Fabula Lignarius

Month: May, 2015

Using a Sumisashi and Sumitsubo

Upon request of several readers we will have a closer look at how you can use some of the Japanese layout tools I discussed in the previous post.

Snapping Lines with a Sumitsubo

Make sure your sumitsubo is prepared well and ready to go. See this post.

Since we snap center lines we have to mark the center first.

Mark the center by measuring and placing a tick mark.

mark center

Note how I use 100mm at the edge to increase accuracy. The lens of this camera creates a false perspective. It appears that the stick is less then 60mm but in fact it is exactly 60.


Set a marking/scribing gauge to distance approximately half the width of the piece. (about 1mm larger) Mark from either side and you will find the center exactly in between both marks. Very fast, convenient and accurate.

scribing center

Pin the line either to the end grain or on the surface. I prefer the end grain and early wood since it doesn’t leave a hole on the surface and the pin is easier to remove. When removing the pin after snapping twist it while pulling to avoid bending the metal pin.

pin line

You can rotate the pin to get your line spot on your mark. And make sure you tie the line to the metal pin with a halfknot.

half knot

After unrolling you can either grab the line before you place the other end on the mark or place the line down while creating tension on the line, the reel is now locked with your thumb or by the palm of your hand.


In order to make sure you snap a straight line without any curvature you have to hold your head still. Put down the line on the mark, make sure you have the right amount of tension and tap the line in front of you. This creates a tick mark. Now without moving your head you lift the line straight up and snap it aiming for the tick you just made.

The centerline is then marked with a Z-type mark.

Voila, two hundred and fifty eight words later we have…  a line.


Good or Bad

When holding the sashigane to make marks hold it with one hand and bend it slightly to lay it flat on the surface. The friction between the thickened corner and the blade should be enough to keep it in place.

good sashigane practice

good sashigane practice

This might take some practice but avoid using your fingers to hold the blade while marking a line. Sometimes you have to but in general this is considered bad practice.

bad, bad, bad

bad, bad, bad

Laying Out a Mortice

If you align the bottom side of the long blade with your centerline (CL) and mark along the top you have drawn a line that should be exactly 15mm (the width of the square) away and parallel to the CL. Often a mortice is located directly upon the CL. Let’s say your tenon is 90mm wide (which is common) you have placed the long blade with the bottom along the CL and the crossing CL at the 45mm mark. This way you can draw two sides of the mortice at once.

mortice layout step 1

Without moving the square you have placed a tick mark at 90mm.

mortice layout step 2

Use this tick to mark the other short side of the mortice holding the square to the edge of the timber.

mortice layout step 3

Only one side of the mortice remains to be marked and often I flip the square to draw this line since then the short blade has a longer bearing surface on the timber which aids a bit in accuracy.

mortice layout step 4

Mark the mortice and mark the depth if necessary. Eventually you add about 2mm of clearance to avoid that the tenon will bottom out. I Wouldn’t write 122mm, it is something you just know while cutting out the mortice.

mortice layout step 5

All the above takes about 7 to 8 seconds.

Secret Tricks

For what I am about to tell you the guardians of secretive craftsmanship might come and hunt me down. I couldn’t care less and in these times of global industrialism I will do anything that contributes to the continuation of this ancient craft. The last thing we need today is secrecy.

Take a fine file and make a mark on your sashigane at 28mm. You can now quickly use this to mark the offset of the pegholes of your tenons. Seconds saved, consistency guaranteed.

file mark

Invest in a reel of superfine braided dyneema fishing line and replace your sumitsubo inkline with this stuff. They don’t soak up too much ink thus leave a clearer and fine line. They are super strong and last a long time.

Cut back the top on the tip of your sumisashi, it will make it write in both directions which works great when doing layout on round logs.

cut tip

And remember, when laying out always think in function of the centerline!

This post has been a new experience for me and is written in a truly internet-like, how-to, step-by-step-guide way. I hope it will be useful to some. It seems a bit superficial but maybe that is just me being old fashioned. The next step up from here is video tutorials. Cold shivers down my spine when I only think of it. I don’t know I could ever go there, I am sorry. Pictures and text will have to suffice.

In Favor of Sumi

This post is about the practice of laying out with ink. I love it and recommend it. If you are into timber framing and enjoy doing precise work it is worth giving it a try and see wether it will fit your scheme. The tools I have tried when doing layout on wood are scratch awls, markers, pencils, mechanical pencils and knives but when I was introduced to layout with ink (sumi) it certainly was a revelation. So far knives or pencils were my preferred weapons of choice and although I still use them for certain applications most of the time I use my sumisashi (bamboo pen) and sumitsubo (inkpot) to do accurate layout.

my sumitsubo

Learning to work neatly with ink can seem like a challenge but it doesn’t have to be. Without some basic instruction it is likely that ink is going to be all over the place, your hands and face smeared in black stuff. Your pieces of accurately dimensioned lumber looking like something that belongs in The Met amongst the collection of modern art rather then a cleanly layed out piece of wood ready for accurate cutout.

Above you can see the Chinese version of the same tools which I encounteredon a building site during my travels true China. Only one of the carpenters spoke some English and I wished I could have talked to them longer. Their work was a bit rough but they where obviously very skilled. The nice work they did with a limited tool set said more than words could have.

Chinese carpenters square

This carpenters square tells another story…

chinese inkpot

It may be one of the first things I have learned during my initial apprenticeship and I remember making accurate notes about it at night to make sure I could refer back to them later. I never did. I have never looked at any of those diaries and maybe it was the process of recording those teachings somehow seemed essential at the time.

Call me neurotic but it gives me a very satisfying feeling to draw fine clearly visible lines on a piece wood. The whole stick is layed out and I review what I have done in a attempt to eliminate mistakes, that unavoidably still seem to slip in somehow. I get excited to cut out the joints. Splitting, taking or leaving the line aiming for that near perfect fit.

sumitsuke woodblock print

So why would you use this method above any other? Here are my arguments:

  • the lines are the finest
  • they can be removed easily with a slight touch of a hand plane
  • your lines are clearly visible
  • the sumisashi edge is hard-wearing and remains fine for a long time
  • the lines drawn do not disolve with water
  • and most importantly; it is just very pleasant to use

mortice and stub tenon layout

Try to erase a pencil line on a piece of wood and you are guaranteed to make a mess, mar the surface or leave a scratch if you use a hard pencil. Instead a light stroke with a handplane will remove an ink mark and leave a clean surface to continue from. If you snap line with a chalkline or use a fat pointed pencil I always wonder where on this 2mm thick line it is you want to cut? It remains guessing at best. The joint will either be too tight or fit like a dick in a bucket. (This is an official English timberframers expression) And since none of the above could possibly be what we aim for we are in need for a fine and neat way to mark our timbers for cutout.

Avoiding Frustration

I have noticed that some sumi easily turns the silk wadding of your sumitsubo into a rock. This can be really frustating since it takes forever before your sumitsubo is usable. It has to soak all night and would still remain more difficult to use. At first I was under the impression that somehow acrylic might be mixed into it and causes the hardening of your wadding. I recently learned that some sumi sticks are made by mixing charcoal or soot with animal protein glue and this explains exactly the situation described. So what you are actualy looking for is higher grade caligraphy ink made of charcoal.

You can grind your own sumi from a stick but this takes time. Once upon a time I enjoyed gently grinding the stick of sumi until you get the perfect consistency of ink. I soon found out that I rather spend time on other things than preparing sumi, how meditative it may seem. These days I use prepared ink and I tend to choose the higher quality that is used for calligraphy, also here the lower quality ink contains additives such as gum which is undesirable. If you do choose to grind your own make then don’t make it too thick since it will not run as smoothly from out between the fine cuts you made in your sumisashi.

You need a lid.

Really, a lid for this inkpot, why?

Sumitsubo don’t come with a lid if you buy them. However if you plan to make your own sumitsubo (note the hint) make a lid as well while you are at it. One of the key things to work neatly and accurately is keeping your inkwell clean. There is plenty of dust traveling through the air in a carpenters shop that loves to settle among your sumi and then in turn sticks to your sumisashi. A lid will prevent this but it will also keep it from drying out during the dry season. During sumitsuke (layout) it is your main tool and you get accustomed to keep the right amount of water and ink in there. Make it too wet and things will be a mess but in general you should be adding more water than ink.

Wrap the silk wadding into a piece of cloth this helps to prevent fine strings of it getting stuck onto your sumisashi. I use a piece of old silk underwear that was in the rag bag at the workshop. I am afraid it used to belong to my boss to keep him warm during the winter. Why am I writing about my boss’s underwear?

Like many good things in life it takes some time and practice to become proficient in it. If you don’t want to bother investing some of your time and effort that is just fine too, you can stick with whatever works for you but you might be missing out on a very practical method. You have learned to eat properly with knife and fork so I am sure you can manage to learn laying out with ink. It’s a matter of good habits and muscle memory and the sumisashi will become an extension of your hand.

linedrawing toryo

Here is another provocative statement.

Laying out with a sumisashi and ink is the superior method for timber framing layout.

There you have it, I said it. Maybe you are a furniture maker and believe that a bamboopen is going to be annoying as hell. In that case try a Pilot hi-tec pen. These things are great I was sold from the first moment I tried one. A carpenter and friend of mine Mike Laine gave me one while we were building a house in Nicasio CA. It is a superfine gel ink balpoint pen and brings together the best of both worlds. You have the advantage of ink but don’t have to carry a sumitsubo around to supply yourself with fuel. You can’t drop them on their tip, it ruins them so I always have at least one spare one in my toolbox. The thinnest are 0.3mm so if you are in need for a finer line you need to stick with a sumisashi instead. They come in many different colors which is often handy but only the black ones don’t run out when your marks get wet.

Plot hi-tec pen

Tricks of the Trade

When accuracy is an utmost must the ink line can’t be too wet. It will splatter or mark a thick line (see the picture above with the layed out mortices). Take a small piece of sponge and fit it into your ink-container just in front of the hole where the line leaves the well. You will note that it helps too keep just enough ink on the line. The picture below shows a clear and thin line about 0.2mm wide, accuracy guaranteed.

snapped line

Every morning after brushing your teeth clean your bamboo pen and make sure it is sharp and has no dust on it’s edge. If the edge isn’t sharp you just grind it on your #4000 stone take of the burr and it is as good as new.

So in order of preference I choose sumisashi, hi-tec pen and a HB pencil. Knives take a seperate place since they remain indispensable in many occasions.

I was planning to write a post on how to make your own sumisashi but then I found this film instead. Here is a link to some nice footage about how to make a sumisashi or bamboo pen. I really enjoy these little films, they make me want to go straight back to work instead of sitting behind this computer screen.

Pamflets with instructions for laying out with ink have been printed and are being dispersed as we speak. They will be dropped out of airplanes over the western world over the course of the next week. Get your hands on a couple of them and send them to your fellow carpenters if for some reason they have missed this propaganda.



Tiny Structure

Almost a year ago I had a conversation with a client (friend is a better word) about a small structure I could build for him. He envisioned a small Japanese style frame, nothing fancy but with the characteristic proportions, high quality joinery and finished with a hand plane. After the initial conversation we shelved the idea concluding that such a project would be beyond the available budget. Nonetheless we kept on dreaming and said that one day we would build this nice little shed we had in mind. Instead we were going to build a cheap, quick and dirty carport-sized small timber frame with whatever wood we could find to accommodate his needs. Well, things turned out quite differently…

A short while later I encountered a bunch of pretty nice timber. Thirty years ago someone bought a pile of perfectly clear super fine grained Oregon Pine, some of it he used but about 3m³ of it had been stored in his attic cleanly stacked waiting for me to find it. Together we bought the lot, some of the lumber became mine but most of it was reserved for the little shed we where still thinking about. Amazingly just a short while later the same thing happened. More fine Oregon Pine that had been stacked in a pile for  twenty years was found so again we acquired more wood. Historically homebuilders bought timber long before they were able to build themselves their house. It makes a lot of sense when you think about it.

Forget about risking your savings on the stock market. Buy some trees, have them resawn by the carpenter who will build you your house. Stack the wood carefully and allow it to air dry for at least five years and you have just earned more money than you could make on any savings account.

lumber stack

Please keep in mind that for us living in Europe this quality of lumber is extremely rare. This stuff doesn’t grow here anymore, we have been extremely efficient in destroying our forests and making sure that the market is flooded with cheap, fast-grown, low quality wood. So you can imagine when I was working in California and one of my colleagues complained about a micro knot in an otherwise clear stick of wood my eyes rolled and I walked away without making a comment.

fine grained oregon pine

Some months later I was designing the quick and dirty timberframe we had set our minds to. I found it difficult to come up with a drawing for a cheap structure, one that would both be visually pleasing and well built. I tried really hard but couldn’t stop myself from thinking that instead of a cheap knock-off we could draw an interesting design for which we already had nice wood.

After making a detailed cost estimate I figured that it could all work out if I could just find some cheap labour to help me for a week. So I asked my friend/client if he could come and help me build his little building. We had worked together before so I felt confident that his help would be useful and because of his interest in this type of work he would be able to learn something at the same time. He would invest some of his time to work on his own project and therefore I could lower the overall price. Suddenly the project that was out of the budget fell into the budget.

Since we were now building a high quality structure another aspect became important. The structure had to be movable because it will eventually be relocated. This aspect affected the choice of joinery and how it was to be executed. Joints should never be loose but keeping in mind we want to take this building apart some day to relocate it they shouldn’t be overly tight either. The fit needs to be just right and the joints made so that they can be taken apart without damaging them.

cad tiny structure

I came up with this simple asymmetric design loosely inspired on a machiai. These are small shelters often found in Japanese gardens. Guests can wait there until the host is ready to receive them. They often overlook a specific type of scenery which creates a certain atmosphere before they enter the tearoom.

This structure is not intended as a waiting shelter for guests instead it’s function is not yet fully determined and the design and proportions are largely dictated by the available materials.

Eventually I hope to place the posts on natural round river rocks. Put a nice roof on top of it, cedar shingles and copper perhaps. Add roof trim pieces like komai and hirogomai but all this will have to wait  for now.

Stay tuned to witness the building process.