Wednesday, November 2, 2011

New Project- Tripod table

After finishing the nightstand and toolbox, we have to complete 3 more projects to graduate- a table, a chair and a case piece.  I intend to do much more than that, but that is minimum.  The instructors want you to do a quicker project first, which usually means a table.  Many people do a demilune or a tilt top.  I didn't want to do those because I want to do a demilune with more decoration than they are willing to let me do right now and I don't like the way tilt tops look.  So, in talking to one of my instructors, he recommended I do a splayed leg table.  This, he thought, would be a good introduction to compound angles and thus would serve me well when it comes time to do the chair.  The hardest part of this project so far has definitely been drawing it.  It took a while to wrap my head around the angles and come up with proportions.
The overhang to the left looks way too dramatic in the drawing. 
The top looks like a UFO.  It is also to light to see well in this photo.

I tried a few different combinations of elements for the legs.

The project started with making an angle block.  This is just a wide block of wood that I can use to set the table saw to get consistant angles.  I set the table saw blade at the angle between the legs and the table top on my drawing using my bevel gauge.
Bevel gauge.  Good for setting and transferring angles.
I then ripped the block (cut it down its length) and then cross cut it (cut it across its width.)  This gave me the true angle between the top and the legs.
Angle block

I was able to use the same setting to cut the leg blanks.  Leg blanks are usually square, but we had to adjust the ones for this table because we wanted the stretchers to come into the leg at a 90 degree angle, but because there are only 3 legs they are at 60 degree angles to one another.  The solution was to make a pentagon shaped blank.  This allowed me to have 2 outside faces at 60 degrees to one another with the 2 inside faces being 90 degrees relative to those outside faces.  The 5th face is formed by cutting off the point formed by the two outside faces for purely aesthetic reasons.

Starting from a square blank and using the same table saw setting, I got a pentagon shaped leg blank.  The original corner from the square (top right) and the intersection of cut 1 and cut 2 are 90 degree angles where the rails will intersect the legs.
View of leg from above with rails intersecting from below and glue blocks glued on the outside.

After that, I turned the legs to the shapes I had drawn, leaving sections pentagon shaped for the stretchers.

Leg blank turning on the lathe with the main body of the leg turned down to a cylinder and the foot shaped. 
Close up of the foot and pommels (transition from blank shape to round).  You can also see the layout lines for the bead and coves.

close up of top pommel and layout of beads and thinnest part of the leg.

Finished leg ready for sanding.

Another view.

And another.

3 matching legs.

After the legs were done I cut the mortises in the pommels.  Then I cut the rails, using the angle block to set the miter fence on the table saw to the correct angle.  I then cut the tenons on the rails using the dado set on the table saw.  I used a follower block with the same angle cut it in so I could hold the angled end of the rail against the fence and push it safely across the blades.

Here's the legs with the top rails in.  You can see the mortises for the bottom rails on the pommels.
The bottom rails were a bit trickier to fit.  I cut them at the same time as the top rails, but they didn't fit.  After a few adjustments I got them there though.

Finally came the time to turn the top.  It is glued up from 3 pieces to form a 20 inch circle.  It was really exciting because it was the first time I have done an outboard turning.  That means the piece was too big to fit on the lathe normally, so the motor had to be slid down to the end so the top had room to spin.  The top is attached to the lathe by gluing a piece of plywood to it with a piece of paper in between, then screwing a face plate to the plywood.  The glue on the paper is strong enough to hold while it is turning, but the paper provides a clean break when you take the plywood off, leaving less clean up and reducing the risk of damaging your piece.

The 3 piece glue up for the top.  I had to put it on the lathe and turn it very slowly to mark a circle to bandsaw to.  After bandsawing the weight was more evenly distributed.

Mounted and ready to shape the outside to a perfect circle.  You can kind of see Gus in the background doing a more traditional inboard turning.

This thing was really moving when I turned the lathe on.  This is the second step- flattening the front.

Here I started to form the lip.  You have to form the outside before you remove the inside, because once the inside is gone, the outside can flex and you will not be able to remove material evenly.

From the side you can see I have also put a curve on the outside.  You can also see the very heavy cast iron tool rest for outboard turnings.

Close up of the edge.  From the outside there is a bead, a fillet and a cove.

Another shot of the primary shaping.

The whole thing is flat, except the nub in the middle.

I left the nub in the middle because when I tried to turn down to it, the knot ripped out.

So, I used my hand plane and card scrapper to flatten the middle after I took it off the lathe.  This way I was able to preserve most of the knot, the natural beauty of which I like.  I am still deciding wether to fill it with epoxy so it is completely flat or to just finish it the way it is.  My instructors differ on their opinions in this regard.


The finished top sitting on the the legs with both the top and bottom rails in.  I still need to cut the tops off the rails and legs after it is glued together, so it is flat across the top, so the top fits nicely.  Also, I am going to do some carving on the rails before I glue it up.

Here's a different view to illustrate what is funny about putting a round top on a tripod base.  When you look at it with two legs in line with one another, the overhang of the top seems absurdly long.

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