Sunday 9 June 2013

A Tale of Two Tables: 5. It's Got Legs

A solid base is key to the functionality of any table. A lovely top will be ruined by an uneven, twisted base or one with legs in the wrong place. For our small table we went for four legs in a square, 20" apart leaving an 8" overhang outside the frame. Traditionally the cross pieces would be mortice and tenon joined into the legs. This is a fiddly process but if done right is immensely strong. We do not poses the skill of years of practice at mortice and tenon joints so ours would neither be accurate nor straight! I am very grateful however for the research of John D Wagner who showed that biscuit joints can be stronger than mortice and tenon or other methods. Although the research was limited it provides some armour to fight those traditionalists who think biscuits are no use in structural elements.

Enough design - onto the doing. As we were biscuit jointing all we needed were square legs and straight ends to the cross pieces. As the legs were already square that left us with cutting the cross pieces to length in a square manner. This was another job for the router to try and get the ends square and allow millimetre precision. If you had a decent table saw you may be able to use it instead but there are only a few power tools in our garage!

Having cut the ends we then used a curved bit for the router to round the underside of the bar. The biscuit jointer then came out again to put the slot in for the biscuits. We aligned this slightly off centre to ensure the biscuit didn't show at the bottom (I am sure this probably sacrifices a little strength but it only came out the top a fraction).

With the frame cut, rounded and slotted the attention shifted to the legs. We needed to choose the outside faces, check for any cracks or deformities where the biscuits would need to sit and mark which end to remove the waste from (in a straight manner). Lacking a power saw this was a time for hand tools. The router would not have the depth to cut this one. I used a tenon saw for better control of the cut, the 2 1/2" legs just fitting on the blade. 

To ensure the legs were all absolutely even we strapped them all together with a large quantity of elastic bands (many of which we snapped in the process) and sanded the ends flush. Two slots per leg later we were ready to sand all the parts of the frame and glue it.

To assemble we glued the legs into pairs, let that dry enough to hold itself, and then brought the whole frame together. A webbing clamp held it all together and we used the sash clamp on the diagonal to apply very slight pressure to pull it all square.