Cutting the decorative square through-holes

[Gene Davis]

I'll begin this build tomorrow, and am here to question my technique. It's a sofa table or hall table, design after an original from around 1900, done by Charles Rennie Mackintosh.

2015-02-11_2240.jpg

The six 3/4-inch-thick plank legs all get three 1-1/2" square through-holes, and we'll see their inside faces. The holes are decorative.

I did a dining table with holes like this in the wide plank spindles of the trestle frame ends, and for that, I ripped the boards, chopped the center rip to make for the holes, and carefully reglued. It came out pretty well, but I would have preferred a through-cut if I could do it perfectly. No seams at all, no matter how well-sawn and rejoined. The sawing and required jointing removes too much material, and the grain gives the joint away.

I don't own a corner chisel, but I have a pretty nice collection of bench chisels, and keep them scary-sharp.

What technique would you use to do the through-holes?

[Ian Scofield]

Forstner bit to remove most of material and use your bench chisels to remove the rest in the corners? Interested to see what others come up with

[Jeffrey Martel]

Drill a hole and use either a Jig Saw or a Coping saw to cut it square. Clean up with chisels.

[mreza Salav]

scroll saw, and then file/sand clean.

[Jamie Buxton]

Do the corners of the hole have to be exactly square? If not, you could do this with a plunge router, a template guide, and a 1/4"-diameter bit. It would give you 1/8" radius corners. The router gives nice clean sides to the hole, and a clean exit on the back side. It'd also be faster than hand-chiseling all those holes.

[Mike Schuch]

1/4" diameter straight router bit on a plunge router with a square template would leave a lot less wood to remove in the corners. You might even decide you like the 1/4" rounded over corners inside the squares and leave them? Or you could knock out the 1/4" rounded corners with a rasp or small flush cutting Japanese saw.

It looks like the legs are tapered. I would cut the squares before you cut the tapers in the legs. This way you could make your square template register on the edges of the untapered legs making it really quick to line up the template.

[Michelle Rich]

I too have avoided making these square decorative or thru double tenon type cuts, and when I do I hold my breath. I have resorted to the methods above & leaving the little tiny corners when using the router ideas above. They look OK to me.

[Floyd Mah]

Here are some tools that work well to refine the surfaces once you have roughed in the holes:

Iwasaki files These come in various sizes, but the most useful to me have been the extreme fine grade. These are not rasps. They are more microplanes and produce very fine cuts. You will be able to get a nice result. I use them all the time to fit joints and trim wood.

Skew chisels You don't have to buy these. I made a nice set using some cheaper bevel edge chisels by grinding a new shape to them. The nice thing about using these type of chisels in a cramped space like a hole or a dovetail is that advancing the chisel actually pares at a 45 degree angle from the direction of the chisel. As with any paring with a chisel, you need a sure hand, but this allows you to easily trim the corners of your square holes. Generally, you need a pair of matched chisels, especially if you can't flip the work. Also, remember that the actual edge is longer than the stated width of the chisel, that is, a 1/4" chisel has a cutting edge of 3/8". I've found the smaller chisels easier to handle (less resistance because of the narrower chisel).

[Gene Davis]

Well, thanks, y'all!

Just back from the big nearby town, where I was prepared to go to three different sources to see what I could get in rift, either cherry, red oak, or white oak. Lo and behold, the first stop, Frank Paxton, had a whole bunk of ten foot clear select white oak, and on sale at $5.95/bf. I went through the bunk to get the wide stuff I needed, and have it home. What a score!

I'll try the chop with the plunge router and a template and a nice spiral upcut 1/4" bit I have, to see how it looks. Maybe the corner rounds will look good to me for this piece. I may go through the center of each hole first with a 1" forstner, to keep the routing a little less scary. Have pattern-routed a lot of through circles at diameters of around 2 inches, and have always used carpet tape under between the workpiece and the sacrificial under-board to keep the center waste from flinging around when the cut goes through.

[Kent A Bathurst]

I would use a template, with all three holes in it, and the router. Of course, be sure to use a sacrificial backer board underneath. Chisels to clean up the corners.

Well, actually, I would not do that - I can reach the 4 corners with my PM mortiser..............So I would just lay it out with a pencil and whack away. But - I figgered that is not an option for you.