Making a Karibari Frame.

Have you ever heard of the "Batman Joint" in woodwork? Not until now... you see, for want of a better term, that is the name I called this joint used in the making of a Karibari frame.

Another interesting project! The paper conservators at the State Library of Western Australian wanted a karibari frame made up to particular specifications which they provided me. Mind you, the picture on paper of the corner did not make sense technically, so after a few goes at experimenting, interpreting the diagrams and comparing what I could find on the Internet, the Batman Joint was born as a solution.

The component on the joint which gave the Batman Joint its name.  

The material specified to be used was Western Red Cedar. It is light and stable, and resistant to mould and insect attack - but also very soft and cheesey to work. I was seeking to avoid any knots and keep the grain as straight as possible as I machined up the timber from the 3"x2" material that I bought to do the job. 

The completed Batman joint. If this is correct, then there must be a Japanese name for the joint...

So what is a karibari frame? Developed during the Ming Dynasty in China and later developed further by the Japanese, the karibari frame was used for flattening and drying scrolls and documents of paper and silk. The wooden frame has 7 - 9 layers of paper glued to one or each face. Like all things traditional Japanese, there appears to be an intricate and highly developed discipline, methodology and philosophy behind the construction and use of these papered frames. The karibari frame is favoured by paper conservators the world over for flattening paper documents and artworks.

Making the frame components.
This particular frame was to be 2.0m x 1.5m. The internal lattice is made up from 20mm x 20mm material, housed into the outer frame via tongue which fit into the groove which runs around the inside of the outer frame. The outer frame is rhomboid in cross-section, made from 30mm x 30mm material, which has been machined such that the inner face is 20mm wide, the outer face is 30mm wide, and the top and bottom faces both have the same angle from the outer face to the inner face.  The internal lattice joints are half lapped cross housing joints, alternating under/over. The corner joints of the outer frame are shown on the plan I was provided. It was this interesting and complex joint that became the Batman Joint after some experimentation. All joints in the outer frame are to be pegged with bamboo pins through that frame.  I did not assemble the frame, as this would happen at the lab in the Library, for conservation grade adhesives only are to be used. I offered to assist in the assembly and the pinning of the joints.

The cross-housing joints were cut on the radial arm saw after careful marking out.

A joint comes together for a test fit.

Ya can't argue with that!

The tongues were also cut on the radial arm saw.

Yep, a nice firm fit. An inner frame tongue housed in the groove of the outer frame. 

The rhomboid profile of the outer frame, before being grooved.

The outer frame's profile was achieved with careful machining using a couple of jigs in the thicknesser. The resulting profile was perfect. The full length groove was created via the table saw.

Inside shot of the Batman Joint, the outer frame corner joint. The long frame ends have horns.

Outside shot of the Batman Joint in the outer frames' corner.

The Batman joint was predominantly cut by hand, using my trusty Lie-Nielsen 15pt dovetail saw.Waste was removed with use of my drill press, scroll saw, and a couple of very sharp chisels. However, even with very sharp chisels, it was difficult to avoid crushing the wood fibres when chopping across the grain. Hence the use of the drill press to bore stopped holes down the scribed lines in a couple of places! Careful marking out was the key, as with all woodworking joinery.

Putting it all together.
Assembly day came around, when I had arranged to put it together in the lab at the State Library with the wonderful paper conservation staff. The components had not all been put together before, so it was good to get it done so easily on site. Assembling the inner lattice was a tricky job, like a big open basket weave, so we had to be careful not to break any of the cross-members while putting it together. I had a few spare sticks with me just in case, but fortunately did not have to use them.

The inner lattice assembled. Time to fit the outer frame.

With the inner lattice assembled successfully, all with nice tight fitting joints, it was time to put the external frame onto the lattice and put the Batman Joints together. the ends of the crossmembers had tongues on them ready to house into the grooves in the outer frame, and all these were nice snug fits too. These joints were glued with Wheat Starch glue. Conservation grade adhesive... no PVA or Titebond III here!

Applying the wheat starch glue to tongues and shoulders of the joints in the outer frame. 

The outer frame went together beautifully. The final thing to do was to insert the bamboo pins through the outer frame and into the ends of the lattice crossmembers.

That's a bamboo pin (more like a nail) fitted.  

I used bamboo skewers as the pins, pre-drilling with a 7/64th " drill bit and driving them in with a hammer, wiping a bit of that wheat starch glue onto the pins before driving them in. Any protruding length was cleaned off flush with my trusty block plane. The final job to do was to use the block plane to trim flush any of the cross halving joints in the lattice which were not perfectly flush.

Job done! the completed Karibari frame.  

While my part in the building of the library's karibari frame was over, there is still much to do by the library's conservation staff. They are waiting for the special paper and other materials to arrive from Japan. Nine layers of the special paper will be glued over the entire frame, on both sides, following a strict methodology. I look forward to seeing the end result.

This project has been a very interesting one. Thanks to the very nice conservation staff at the WA State Library for asking me to make the wooden frame up for them. It's been fascinating!

Farewell to the Batman Joint!