DIY Network

Coopered Glass-Top Table: Assembling the Columns From "Wood Works" episode WWK-509

With the, jarrah stock milled and angle-cut to form the staves for the coopered base, assembly of the base columns can begin. First, the staves are glued together to form the two curved columns. Biscuit joinery is used to prevent slippage in the staves. Once the glue-up is complete, a special jig is then created to cut the angles on the ends columns -- allowing them to lean inward and to support the flat glass-top.

This demonstration shows the steps involved in assembling, cutting and shaping one of the two columns. Simply repeat the steps identically to make the second column.

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	Figure A
	Figure B
	Figure C
	Figure D
	Figure E
	Figure F
	Figure G
	Figure H
	Figure I

Materials:

Table saw
Jointer
Biscuit joiner
Wood biscuits
Band saw
Jig saw
Random-orbital disc sander
Hand scraper
Straight-edge
Carpenter's pencil
Carpenter's tape
Yellow woodworker's glue
Glue roller and glue brushes
Clamps
Safety glasses or goggles

Safety Alert: Always wear safety goggles or safety glasses when
working with wood, power-tools, saws, drills, routers, etc.

Assembling the Columns

When gluing up long-grain to long-grain, joinery is typically not required. However, for coopering, some joinery may be needed to prevent slippage. For our curved base columns, biscuit joinery is used to keep the staves aligned.

• Mark the staves for the locations of the biscuit slots. We positioned ours with one slot 6 inches down from the top, one 6 inches up from the bottom and one directly in the center of each stave (figure A).

• The exceptions are the end staves of each column that will later be tapered. Since each column will taper from 18 inches at the bottom to 14 inches at the top, removing the extra stock would expose the joinery. Mark the end staves for each column as a reminder not to cut slots in these pieces.

• Set the fence of the biscuit cutter to match the 4-degree angle-cut on the edge of each stave. Following your layout marks, cut the slots (figure B) and position each cut so that it's centered in the thickness of the stock.

• Because biscuits are being used, each column can be glued up in two halves. Angled cauls will help to maximize clamping pressure by creating two parallel sides for the clamps to hold onto during glue-up. Before glue-up, conduct a dry-fit using the angled cauls and clamps (figure C). Once you've conducted a successful dry-fit, you can begin glue-up.

• Use a glue-roller to apply yellow glue to one side of each stave (figure D). Also apply glue to each of the biscuits and set them into the slots.

• Roll glue onto the other side of each stave and insert glued biscuits into the remaining slots (figure E).

• Add the angle-cut cauls to the outside of the assembly, and apply good horizontal clamping pressure to form the curve. Where the biscuits were omitted on the top of the two outside, add vertical clamps to hold those two staves aligned (figure F).

• Once the two halves have dried, glue the two sections together using more glue and biscuits (figure G).

• With the pressure of the clamps, there may be a tendency for the two halves to bow upward. To prevent this, set a long caul along the seam and apply downward clamping pressure (figure H).

• Once the caul and clamps are in position, let the clamped assembly cure for several hours. Once it has dried, remove any excess glue using a hand scraper (figure I).