Here's an interesting project I'm enjoying. A client needed a table to showcase some brochures and artwork for sale purposes. They furnished the design of what they wanted, but subject to change as needs or applications may warrant. The table is a octagon and needs to be a total outside top dimension of 44", and 38" tall so the viewer can look at its content without bending over. The top will have a plexiglass insert as opposed to regular glass, due to the weight and handling when changing the contents.
The table is to be Mahogany so this means all the legs have to be made special, due to the length and material used. A project like this is best done with a good layout with actual sizes pieces used so as to avoid costly errors as well as a good visual to the overall project and its construction methods as far as joints, and making any jigs needed for duplication, as this table appears to be the first of a possible several that may need to be done.
First was to cut a sheet of birch in half. I'll end up using the sheet as the bottom of the display box later and a 4' size will give me plenty of room for any clamping. The 3/4" will also stay pretty flat which will be important as I put the temporary pieces together for measurements as I go along. I used the festool saw system to cut the sheet and the nice part about the system guide is that it has rubber strips on the back side to avoid sliding, and makes an excellent straight edge to get a good starting point in my layout. There will also be a bench, and you can see the customer furnished design on the table. The layout is pretty easy knowing that 22.5 degrees is the angle. Knowing the outside measurements, its just a matter of cutting a couple of pieces and spacing them out to the outer dimension, starting at the straight edge. Once one piece is sized, then its just a matter of cutting all 8 pieces the same size. The best method is to use a stop block on the fence because if each is measured then cut, there will be variations and with this design everything has to be on the money for the joints to be perfect.
Once the layout is complete, I can determine where everything is going, and also the size of the parts needed to stay in perspective with the drawing. Looks like a 3.5" turning will workout, so I glued up some poplar to make up a leg for approval. I made a template and set up my Vega for duplication. What a pleasure it is to work with this duplicator
Prior to any turning, I locate the centers and bore a shallow hole about 3/8" with a fostner bit. This is a safe way to secure the lathe centers from traveling and possible injury resulting from a piece flying out when turning something this large.
A large piece like this should be started on a slow speed and once the bulk is removed, then faster speeds can be used for better results.
Sanded and ready. Poplar sure turns nice for a prototype. I tried some scrap yellow pine first, but didn't care for the results.
The apron will be morticed in so the best method was to cut a 22.5 degree shim under the turning and give it a trial cut.
That was the easy part ;-)
The mortice in the taper for a stretcher is another story, so a jig has to be made to keep the angle in alignment with the center and apron. Once the turning is locked in I can be assured the same angle and location will be in alignment. The sad part is that the 3.5" top square part won't fit under the mortice chisel in the cradle, so I'll have to do the top part separately
Having 2 turnings done, now I can make up the stretcher and try it for size. Not as easy as it may appear due to the taper and cylindrical design of the turning. The angle has to be cut, then over to the spindle sander to get the concave shape. I'm just using scrap at this point to experiment with to avoid wasting Mahogany.
Once its sized, and located I'll be ready to route a hole for a slip tenon.
Another pass on the spindle sander, and this ought to fit real tight, then I'll use a spiral cutter and make up a jig for the router table to make a mortice for the tenon
Now that I know pretty much where I'm headed, time to start whipping out the legs and first start is to clean up some 16/4 Mahogany.
I ran them through the planer for thickness, then over to the jointer to dress and edge for ripping.
Now the fun part......... turning 8 of these for that table
Now for the jigs. The Apron has to be attached at 22.5 degrees so it will need a mortice at that angle. To do tenons at this angle can be a problem but I made up a jig for the router table for a floating tenon. Its done by end boring the apron piece deep enough to compensate for the 22.5 degree angle cut.
Now the jig. Very simple and comprises of a pocket so there is no play, and start and stopping
place for the slot. I used a 1/4" bottom so the work piece wouldn't have the tendency of pulling down into the bit hole in the insert. I used a spiral bit and set the depth of cut for 1". Drop the piece in and pull or push depending on what type bit being used.
One more leg to go, and started fitting the apron parts
leg mortices done, and ready for the slip tenon
