Cheri & Bernie, Chair Legs
This project is for a set of 6 matching chair legs in maple, sized and shaped as shown in this drawing. The project starts with a trip to the mill for the wood; a large timber of clear, hard maple was selected which measured 10' long x 8.5" wide x 3" thick. This is a kiln dried timber with ambient moisture content of 6.5%; it's quite large and heavy so it needs to be cut into manageable sections and allowed to adjust to different air and temperature conditions.
The timber is cut into 4 sections, each 30" long, here you can see one of those sections; these sections are left for 1-2 days to adjust. Once adjusted, the sections are each cut into 2 square blanks for the legs 3.1" x 3.1" x 30" and then cut to 26" lengths. Lastly, the edges of the blanks are cut off to make initial turning smoother and the blanks are now in an octagon shape and ready to turn.
Here you can see a blank mounted into the lathe and ready for turning into a round billet.
The blanks are very rough cut and have irregular sides so first they are turned into 3" round billets; this is done partly to make sure they are large enough for the largest part of the finished legs but also to check the wood for any cracks or imperfections. Sure enough, the 4th billet had a small pithy knot which was hidden and had to be removed. Thankfully it was small and shallow enough that the underlying wood looked good and after it was removed there was still plenty of remaining material for the diameter needed in that section of the leg.
The wood for all the billets looks great, clear of knots, nice color and quite straight grain. This photo shows the billet with the section that was cut away to remove the one knot encountered.
Here are all 6 billets rounded to 3" diameter and ready for shaping. After rounding, the billets are marked so they can be re-installed on the lathe exactly as they were when they were rounded.
The legs are being made in 3 primary sections; top, middle or twist section and bottom. Each section fits to the adjoining section by a heavy tenon or dowel which is turned as an extension to the primary sections; these sections will be glued together when the leg is assembled. Here are photos of one billet with the top and bottom of one leg rough-turned, the red lines mark where the tenons will be located. The top and bottom sections of one leg will come from each billet, the twist sections will be turned and carved separately.
Here you can see the top and bottom sections of the leg completed and these will serve as a pattern for the others.
The billets need to be cut into shorter sizes for turning the top and bottom sections. This is done to minimize the amount of whip or resonance that would occur in such a long billet with smaller diameters in the turnings; basically it allows sections to be turned quicker with nicer results. Here you can see how the billets are marked and partially cut on on the lathe; then they are moved to the band saw to complete the cuts.
Here you can see how the billet sections are cut on the band saw....
then the sections are turned on the lathe. There are two square sections in the legs (top and middle of the leg); because these sections are smaller than the adjoining round sections there's no way to really make them as part of a contiguous turning so they are made separately and added to the legs as they are assembled. The square sections are different sizes and they need to have finished surfaces when assembled into the leg so they will be prepared as longer square boards with the planer. Also, the leg sections with the twists need to be prepared for turning and here you can see the last remaining board section which will be cut for both the twist sections and the squares.
Here you can see the board being cut on the band saw for these sections....
... and here you can see the corners being cut off the blanks for the twist sections which is also done on the band saw.
Here you can see one of the boards for the square sections being planed to size. Once completed, they just need to be cut to length and bored to fit over the tenon sections of the leg and glued into place.
Here you can see the completed turnings for the top and bottom sections of the leg along with the boards for the square sections and the rough billets which will be turned for the twist sections of the legs.
Next up is turning and carving the twist sections. Here you can see the first being made into a pattern which will be used for the remaining 5. Before the twist is carved, the billets are turned to a semi-completed stage then the twist is marked and carved.
To make the twists, a grid is drawn onto the turning. First, a reference line is drawn lengthwise on the turning between the lathe centers. Then the length of the turning is divided into equal sections around it's circumference and the width of these sections determines how steep the pitch is for the twist. In this case, there are 9 sections (the lines at the very top and bottom of the turning aren't shown) each spaced 15/16" apart. This twist has 10 beads so the circumference has to be divided into 10 equal sections. Although this can be done mathematically, I've found it's easier and more accurate to wrap masking tape around the turning at the top and bottom edges and mark where it crosses the reference lines. The tape is then removed from the turning and laid flat, the distance between the marks for the reference line is measured and divided into 10 equal sections, in this case the spacing is 19/32" so the tape is marked at these intervals. The tape is then reapplied to the end of the turning, aligning it to the reference line and the 19/32" hash marks are transferred to the turning, this is done at the top and bottom of the turning. A line is drawn between the top and bottom hash marks and once completed the grid has been drawn on the turning.
Here you can see the reference line, the 15/16" spacing around the turning and the masking tape applied.
Here you can see grid drawn out on the turning.
A left hand twist is needed to match the pattern of the original legs which these new legs are modeled after. To create the twist pattern, a line is drawn freehand from the lower right to the upper left corner of each grid box; here you can see that's been done and the shape of the twist is now described on the turning.
A "V" shaped chisel is used to cut a groove along the twist lines, here you can see that's been done. This groove is basically a guide for a wood rasp which is used to cut and smooth the twist.
Here you can see the twist lines have been cut by a wood rasp.
Once the twist lines are cut, the top edge of the "V" grooves are rounded by sanding and this forms the smooth beads. Here you can see where a couple beads are being formed.
and here you can see the finished twist.
The legs have two small sections which are square, one at the top and one approximately center leg. Both of these square sections are different size and all of them need to be bored to accept the tenons on the other leg sections. Here you can see one of the top squares being bored and it is stop-bored (bored only partially through) to fit over the top turning. The square sections for mid-leg are bored through so they fit over the tenon on the bottom turning of the leg.
Here you can see all the square sections have been cut and bored.
Once the square sections are ready, the tenons on the top and bottom turnings are cut to length then the top and bottom of the twist turnings are bored to accept the tenons from the bottom and top turned sections. Here you can see a couple photos of a leg dry-assembled to test fit, alignment and sizes. It looks very good, the sections fit well together, alignment is good and it's ready to be glued into a single leg.
The legs still need sanding and trimming but they are beginning to look like the finished design.
Here you can see all the twist sections are carved; the ends will be removed and bored to accept the tenons from the top and bottom sections of the legs.
Once all the tenons have been cut to length and the twist sections are bored, the sections are glued into a single leg except for the square at the top of the leg. The flats on the top and mid square sections need to align so the top square section is glued separately, after the legs are glued into single pieces. Once that's done, the legs are complete except for a light final sanding.... and here you can see the finished set of legs.