I had a small commission recently for 6 3-legged stools, 10" (25cm) diameter, so I sourced some K/D beech from my local sawmills, who fed the board through their thicknesser for me - my thicknesser is only 8" (20cm) capacity. Then a thought struck me; as both surfaces were smooth and clean, why waste time turning them? So I made a very simple jig to enable the rim to be turned and the edges radiussed; it's just a hefty piece of timber, turned to 9" (17.5cm), with a chucking recess on the back of it and three holes drilled through it to enable the stool-top to be screwed to the jig. Once the edges are turned and radiussed, the top is taken off the jig and then 3 holes are drilled into the underside of it, to accept the tenons on the tops of the legs. I carry out this operation using a pillar drill with the work table tilted at 12degrees, using 1" (2.5cm) forstner bit for the holes. The centres don't need to be marked out, as I use an 'L' shaped piece of 3/4" (2cm) MDF cramped onto the drill-table in such a way that the workpiece sits exactly as I want it under the drill's centre-line. I just line the screw-hole up a 1/4" (0.6cm) to the left of the drill-bit's spur, and drill the hole to a depth pre-set on the pillar-drill's depth stop. The result is a finished stoop-top with no visible chucking points.
I timed myself turning a batch of tops today; each one took just 5 minutes to turn, including mounting onto and removing from the lathe. Drilling the holes, once the pillar drill was set up, took a further minute!
This is the jig prior to fixing a blank to it. I've used 3 screws, each 12gauge and 3" (7.5cm) long
I marked my jig with screw centres for both 10" and 9" (20cm and 17.5cm) diameter tops and also marked 24 equal positions....you never know what else it might get used for!
C&C always welcome....Les