Friday, February 19, 2010

Table Making- Shape and Profile

I started the day by laying out the lines for the table arcs on the bottom of the top. I will be jigsawing to the line, and the jigsaw is a coarse tool that tears out to the top of the cut. I layout on the bottom so the tearout will be removed when I rout the profile on the under edge.





I could pattern rout the arcs clean, but I chose to fair the curve with handtools today. I clamp the table together by the rails, tightly to prevent chipout when I work the endgrain across the division between the halves. I only worry about getting the top edge perfect, the router bits bearing will reference off this edge. Hollows left by the jigsaw blades flexing will be removed while profiling.



The leaves are now too long.



I work them to length one at a time, using the finished table proper as a guide.

I begin by scoring the leaves with a chisel, to prevent blowout.



I then clamp a plywood straight edge as a guide for a pattern routing bit. I cut as close as I can without touching the finished table edge.



I then use a handplane to trim the leaf to the right length. I work in from both sides to prevent blowout.



After all three leaves are done, I put them into the table and use web clamps to hold it together. I tighten these as much as I can, I want each leaf to support the next to prevent blowout when routing.

I give the bottom edge a 1" radius roundover. I climbcut when working against the grain to prevent damage, the chalk arrows show my feed direction. I make three passes.



I prefer a variable speed router when pushing big bits. They vibrate too much at full tilt.

I did have a little grain tearout.



To repair it I sand it until the void is full of dust, then apply cyanoacrylate glue.



While it is wet, I sand it more, packing dust into the wet fill.



CA is great stuff, but you must not let it sit too long on a surface, as it will prevent finish penetration.

I then sand the routed edge with a orbital sander at 120 untill the machine marks are gone. I then sand with 150, 180, and 220 by hand, backed by a worn out sanding sponge. I then use a random orbit with 120 to clean up the scratches on the bottom surface around the perimeter left by the hand block and the router.



I now turn my attention back to the skirts. The clients didn't like my initial design, they favoured this one instead.



I began by cutting a lip on the bottom edge of my milled skirt stock.



I then mill a poplar scrap as it's mate.



To make a jig to tablesaw the cove, I used a scrap piece of 3/4" plywood. I screwed a front and back fence to the base, keeping the screws well countersunk and away from the blade area.



I clamped the jig very tightly to the tablesaw perpendicular to the blade.



I raised the blade until 1/16" protruded above the jig base, then slowly passed the stock betweeen the fences.



I repeated this process several times, raising the blade no more than 1/8" at a time, until the cove was at full depth. For safety I clamped a scrap behind the fence to cover the emerging blade. I used a push stick, but only applied pressure over the rear edge where it was supported. I let the dust pile up, eventually it plugged its own holes and was carried down into the saw where it was sucked up by the dust collector.



I make at least two passes over the blade at its final height. This ensures I have a consistent cove, and it reduced the number of deep scratches that need to be removed. Tablesawn coves are difficult to sand clean, I'll use a gooseneck scraper. From what I understand, tablesaw moulding heads leave a nicer finish in fewer passes.

2 comments:

  1. Will do.

    Is there anything you want to see more of? Anything I'm not clear about?

    ReplyDelete

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I'm a woodworker on the Canadian prairie.