Ray Chest archive

Wednesday 30 September 2009

John bullar guide to exploiting the ray patterns of oak

Gallery

This simple little chest borrows a trick from the old Arts & Crafts makers, enabling the oak to show ray patterns on all four sides of the legs, giving a consistent figuring not normally possible with solid wood.

The whole cabinet, standing 600mm high by 800mm wide and 400mm deep with two drawers and an open shelf, is constructed from a single 4m-long board – a potential reject with extensive heart shakes retrieved from the middle of a stack of flat-sawn European oak (Quercus robur), photo 1.

The stability of this oak, with ray figuring across all the main surfaces, ensures that the simple carcass construction formed by butt joints reinforced with Domino loose tenons will not distort regardless of atmospheric changes. The construction is efficient and economical with a concession that the drawers are hand dovetailed for the sake of fineness.

Rayed legs

When you cut square-section stiles or legs for solid-wood furniture with ray patterning on one face they will unavoidably display flat-sawn contour markings with no rays on the adjacent faces. Although quite natural, the disjointed look of this figuring can jar in appearance.

Some of the old Arts & Crafts makers used a rather cunning tactic to get around this problem so they could show matching ray patterning on all four sides of a square post. The technique also allows you to build up larger sections from thinner boards without veneering or laminating which helps ensure good matching with the rest of the project.

Construction

Like the rest of this cabinet, the four corner stiles were made from 30mm rough-sawn board, planed and thicknessed down to 25mm. I set the tablesaw to 45° and cut a series of 16 prism shapes, each one trapezoidal in section – in other words a 45° triangle but without the right-angle corner, photos 2 & 3.

For ripping these saw cuts the fence needs to be securely clamped against the table to prevent the sharp edge of the oak working its way underneath.

Next I planed the angled face of each prism on the planer table and fine-tuned it using a long jointer hand plane. As well as being flat and smooth, the surfaces need to be angled at precisely 90° so as to glue them up into a square.

With PVA brushed on the back of each oak prism, photo 4, I bound them together with duct tape in sets of four, rayed faces outwards, then applied a large number of clamps alternating between each pair of faces to ensure even pressure and no distortion of the composite cuboids, photo 5. With the glue set I peeled off the tape and carefully hand-planed all 16 ray-figured faces.

Wide panels

You can witness from the uninterrupted width of quarter-sawn oak on some old furniture that in those times it was cut from massive-diameter tree trunks. Nowadays sustainable wood comes in relatively narrow boards and so, even for a small project like this, it needs to be edge jointed to make the cabinet top and shelf. You may also need to edge joint the side panels to ensure they are wide enough and consistently figured.

Oak ray figuring is fickle – plane a few more strokes off the face of a board and it completely changes in pattern.

This means that having matched up a pair of boards for edge jointing you need to avoid levelling the joints once they are glued up.

While biscuit jointing adds little to the strength of a thick edge joint, it does help maintain alignment so I fitted half a dozen biscuits down each edge of the carefully matched boards for jointing the top and shelf, photo 6

Frame joints

The side panels are simply butt-jointed against the stiles, photo 7. With such large long-grain surfaces and no alignment issues there would be little point in biscuiting them.

The drawer rails are constructed as a frame with glued joints to the front rail and dry-fitted joints to the back rail, photos 8-10. To save time on the invisible mortice & tenons holding this cabinet together I used a Domino jointer, which is in effect a hand-held morticer with loose tenons.

Finishing touch

Simple conventional ebony knobs, photo 15, with their close fine grain contrast well with oak, feel good to the touch and will not discolour. The finished cabinet, photo 16, was treated three times with Danish oil thinned with a dash of white spirit then brushed on and wiped off again before it set. This was applied to all surfaces except the drawer sides and runners.

Finally, all the surfaces including the drawer sides and runners were rubbed with beeswax paste and buffed to a sheen.

Making drawers

I made this cabinet on a fairly tight budget but even so decided to use hand-cut dovetails for the two drawers, photos 11-14. This provided good practice for an assistant who was helping me at the time as well as giving the drawers a finer appearance. In the conventional way, the drawer fronts are lap-dovetailed and the backs are through-dovetailed.

Once the glue was set the drawer frames were test fitted in the cabinet openings and lightly planed to provide a gliding rattle-free fit.

The length of the drawer sides is calculated to leave the back of the drawer 6mm short of the back of the cabinet. This gives more than adequate clearance for any slight shrinkage across the grain of the carcass without losing drawer space.

A pair of conventional drawer stops was glued and tacked with panel pins to the front rail beneath each drawer. This arrangement stops the drawer by its front and ensures that once the maker has selected the closed position of the drawer, it will not change with any subsequent wood movement.


Woodworkers Institute

Tagged In:

furniture , cabinet , oak , project , Chest , John Bullar , Patterns , Making

Buying Quartered Oak

Although buying oak that is sold as quarter sawn will assure you it has been cut that way, this does not necessarily mean that the growth rings will all be perpendicular to the faces, or that it will show extensive ray figuring.
The reason is simply due to the variability in the shape of trees and how well the sawyer can predict the line of the heart or pith. Sometimes commercial quarter-sawn oak can be disappointing unless you have an opportunity to inspect and reject each board.
For a larger project you might buy a good-quality stack of flat-sawn boards converted from the bole of a single oak tree so they are well matched. Inevitably, one or two boards from the middle of this stack will have been sawn right through the heart and so they will show extensive ray figuring across their faces the same as quarter sawn. This makes them unsuitable to match the rest of the large project so it is advantageous to set them aside for a small project like this one.
The secret of acquiring good wood is in the selection and this applies whether you buy ‘true quarter sawn’ or select it yourself from a run-of-the-mill stack.

Mortice Considerations

Use of a Domino jointer raises a couple of issues.
Firstly, the mortices here are aligned across the grain so they have a relatively small effective gluing area; however, the construction is so massive compared to its light duty that this is not a significant problem.
The second issue is one of alignment: when I previously compared the Domino to other jointers, see F&C140, I noted it has a tendency to wobble while cutting. This could easily upset the alignment so it is best to test out the joint on a representative piece of scrap first, then if necessary you can compensate for any inaccuracy in the machine’s setup.

Diagrams Click an image to enlarge