Back to Building Furniture
The Chair – Building the Legs
Time to start the build, beginning with the legs. The following was completed today.
All the legs are identical and I took the measurements off this one.
The plan is the turn all the legs and add the mortices later. One option is to add the mortices first and then turn the legs. However that will not work. Not only is the Curly Jarrah hard and highly interlocked and, thus, likely to be brittle and chip out around the mortice, but all the legs are canted and the mortices are not square. The angles can only be decided later, when the stretchers are completed.
Here is the wood I have. That is sufficient for 4 legs, the 4 stretchers, and 2 arms. I have not cut the section for the backrest.
The section for the backrest will come from the 150 x 150 in the lower right corner (below). It is long enough to use for a leg, if I need to do so – but then I will not have wood for the backrest. My reasoning is that the legs must match, and I can always use a section of ordinary Jarrah for the backrest, if necessary, as long as the colour matches. Hopefully this will not be necessary – the legs are pretty straight forward.
Before the legs are turned I built a template for their profile. This was made out of 12mm (1/2”) MDF – in the USA I would imagine everyone using plywood. In Oz the only plywood available is for industrial use. It is really crappy, full of voids and unpleasant to use. Consequently I use MDF for templates, mostly 3mm (1/8”) thick.
So who says you cannot plane MDF
Below is the template and the leg from which it came.
My Christmas present to myself was an EasyWood carbide-tipped roughing lathe chisel from Pop’s Shed in Brisbane. This is the most amazing lathe chisel. This is the “Full Size” version. I was unsure which of the sizes to purchase – there are two small versions and a larger, Professional, range. I was concerned that the Full Size would be too large. However it was just right. I was very happy to have the extra handle length for leverage when roughing out the Jarrah. You will note that the handle is different: it provides two grip choices – one for leverage and another choked up for detail work.
It has a four-sided carbide chip that is screwed to the end of a steel rod. When one edge dulls simply loosen the screw and turn the next face to the front. There is also a chip deflector – that windscreen – to … well … deflect chips. And it works fabulously – to such an extent that, other than glasses, I could forgo the usual face protection I wear when turning.
Now here is a jig I built that did not work.
I have a Jet mini lathe with an extension bed. It is fine for spindles, which I have turned before. My past experience in doing so made me wish for a longer chisel rest. Ideally one the length of the spindle.
I had this idea to use a length of steel pipe, and build brackets for it at each end …
The problem was that the pipe still flexed, and the combination of this and the spindle flexing in the centre was a near disaster. I removed this rest and returned the wee Jet one. That worked pretty well even though it required frequent moving.
Above are the Jarrah shavings made by the carbide chip: short. The chisel acts more like a scraper than a skew chisel. Nevertheless it leaves an excellent finish. If you return to the first picture of the chisel you will see a test piece of the Jarrah. This only received a light sanding before a coat of Danish Oil. The finish is fantastic!
Below are the four cylinders turned for the legs. Note that the ends are left square. These will act as reference for working to square when the mortices are added.
Back to the lathe. The cylinders receive markings at approximately 25mm (1”) spacing with the thickness of the leg at that position.
Here are the turned legs with their depths of cut completed. The temptation is resisted to complete a leg before moving on. It makes for greater consistency to do just one task at a time.
Finally the waste was removed from between the depth cuts, and the legs faired with a sanding pad.
Four completed legs. The template is used to check the profile of each.
Here are the legs alongside the chair …
And a final picture of a leg alongside a leg …
The next step planned are the stretchers. Stay tuned.
Regards from Perth
January 1st 2014