| Three-Legged Stool: Legs and Assembly |
| Three-Legged Stool: Legs and Assembly |
From "Trade School" episode DTRS-102 |
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Here, woodworking student Tyler Chartier crafts the legs and then begins the assembly of a solid cherry, three-legged stool ....
Basic Tools:Jointer Planer Plunge router Jigs Miter Saw Band saw Belt sander Bow saw Coping saw Japanese saw Block plane Chisels Drill Press Spoke Shave Heat Gun Steel Mallet Rubber Mallet Wood Glue Bit Brace Quick Action Clamps With the seat portion complete, Tyler crafts the legs and stretchers of the chair. First he creates tenons for each leg. He makes sure to align each leg stock plumb in the drill press. Then he bores the leg tenons with a plug-cutting bit (figure A). He carefully removes the wood surrounding the tenon with a chisel.
Tyler shapes the legs and connecting stretchers with an adjustable spoke shave (figure B). After securing each piece of stock in the table vise, he removes wood aggressively with a wide depth of cut. As he nears the desired shape, he sets the spoke shave at a narrow depth for finer shaping. He shapes the back leg and stretcher later in the process.
Next Tyler inserts the legs into the seat board mortises and marks the front stretcher to the proper length. (figure C) The front stretcher joins the front two legs together near the bottom of the chair.
After shaping the stretchers, Tyler directs a heat gun onto the ends to ensure the stretchers fit tightly into the legs (figure D). The heat causes the ends to shrink by removing moisture from the wood. Later, the wood regains its moisture and expands creating a snug fit.
Tyler utilizes a wedge to strengthen each mortise and tenon joint. To insert the wedges, he first drills relief holes through the tenons of all the legs and stretchers. (figure E)
These holes prevent the wood from splitting the kerf when inserting a wedge. (A kerf is the space created to accept a wedge). Tyler creates the kerfs on the band saw, cutting until he reaches the relief hole. (figure F) He also uses the band saw to cut the various wedges for the chair. He tests each wedge to each corresponding kerf before glue up. (figure G)
Tyler begins the assembling the legs to the seat with a liberal coating of wood glue inside the mortise holes of the seat and tenon ends of the legs. (figure H) Then he inserts the leg tenons into the seat. He also applies glue to the wedges for the front two legs. Then, he gently taps the wedges into the kerfs with a steel hammer. To create a solid fit, Tyler taps the seat onto the legs with a rubber mallet. This action actually breaks the seat board in half! He remedies the mistake with a quick glue-up and a series of clamps. (figure I)
With the front legs glued-up, Tyler joins the back leg to the front legs with another stretcher. He inserts the back leg tenon into the rear seat mortise and uses a spring clamp to align the stretcher with the leg. Using the clamped stretcher as a sightline, Tyler drills into the back leg with a bit brace at a level equal to the front stretcher height. He drills until the bit barely pokes through the other side. (figure J) He stops here to prevent the wood from tearing. He still needs to shape the back leg, revealing the other side of this mortise.
Using the hole in the back leg as a sight line, Tyler drills a corresponding hole through the front stretcher. (figure K) Again, he stops when the bit barely pokes through. With this stretcher already shaped, he carefully drills through the opposite side to complete the mortise.
Tyler spoke shaves the back leg and stretcher, then applies glue and inserts the back leg tenon into the seat mortise, again using a wedge to strengthen the joint (figure L). Then he glues and inserts the back stretcher into the back leg and front stretcher mortises and wedges the ends. (figure M) He lets the glue dry overnight.
After scraping off the excess glue, Tyler removes all protruding wedges and tenons with a Japanese saw. (figure N) Then he uses the combination of a block plane and chisel to soften the corners of the chair (figure O). Using a cabinet scraper, he smoothes the seat area flush with the leg tenons.
Finally, he applies 2 coats of linseed oil and allows the chair to cure overnight. (figure P)In the next segment, Tyler crafts his own deluxe workbench, the heart of the woodworkers shop.
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