Technique for square through-holes

[Gene Davis]

I built a prototype of a medicine cabinet, and its sides have some decorative square holes. See the pics, below. I have only dry-fit the assembly and will knock it apart to tune up some joints by doing a little shaving here and there.

The holes were cut using a forstner bit with diameter smaller than the hole, drilling from each side. The sides were then chopped and pared with chisels. I would like for it to be more perfect than it is.

How would you do these holes?

Species for this one was eastern white pine, $24 in lumber. The real deal will be mostly red birch, with the back panel of some old-growth SYP heart pine I have leftover from something.

The Sketchup model for this, complete with all joinery, is up on the 3D Warehouse. Search for "medicine cabinet with mirror" and you'll see it.

[Metod Alif]

Gene,
How did you use the chisels? If freehand, then you could 'improve' the holes by using a guide block. It would be a piece of wood clamped right at the 'intended' edge of the hole/mortice, with the chisel placed against it. Maybe somebody will chime in with a more accurate or faster approach.
Best wishes,
Metod

[Jim Matthews]

+1 on Metod's method using a guide block.

If the through holes are regularly spaced, a guide block with formica glued to the side could be easily clamped
along the work face and moved to the next row of holes.

I would make a plywood frame to fit all the way around the holes, clamped to the sides.
Chop half way from the outside (show face) first and finish off from the inside to avoid blowing out the fibers.

If you employ a forstner bit to "hog" out most of the waste, use a smaller one, to get into the corners.
I would drill the four corners close to the periphery (for this piece, that's a lot of holes) using a fence so they are all the same distance from the edge of your workpiece.

Follow that with either a pad saw or coping saw, which would get you very close to your layout line.
Using Jeff Miller's paring jig is shown in the following YouTube video (http://www.youtube.com/watch?v=FaZOFWB14-Y) around 3:25 in.

As Metod indicated, a paring jig allows you to maintain a vertical aspect by effectively raising the sidewall several inches.

If you're cutting 24 of these, score all mortises crossgrain with a knife.
This is the last line where your chisel should register for your final fit.

Lastly - I think the "lowest" through mortises are a little close to the end of the board.

A tusked tenon will exert some substantial pressure against the side panel, at the bottom.
Unless there's a crossgrain batten under the lowest shelf, the risk for that unsupported bit
of straight grain is to split out under a load or blow.

[Jamie Buxton]

With that many square holes to make, I'd seriously consider ripping the side into five pieces, jointing the ripped edges, crosscutting the second and fourth piece to take out the holes, then gluing everything back together. I'd sand the crosscut faces before the glue-up.

I can't tell from the pics, but if the bottom holes are not aligned with the holes above them, you'd have to move them.

[Joseph Tarantino]

in addition to the above, scribe the layout for the square holes with a marking knife. most #2 pencils aren't sharp enough. attack the clean up from both sides with either guided sharp chisels or perhaps a hollow chisel mortiser.

[Alan Schaffter]

With that many square holes to make, I'd seriously consider ripping the side into five pieces, jointing the ripped edges, crosscutting the second and fourth piece to take out the holes, then gluing everything back together. I'd sand the crosscut faces before the glue-up.

I can't tell from the pics, but if the bottom holes are not aligned with the holes above them, you'd have to move them.

+1

The strength of a long grain glue-up using modern glues is actually stronger than the wood itself.

[Kevin Jenness]

I have done large square holes like this with a forstner bit followed by a router template with a small diameter pattern bit and a sharp chisel. The corners could be cut first with a hollow chisel mortiser if the offset from the workpiece edge was within the mortiser's fence capacity. You would need to cut in from both sides to prevent tearout on the exit, and the boring bit might overcut the square outline slightly.

[Art Mann]

You didn't mention what tools are available to you. A lot depends on that. I would cut the square holes with a jigsaw. I might try cutting the corners out with a mortising machine. I must admit I am not very skilled with chisels and I don't have the patience for it.

[Phil Thien]

With that many square holes to make, I'd seriously consider ripping the side into five pieces, jointing the ripped edges, crosscutting the second and fourth piece to take out the holes, then gluing everything back together. I'd sand the crosscut faces before the glue-up.

I can't tell from the pics, but if the bottom holes are not aligned with the holes above them, you'd have to move them.

+2.

When you glue up the sides, use blocks of wood covered in wax in the holes to keep things aligned.

[Dave Richards]

Gene, that's looking nice. I was going to suggest you rip and reglue as Jamie described.

FWIW, the original plan from around 1910 showed tusk tenons as Gene has made in his. The original was 6 inches deep (a bit more than an inch deeper than Gene's), however, and the case is made up of stock that is only 5/8" thick. The extra depth allows for wider tenons.

This is drawn from the original plans although I removed the tusks, shortened the tenons and beveled their corners.
http://farm6.staticflickr.com/5345/8854823186_e9bbdd23f6.jpg (http://www.flickr.com/photos/8294157@N08/8854823186/)

[Alan Schaffter]

Gene, that's looking nice. I was going to suggest you rip and reglue as Jamie described.

FWIW, the original plan from around 1910 showed tusk tenons as Gene has made in his. The original was 6 inches deep (a bit more than an inch deeper than Gene's), however, and the case is made up of stock that is only 5/8" thick. The extra depth allows for wider tenons.

This is drawn from the original plans although I removed the tusks, shortened the tenons and beveled their corners.
http://farm6.staticflickr.com/5345/8854823186_e9bbdd23f6.jpg (http://www.flickr.com/photos/8294157@N08/8854823186/)

That gives a better idea of the size and location of the decorative square openings and mortises. Again I would go with the rip crosscut and glue method for the four decorative squares, then after it is glued back together use a hollow chisel mortiser or drill and chisels for the two mortises. The only place the mortises need to look good is at the outside face. Unlike the decorative openings, all other edges will be hidden.

[Sam Murdoch]

A coping or fret saw with a deep throat and the right blade could do this nicely too.

[Gary Herrmann]

Nothing wrong with the way you did it. Especially if you're going to peg them as shown. A guide block will help, as has been mentioned.

Remember this too: Nobody else will see that it's less than perfect. Don't point it out to anyone. Keep it to yourself and try for greater perfection next time, if it really bothers you.

[Jim Matthews]

The idea of ripping the entire side into five strips to make six little holes in the last 4 inches of a panel -
I'm sure that would be effective, but it's neither elegant nor appealing to this galoot.

Fiddling together strips this long to reconstitute a panel (that was likely chosen for it's appealing grain and solidity) is adding a machine step to make up for limited skills.
He's making a cabinet - not a cutting board.

There's no need to do it this way, unless you're making hundreds of them.

Make it (so much as you can) by hand - you'll know that every mark, joint and fitting are yours.

[johnny means]

Sounds, to me, like an excuse to get one of these.

http://m.youtube.com/#/watch?v=rjckF0-VeGI&desktop_uri=%2Fwatch%3Fv%3DrjckF0-VeGI

[John Sanford]

Hog out the waste with a drill bit. Square up the result either using a corner chisel, or there are even some square hole punches (http://www.leevalley.com/US/wood/page.aspx?p=65380&cat=1,43456) specifically designed for this application. If neither of those options appeal, then square 'em up using guide blocks as others have suggested. The rippin' and reglue would be my last option.

[Curt Harms]

Sounds, to me, like an excuse to get one of these.

http://m.youtube.com/#/watch?v=rjckF0-VeGI&desktop_uri=%2Fwatch%3Fv%3DrjckF0-VeGI

Here's the non-mobile youtube link:
http://www.youtube.com/watch?v=rjckF0-VeGI

I recall Roy Underhill demoing an antique version of that device. I've seen it on Roy's show and now on youtube and still don't really understand how it works:confused:. It's tough to be dense sometimes :p.