Japanese Inspired Inro Box
Tuesday 02 November 2010
Inro boxes were worn by the Japanese hundreds of years ago as pockets had not been invented, here Mark Sanger creates one from an ash blank
The inspiration for this project comes from the Japanese inro box. These boxes were worn by the Japanese hundreds of years ago as pockets had not been invented or used within the traditional dress. By tucking the leather cord and toggle under the belt of the kimono, the boxes were used to carry small items such as identity seals and medicines. Later, the inro box became a symbol of status. The scope for the design is almost limitless and by including different materials in place of the wooden toggle, beads and leather cord, the design and impact of the box can be greatly altered.
For the project I have chosen an ash (Fraxinus excelsior) end grain blank, the grain running parallel to the axis of the lathe spindle, 140 x 60 x 60mm (5 1/2 x 2 3/8 x 2 3/8in) cut in half lengthways through the middle.
The cut faces were then planed flat on a small bench planer and a planed piece of pine 10mm (3/8in) thick x 60mm (2 3/8in) x 140mm (5 1/2in) was sandwiched in between the ash. Again, with the grain running parallel to that of the ash.
Once the ash had been dimensioned and planed, a length of 240 grit abrasive was fixed to the table of my bandsaw with adhesive tape so the surfaces could be sanded smooth. All three pieces of wood were then sandwiched together using PVA glue. Newspaper was placed between each layer to enable the parts to be split apart once the project had been turned, with the pine section being removed and discarded. Doing this allows you to create an oval shaped box which is more unusual than the standard profile. You can modify or adapt the design as you see fit.
Tools used 19mm (3/4in) spindle roughing gouge, 12mm (1/2in) skew chisel, 6mm (1/4in) spindle gouge, 25mm (1in) round-nosed scraper, 6mm (1/4in) parting tool, 3mm (1/8in) parting tool and 6mm (1/4in) point tool
Accurately mark the centre position of the blank, place between centres and rough down to the round using a spindle roughing gouge. Using callipers, check the diameter in several places along the blank. Use a 6mm (1/4in) parting tool to clean up both faces of the blank. Produce a spigot at each end to suit your chuck jaws. Refine the spigot profile with a skew horizontally on the toolrest in trailing mode to suit a dovetail profile, if required
Using a 12mm (1/2in) skew chisel, refine the profile with planing cuts. Using a pencil, mark the sizes for the box and the lid section on the blank. The lid needs to be approximately one-third the length of the blank
Using a 6mm (1/4in) parting tool, part in centrally on this line to a depth of 5mm (3/16in). Start with the parting tool horizontally on the toolrest - this will give a sharp edge and will prevent lifting the wood fibres at the edge. Using the toe of a 12mm (1/2in) skew chisel, define the section/beads at the top and base of the blank. Also, cut a slight angle at the top and bottom face where the edges will meet to give a sight line at the join
Use a 3mm (1/8in) parting tool to part off the lid of the box. Leave 0.5mm of wood from the inside recess - this is used as a gauge when opening out the inside of the box to obtain a good fit for the lid. In this instance I have left the spigot on the lid to fit inside the box. But if you prefer, this can be left on the base section and the lid fitted onto this. Part the lid off leaving 10mm (3/8in) of material, then remove the lid using a fine saw blade
Tighten the lid of the box into the chuck jaws. Use a 6mm (1/4in) spindle gouge, rotated anticlockwise and cutting on the left side of the tool at around 10 o'clock of the cutting edge. Hollow out the interior, leaving the profile of the base interior concaved, as right-angled corners make it more difficult to remove small items from the box. Remove the material stopping short of the register material left when parting off
The next step is to use a round-nose scraper to refine the inside profile of the box you have created - I use a shearing cut
Finish the interior using abrasive from 120-400 grit. Gently finish the exterior diameter of the spigot that will fit into the base. Be careful to keep this parallel or it may be difficult to achieve a good fit later. Use suitable lung protection at this stage
Place the base into the chuck and hollow out using a 6mm (1/4in) spindle gouge, as before. Stop 1mm from the registration line/material. Using a 12mm (1/2in) skew chisel in a trailing mode, open out the interior diameter to achieve a tight fit with the lid. Continue to hollow out as before and finish with a round-nose scraper and abrasive. Only use fine abrasive within the recess area to achieve a good fit with the lid. Over sanding will loosen the fit too much
Turn a waste piece of sycamore (Acer pseudoplatanus) or other close grained wood down to fit into the jaws of your chuck. Turn the profile down with a skew chisel until the lid of the box can be jammed onto the waste wood. I generally take the waste wood down until I have a tight fit with the box and refine with 320 abrasive until a good fit is achieved. However, due to the material being in sections, achieve a light fit and bring up the tailcentre for added support. Too tight a fit on the jam chuck could split the pieces apart. Use a 6mm (1/4in) spindle gouge to refine the base of the box to produce a convex profile
Using a point tool or skew in trailing mode, produce a groove near to the outer edge of the lid. Note: here the waste material was removed prior to doing this, but this is not essential. Finish with abrasive down to 400 grit. Now repeat the process for the base of the box
Using a sharp knife, remove the waste wood on the ends of both the lid and the base. Finish with abrasive to blend in the profile. Place both parts onto a flat surface, and use a fine craft blade to carefully split down through the glue lines
Place 320 grit abrasive on a flat surface and gently remove any residue of glue and paper. Be careful not to alter the flat surface of the face you are sanding
Apply a fine surface of medium viscosity Cyanoacrylate glue and join the two halves of the box together. Hold them together with masking tape until fixed. Draw a central line through on the top of the lid and base. Mark two points on this line centrally - 5mm (3/16in) either side of the central point. Using a 2mm drill - depending upon the thickness of the cord you are using - produce two holes at the points though the lid and base
Using a small round-nosed engraving cutter in a rotary tool, produce a random texturing on the top of the lid and base. Sand back the textured areas with 400 grit abrasive and the other parts with acrylic sanding sealer. Once dry, spray the inside
Mask the main areas to be left natural. Take care to slightly overlap the areas to be left into the grooves of the defining lines. Run your fingernail around the inside of these to fix the tape and prevent overspray onto these areas. Coat with several fine coats of acrylic black spray. Repeat for the inside of the box. Once dry, remove the masking tape and coat with acrylic satin lacquer
Producing the toggle
Take a piece of waste beech (Fagus sylvatica) and cut down on the bandsaw to 15mm (9/16in) square x 110mm (4 1/4in) long. Mark half way along the blank and drill a central 3mm (1/8in) hole. Place between centres and using a 12mm (1/2in) skew chisel, produce the toggle profile so that the form is equal either side of the hole. Turn the ends down to a few millimetres. Finish the outside down to 400 grit by hand. Remove the toggle from the lathe and cut the waste material away using a sharp craft knife. Blend the ends with abrasive by hand down to 400 grit. Apply acrylic sanding sealer and allow to dry. Spray with acrylic black lacquer as before, allow to dry and seal with acrylic satin lacquer
Producing the beads
Rough down a waste piece of ash (Fraxinus excelsior) to approximately 15mm (9/16in) to fit into the jaws of the chuck. Here I am using button jaws. Clean up the front face using the toe of a 12mm (1/2in) skew chisel. Using a Jacobs chuck, drill a 3mm (1/8in) hole through the centre of the blank, deep enough so that you can produce two beads around 6mm (1/4in) thick
Using the 12mm (1/2in) skew chisel, convex the front face of the bead. Finish with 400 grit abrasive and use the toe of the skew to produce the back profile of the bead - to replicate the front. Once achieved, the bead can be sliced off with the skew. Finish the back of the bead by hand - if required - down to 400 grit. Repeat for the second bead, coat with acrylic sanding sealer and acrylic satin lacquer. Fold the cord in half and tie a knot at the folded end. Feed the cord ends through the first bead and up through the two holes in the base of the box. Feed the ends through the top of the box from the inside. Make sure the grain of both parts is aligned before doing this. Feed through the next bead, the toggle and tie the cord to join the ends. The Japanese inspired inro box is now complete