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By embarking on this realization, Jean-Marc Folmer had set himself the goal of a quality of assemblies as perfect as possible. A project that requires obvious skills in woodworking, if only for the composition of the board and its elliptical shape... Take up the challenge!

An oval table with extensions

Level: confirmed
Realization: 150 to 200 hours
Equipment: combined wood, band saw, ripper
See the plan of this realization (in pdf): An oval table with extensions: the plan

A solid oak table

In addition to its large paneled tray, this solid oak table is distinguished by its four turned legs and low cross fretwork. Many grinding operations (on curved parts) are "on the tree", which requires a solid control of the machine. In addition to the wood combination, you must have a band saw and a router.
Including panels, the tray required the drawing of a scale scale and a cutting template. Its shape is not a true ellipse but a composition of arcs of two different radii. Each half-tray consists of two panels èvered between a bent mattress, an upright and a median cross. These panels are made of blades of 100 x 28 mm section, placed at 45° to the axis of the plate and glued flat attached.
The pads are in five parts. Shims of thickness are glued under the two half-plates to screw the slides. The extensions, built on the same principle, consist of two large sleepers, three small (including a central) and two panels. Their connection with the half-trays is provided by nine pigeons.
Between the feet, turned by a professional, the low cross fretwork and the spacer receive a quarter-round molding to "squares". The table belt, also molded, has three ties including a central. They are notched to receive the tray supports, held in place by a plate to prevent tilting thereof.
All the structural elements are assembled by tenons and mortises glued and pegged. Four ball rails with angles are screwed behind the belt rails. Their presence facilitates opening, but requires two grooves at the top of the feet and a notch at the ends of the central cross. Last element of hardware: knee mechanisms that lock the elements of the tray.

The base

Debit and correct all parts according to the debit card. Once the feet turned (by yourself or a professional), dig three mortises: one for the low cross and two for the corresponding belt elements. Be sure to mortise the two low crosspieces still rough, before singing them with a band saw. Then equalize them to the sanding drum mounted on the router. Also, slit the side members at half length.
Cut (and round) the tenons of the belt elements, those of the central and low cross members, and the spacer. In the three top rails, cut out the notches for the tray supports precisely. Raise the dimensions of the slides to spin on the top of the feet their grooves of passage. For the same reason, hook the central cross member at each end and then make the recess of the holding plate in its upper edge.
Machining done, start by assembling the spacer to the lower rails. After drying, mill the quarter-round round molding on the assembly thus formed. Also mold the outer low edge of the belt elements. Then proceed to a blank mounting of the base and present the slides. If their last fixing hole is in the feet, drill them to gain access to the screw.
After a final check, finally assemble the base and go to press. When the glue has dried, pin the junctions (in one or two points depending on the location) at the feet and low cross. At this point, you can prepare the shelf supports by bevelling one end and slitting them 10 mm apart to 640 mm long. It remains to drill the housing screws fixing the tray.

The skeleton of the plateau

Make the eight panels by assembling the flat boards singing. Based on the drawing drawn at scale 1 (see detachable drawing) to position at 45° those of the four panels which must be rounded (half-trays). Paste and go to press. While the glue dries, saw miter the ten segments (gross wrought) constituting the mattress while respecting the angles (15° or 22,5°) indicated in the plan. With this done, hold at each end the segments A and C, the six small crosspieces F of the extensions and the two middle crosspieces E of the half-plates.
Slaughter the B segments of the mattress at the end and, at the ends and at mid-length, the inner edge of the six large D / D 'crosspieces. In the opposite direction, dig the pigeon lodges to secure the half-trays with the extensions. Finally, in the A-segments, machine the mortise for the assembly of the median crosspiece: it is not centered in the thickness of the edge but is 12 mm from the facing. After a blank mounting for verification, assemble the two pads.
From the sketch, make a semi-elliptical 15 mm plywood template. It will allow you, in several stages, to calibrate the rounding of the sketches (externally then internally) and that of the panels. As a first step, mark the outline of the mat to outline the outer edge of the band saw. Then screw it successively on each of them, assembled to its cross D, and use it as a guide to refine the roundness to the top.
Dismantle the template to draw a new half-ellipse set back 120 mm from the edge. Cut the chute carefully with a band saw. After sanding, make marks on the new template to always use it in the same direction: you will fix it on the underside of the pads and panels so that their contours coincide precisely.
Remove the middle rails to calibrate the inner edge of the mattress pads. The surcharge is sufficient here to screw the template. With the reamer equipped with a 10 mm straight cutter and a 30 mm copy socket, cut a 15 mm deep groove in each underlay, following the outline of the template. Guiding you on the sharp edge of the groove, then eliminate the scrap with the bandsaw. Finish calibrating to the router.
To finish, dig a 16 x 17 mm groove, 12 mm from the facing face, on the inside edge of the mattress. Similarly groove, on one or two songs according to the pieces, the different crosspieces of the trays and extensions. Note: the grooves of the D sleepers are stopped at the mortises.

The signs

Using the sketch, draw the final outline of the panels composing the half-trays. Cut out their straight edges with a circular saw and cut out there curve to the ribbon. Also, size the panels of the extensions, before folding them all over their periphery and thus realize their tongue of recess. You can now assemble the extensions by letting them dry in the press.
Attach the template, set back 35 mm from the outside edge, under the two panels of the first half-pan: use the crossbeam to adjust their spacing. Then calibrate to the router with an advanced bezel 35 mm from the tool. Do the same for the other half-board.
Once the panels have been calibrated, insert the middle crossbeam by aligning the three pieces at the back (extension side), then reassemble the template with wedges to compensate for differences in thickness. At the same time, machine the curved rabbet of the half-plate and the second stud of the median cross-bar, the flattening of which will follow the same curve. For this operation, the bezel is advanced by 15 mm relative to the tool. This setting is also used to level the other side of the post.
Before gluing, assemble each half-board blank to make a tightening test: you may need to make specific martyrs wedges. Once dry, present the shims underneath (allowing screwing of the slides) to trace the curved end. Cut them with a bandsaw, even the cut and fix them simply by gluing.
As before, anchor the assemblies of the trays and paste in place (in the same direction) the pigeons to secure them. These are cut into a board whose edges have been rounded with a rasp and sandpaper. Gather trays and extensions to sand them and similarly round the ripper, their peripheral edges.

Assembly and finishing

Screw the runners flush with the surface of the base. Also secure the bracket and then engage the tray brackets in their slots. Before screwing the half-plates to the slides and supports, make sure that their median cross is parallel to them. Otherwise, you will have problems of joining.
Check the sliding and positioning of the extensions, and always install the different locking mechanisms in the same way. All combinations, with or without extensions, must be lockable.
For finishing, remove trays and hardware. Sand any remaining imperfections. The whole is here tinted with the gun, before receiving a first layer of varnish, a patina to be shaded then the second layer of varnish.
Wait until the varnish has completely dried before screwing the hardware store and putting the tray back!

Turn and mortise parts

Turn and mortise parts

Made up of four pieces laminated, the feet were turned to order by professional. They are mortised on one or both sides to receive the belt elements and the low crosspieces.

Assemble to the router

Assemble to the router

The molding adorning the upper edge of the bottom rails and the spacer is executed after assembly to the router. The leveling of the tenons of the sleepers is reduced to the strict minimum.

Assemble the base

Assemble the base

Clamps would be very useful to assemble the base. If you only have large pump models, chock them in the middle to compensate for their lack of rigidity.

Round the tabs and groove the sleepers

Round the tabs and groove the sleepers

The grooving of the large sleepers must be stopped at the end of the pass just before the mortises. This will require rounding the end of the tabs of the panels so that they lift properly.

Machine the recess groove

Machine the recess groove

After calibration of the outer and inner edges of the mattress, the recess groove of the panels is machined to the top. Tree work requires good control of this machine.

Assemble the half-trays

Assemble the half-trays

The panels of the half-trays consist of boards 100 mm wide, assembled flat vocals by directing the wire at 45°. Several tight joints are needed to keep them in press.

To clean and calibrate the curve of the panels

To clean and calibrate the curve of the panels

The curved edge of the panels is first cut with a circular saw, then calibrated with the template used to machine the inner edge of the mattress. The curves will be strictly identical.

Feuillurer the panels

Feuillurer the panels

The template is still used, enhanced by wedges, to flush the panels to the router with a guide bezel. The tenon of the median cross, side mattress, is machined at the same time.

Maintain the clamps

Maintain the clamps

To properly distribute the pressure when clamping the half-panels, it is necessary to make specific martyrs wedges that keep the clamps at the desired angle.

Sand the trays

Sand the trays

The sanding of the trays, carried out with the eccentric sander, is not intended to make up for major defects. Be precise by adjusting the router to groove the mattress and flip the trays.

Assemble the extensions

Assemble the extensions

Assembling the extensions is not a problem. Given the thickness of the parts, the risk of bending when tightening is non-existent and only squareness remains to be controlled. Do not forget the martyrs holds.

Place the ankles

Place the ankles

The ankle section is 9 x 9 mm at one end, 7 x 7 mm at the other. The hole is 8 mm. They are not essential but accentuate the traditional aspect of the work.

Round the edges of the tray elements

Round the edges of the tray elements

The elements of the tray are assembled to round their edges. The 20 mm quarter-round cutters are 12 or 12.7 mm shanks; reduce the radius of curvature if your router does not accept them.

Ball rails

Ball rails

The angle of the ball rails should just be flush with the surface of the feet and the belt. The passage in the feet is machined to the router, or eventually to the router after assembly.

Adjust and mount slides and brackets

Adjust and mount slides and brackets

Examine the assembly of the slides from the beginning of the site. If, as here, a fixing screw is fixed in the foot, it is difficult to pierce the passage of the screwdriver after assembly. Closed as open, slides and shelf supports must remain on the same plane, which assumes a precise fit. The supports are thinned at one end to pass under the plate.

Go to blank

Go to blank

A blank mount makes the final checks possible. Try all the combinations of the trays: without extensions, with the two and each of them as it is the case.

Finishes of half-trays

Finishes of half-trays

For finishing, the half-trays are removed and the hardware dismounted. Spread the panels on two cleats to limit handling and expectations during drying.

Spring closure

Spring closure

This type of spring closure allows effective locking. Place them in the same location under the different trays to be able to use them in all configurations.


Video Instruction: Making the Johnson Table