Friday 27 November 2009
Dave Maunder manufactures these simple tables in pine
My partner asked me to make a pair of tables to match some existing pine drawers. The tables were to be 457 x 305 x 381mm high (18 x 12 x 15in), and would be primarily used for snacks whilst watching the television.
Construction of the tops was from planed boards biscuit jointed together. For the legs and rails I decided to use loose tenons, something I had never tried before, as I wanted to extend my range of skills.
The materials used were pine boards from my local timber yard. I checked the thickness of the narrower boards for uniformity with vernier calipers and used these as supplied for the tops.
The legs were made from nominal 75 x 50mm (3 x 2in) timber resawn length ways and then thicknessed to a square section.
Legs and rails
1. The timber for the legs was resawn on the tablesaw. With the sawn side side up, I thicknessed the legs to give four planed sides then rotated the timber and re-planed each side to achieve a square cross section.
2. Using a stop on the mitre saw, all the components were cut to length. I cut an extra one of each component in case of mistakes/machining errors later on. I then marked adjacent joints on all components.
3. I machined the mortises in the rails using a router. I used a homemade mortising jig, but two lengths of wide timber clamped each side of the component to support the router would suffice using the router's fence.
4. Once the mortises where completed, I then cut the loose tenons to length from 6mm (0.25in) thick stock, on the mitre saw - I used some oak that was in my offcuts bin.
5. After fitting the tenons into the rails, I mitred them with a tenon saw. A mitre saw would be too severe on such unsupported thin timber.
6. The leg mortises were cut using a chisel mortiser. Alternatively,
you could drill out most of the waste with a Forstner bit and clean up with mortise chisels.
Making the top
7. When laying out the boards for the top, alternate the end grain orientation to reduce the risk of cupping. Any edges not at right angles to the face should be trued up using a bearing guided router cutter set against a straightedge clamped to the workpiece.
8. Line up the boards for the top and mark the positions of the biscuit joints. Also draw two diagonal lines from the centre of one end to the far corners. This will ensure correct assembly of the boards at glue-up. With the boards laid on the bench, place the base of the biscuit jointer on the bench and lower the height setting fence until it just touches the face of the board. This will prevent the jointer from rocking and ensure uniform biscuit joint heights. On thicker boards, place a plywood packer under the base of the biscuit jointer and adjust the cutting height as necessary.
9. The biscuit joints don't have to be exactly on the centreline of the board edge but they do need to be at a consistent depth from the face.
10. Assemble the boards dry with biscuits in place to ensure that they will pull together easily when glued up. Then glue up the top with two sash cramps underneath and one cramp inverted on top to keep the boards flat until the glue has set.
11. Good glue penetration will give strong joints with little evidence of glue lines when using polyurethane glue. With the boards alternated to reduce cupping, there is no uniform grain direction. So to reduce the risk of tearout use a block plane at 45° to remove the excess glue and level the boards. A sharp blade is needed for this. Note the wafer thin shavings.
12. Using a belt sander, sand the top to 120grit. With any machine sanding there is always a risk of over sanding the edges, so complete this procedure before routing the profile on the edges. The final sanding should be done by hand down to 320grit and 0000 grade steel wool. The top was then trimmed down to near finished size on the tablesaw before planing the finished edge prior to profiling.
13. Glue the legs up as two pairs, checking for square before the glue sets.
14. Now glue the two sets of legs together with the side rails, checking for square and clamp up. Then glue in mounting blocks for the top.
15. I then machined screw slots with a 4mm router cutter to allow for expansion/contraction of the top.
16. With any project it is always possible to see a better or easier method of construction after completion. As the top of one table was cut to size, a knot broke away from what was to become a finished edge. I did not want to cut down the top and glue in another board so I came up with the idea of using a piece of dowel to replace the knot.
Using a 9mm Forstner bit, I drilled out the side of the top about half way through and glued in a piece of 9mm dowel. The dowel was then cut flush using a double edged pull saw which has the teeth set to one side only. This helps prevent damage to the surface of the top.
17. The edges of the top were profiled with a round over cutter. On reflection, I should have drilled through the edge of the top to make a more convincing dummy knot, but I was able to disguise it by colouring the dowel and surrounding area. Lastly, I applied two coats of Danish oil and a coat of paste wax.