmly shut most of the weekend, although he was happy to discuss its contents with anyone he deemed a genuine hand tool convert! ... http://www.getwoodworking.com/news/article.asp?a=980.
Where Schwarz book is about: Assembling a reasonable kit of tools so you can be a woodworker instead of a budding tool collector.
[edit] Chris Schwarz confirmed in a comment to a post at the Cornish workshop that his book was also inspired by John Brown

Now about the chest. It looks nice and massive. Schwarz comes to Germany to give a tool chest course at Dick, most interesting, but wrong dates, so I pass, leaving it to better woodworkers than me.
The strangest part of the tool chest is the bottom. Schwarz explains that the nailed bottom allows to easily replace rotten boards. As the chest is there to protect tools from rust, a rotten bottom seems something to avoid. Maybe I expect him to add some feet to keep the bottom free from a cold and damp floor?

[edit] Looking further I got a picture of a bottom supported by two rails (battens) or is it a frame hidden by the skirt, so the bottom stands free from the floor, even if it lacks some ventilation. The bottom being cross grain to the sides (or the front and back) and possibly the battens, nailing it is a possible solution to seasonal movement.

[edit 2] In a later video Chris Schwarz shows that, for the bottom of the chest, each board is spaced (using a carpenter square) and nailed, leaving room for seasonal movement.  He probably favored simpler shiplap joints over tongue and groove to keep the bottom closed.

I checked a chest - trunk I own, It is close to a century old. The sides, having handles, are most massive approximately 1/2" thick where the front is thinner maybe 1/3" with a little more at the slots. The bottom thickness is more difficult to check. The whole is covered with linen and painted. By circling the chest with reinforced wooden bands the wet bottom problem is answered. At the same time all the joints are protected by the bands.

I see the chest concept is continued in todays flight cases. The sides are still made of treated plywood, but if the structure is closest to the late medieval chests like those I have seen at Beaune, for the rest it is all metal and rivets.

Where Schwarz's tool chest is still close to a traditional dovetailed tool box as could for example be found in old Egypt. The book Egyptian woodworking and furniture shows an example of a 12th dynasty (1991 – 1803 BC) dovetailed tool box but without giving much joinery details.

06 April 2011

Kung Fu Masters

Reading  Robert Wearing's book The essential woodworker (1988) I thought about the Kung Fu masters. Or was it, seeing another master planing I checked Wearing and thought about the masters?

Why Kung Fu? I checked the internet to verify what an old Chinese said to me long ago about Kung Fu.
Definition 1:  In Chinese, kung fu can also be used ...to any ... skill cultivated through long and hard work.
Definition 2:  Kung Fu – an art, skill, mastery achieved in one’s free time.
Definition 2 is close to what she said,  Kung Fu, being free time, refers to a hobby and not only to Bruce Lee.  The essential woodworker of Robert Wearing is aimed at amateurs and as it is often the case, the master is a professional.  One's profession is another man's kung fu.

I studied Aikido and the masters thought sometimes about Ki and also about stance, tension, balance, hold your sword like a bird,  loose those shoulders, straight upper body, knees and toes in the same line, start moving from the hip, less tension in the arms, keep the arms close, .... , forget the books go practicing.  I also studied fencing and the master said: loose those shoulders, body straight, ...  Went to a Tai Chi lesson and  I heard: loose those shoulders,  body .... .  ...?  Are you saying I have a cramped style?

What does a master say about planing.  "Feel for the catch ... push forward steadily,  ... do not ...swing."  "Strong downward pressure..."  (so much for holding a bird)  When needed he keeps the elbow tucked pushing only with the body trying to avoid arm's length  pushes. (good Aikido).
Seeing his leg position he probably shuffles (right foot first?) along the bench without crossing his legs.  For wider boards the situation is  unclear to me,  does he take short strokes to minimize walking or does he keep his full length strokes? (forget the books, go practicing)

Where pushing is good Aikido,  Japanese planes are mainly pulled,  presenting us with another school.  I think both are applicable, to start pulling in a pushing exercise often gives good Aikido.  For short strokes pulling a plane feels correct, although a hornless wooden plane feels more appropriate than a Stanley. Or maybe not as Frank Klausz moves his wooden horned smoothing plane in all four directions when finishing a drawer.

Other masters display even different styles,  most handtool workers are amateurs and we can keep up the more powerful Kung Fu styles for a few hours.  It may look like a session at the gym where we go for the heavier N°5 1/2 and swing it fast at full arms length.  There is nothing wrong to favor push ups.

I know, I mentioned Aikido.  Come on, that's  showcase fighting. It's like looking at the shavings, not the board.

01 April 2011

Sharpening - Leonard Lee

This is the fourth of a number of posts about sharpening literature.

Leonard Lee (from Veritas Tools) published The complete guide to sharpening in 1995.

Flattening geometry
But first the origin of this post,  being as often a Christoper Schwarz post.  In a recent post he favors diamond based over stone-based flattening systems for flattening his waterstones and oilstones.  The problem with flattening stones being the near impossibility to keep them flat.
Before I even heard about Japanese waterstones or Belgian slate I took some interest in stargazing.  This interest is too recent to have seen the numerous workshops about telescopic mirror grinding. Today mirror grinding lost most of its interest as  it is easy to find large finished mirrors and telescopes for the price of the material, where 30 years ago it was possible to first grind a decent 6" mirror and while learning continue with a 8" or 10" .... 40"  in search of the 'big enough telescope'.
What's interesting in mirror grinding is that by randomly sliding two pieces of glass over each other it is possible to get a spherical mirror,  and then by adapting the technique achieve a parabolic, micrometrically or rather interferrometrically precise, end form, where a mirror finish does not mean finished mirror.

All this to say, the stone-based technique used to flatten waterstones is very close to the one used to grind hollow mirrors.  So it is not a surprise that flattening is rarely a success.

Flattening stones
Now Schwarz uses in his post a hammer to 'flatten' his Norton flattening stone and, looking at the technical evolution of amateur telescopic mirror grinding, that's a good idea (this is the april 1st  part of the post). Why is this a good approach? To keep prices low when grinding telescope mirrors, the second piece of mirror quality glass used as grinding tool can be replaced by a cheaper ceramic tool.  A cheap way to make this tool is to use some small 1" ceramic tiles from Home Depot, to ensure they are beveled, to lay them flat on the future mirror (the flat surface) and to embed them in dental stone or something equivalent.  Using small tiles and laying them on a flat surface, avoids any important flatness errors to be found in larger tiles.

The book at last
In his book Leonard Lee covers this flattening problem, he favors diamond plate but addressing the 'poor and parsimonious' comes up with a solution for stone-based flattening systems “These surfaces will always be flat if you are using three stones in rotation”  A good idea, but how can I implement it? The only reference to a three stones flattening system I found is documented by ERic In Nova Scotia. He uses three waterstones 1000,  4000/1000 and 8000/1000.  The flattening is done cautiously between three 1000 surfaces. As I am not in high precision sharpening (yet) it is not for me,  but it offers a good solution where you invest only in primary sharpening stones and not in stones to keep your stones flat.  Back to Leonard Lee,  he offers other flattening alternatives: sandpaper or plate glass and silicon carbide adding eventually a hard platic sheet like  Mylar to bed the particles.

Unusual in the book is a stand against quenching.  "As a general principle, quenching ... is a substitute for good technique.  ... the cracks may become invisible but they will be there." So every time someone mentions quenching,  I think now, yes but ... .  Also undercutting hollow bevels by using small <=6" grinding wheels is covered.

The complete guide to sharpening is impressive and reflects a lifelong involvement in woodworking tools and all things sharpening. It also offers by its variety a lot of coverage for real world technical problems.  For example,  I have an old wet grinder, but it is not a Tormek that offers a smooth and straight operation out of the box.  Truing of a grinder stone is covered.  In Leonard Lee's book I sometimes miss detailed enough instruction.  When sharpening a back saw,  I looked elsewhere for the final details.
As a conclusion I would say that the book will really prove its value if I stop buying any other sharpening books, it's time to be more parsimonious on the book front.