The next step is for the arms to be carved out on the table saw. Building this nifty jig allows you to setup things very easily and pass the boards across the blade at the correct angle and keep your fingers out of harms way.
This picture shows the table saw setup with the guide, the jig and one of the arm blanks mounted in the jig. I have permanently marked my table saw for where the guide board goes as well as the number of turns to take on the blade height handle.
The process here is to start with the blade at zero depth and then come up 1/4 turn after each pass. The arm blanks passes over the blade at the correct angle and we slowly carve out the cup in the arm. Each arm takes 12 passes over the blade. The jig just flips over from right arm to left arm so the whole process is very easy and quick.
Here are the arms after the carving on the table saw. Notice that the process leaves a lot of ridge marks in the cupped out areas. It takes a bit of sanding and careful attention to detail to ensure you get all of those ridges sanded out.
After marking the arms with the template from the plans they get cut out on the band saw. From here I will use the ROS with 60 grit to get them very close to final shape. A few passes over the router table with some round-over bits will see them to their final profile.
Also this week the back brace strips are cut and started glueup. Eight back braces are made even though only seven go into the chair. This gives you an extra one in case one gets messed up during fabrication. I also hang on to all the extra back braces just in case a customer ever has a broken one I have one on hand that will match the chair pretty well. It takes 4 days to glue up all the back braces, they get glued up in pairs. Very similar to the rocker jig, just a form with angle aluminum for keeping the strips aligned and lots of clamps.
Hal recommends the use of Ash for the center two strips of each back brace, claiming ash is stronger and more flexible. I have made braces using the ash, braces that were 100% walnut, 100% cherry, 100% maple, half walnut/half maple and have not found any difference in the flexibility and feel of the back brace. Nor have I ever had one reported broken or broken one myself. Maybe one day I will make up some test laminations and do some stress tests, will be an interesting experiment.
Thus ends Week 2. Next up is leg shaping, both back and front.
-- Rich, WNY, www.nyrockingchairs.com