The boolean wall shelf

Making holes!

I am going to ship this shelf about 1800 KM, so I decided flat pack style was a good idea. That meant I needed to attach the shelves using some sort of hardware, and since I worked in a furniture shop back in the days… well, I know how to IKEA stuff!

Thumpin’ dowels

You can buy dowels readily made, or you can just thump them out from some gash. I made a dowel plate a while back. It is an 8mm thick piece of flat bar steel with a series of holes drilled through it, from 5 to 13mm at the moment. I hope to get it drilled beyond 13mm as well. Below 5mm and you can just use toothpicks if you insist on using dowels that small.

As a woodworker, I have developed a wood radar. Not a single piece of firewood is tossed on the flames without scrutiny! And so it came to pass that I found a log with VERY straight grain – poor thing was destined to grill a batch of bacon cheese sausages (they are REALLY good with some crisp fried onions, a bun, ketchup and mustard!), but I rescued it from the burn pile and split it to small blanks.

The process is simple: take a blank, and split it to a bit oversized from what you need. Whittle the end until it goes through the dowel plate slightly and start in the biggest hole it won’t pass through. Grab the ol’ hamma’ and welly away! Continue with the next biggest hole and thump it through. Rinse and repeat until you have the desired dimension. I highly suggest that you do two rounds on the last hole to ensure the dowel is the correct size.

You can click on the images for a larger version.

The next job is to cut the dowels to length. It is also a very good idea to cut a glue groove so that excess glue can escape when you tap – not welly, tap! – the dowels into their holes. If you don’t do it, you risk demonstrating how hydraulic systems can ruin the day when the forces finds an escape route you did not know about.

AND REMEMBER KIDS! You ALWAYS thump the dowels into the ends, never on the flats!

If you put the dowels into the table top and hammer them in, you’ll blow out the bottom of the dowel hole. Yes, I have indeed done that. On a rather expensive dining table, back when I was young and foolish. That was not a good day…

Drilling holes in the back panel

Let’s rewind a few clicks. Before I made those dowels, I drilled holes for said dowels and two bolts to fasten the shelves to the panel. I was very careful when I drilled the holes after I marked them on the edge of the shelves, but the drill bit did wander a smidgen. To the best of my abilities, I traced the center of the holes and transferred the locations to the back panel. I did it so that both shelves will be located 10cm from top/bottom of the back panel. 8mm dowels and 7mm screws was used.

I then drilled the holes. The dowel holes is not drilled all the way through (except for one where the drill – I blame the drill! – just blew straight through). The holes near the edges needed to be modified so that they can allow the back panel to move during the seasons. I used a file to make the holes for the screws oblong, with a target of +/- 2mm size hole.

For the dowel holes I used a carving chisel. This is quarter sawn white oak, so the wood should stay fairly stable – more so than what flat sawn wood would do anyway (that’s a mouthful of a sentence for ya!).

I drilled the screw holes in the panels so that the screw head just barely fit. The screws has a small lip on the very top, which is plenty for this application. Here is the oblong hole for the outermost screw:

By screwing the shelves to the back panel like this, I am actually using them as battens to keep the panel dead flat. The panel can move, but it won’t cup. Again, quarter sawn wood is helping out by being very stable in that regard.

I carved my initials on the back. I should make a logo and order a logo branding iron or something… But it is actually rather nice to just carve my initials like that. Hand made!

I chiseled out recesses for the metal keyhole hardware I’m using for hanging shelves. The router plane ensured an even depth so that the hardware is completely recessed into the back of the shelf – it’ll sit flush with the wall. The Ashley Iles butt chisels are great for fine work like this!

A short while later, two brackets were installed.

Before finishing, I assembled the shelf to check that everything was playing along nicely.,

Not bad! The finish should pop those rays pretty nicely!


I chose Osmo TopOil 3068 natural for this piece. It is a hard wax oil with a hint of white pigment. It will preserve the natural feel of the wood, the oil will pop the rays and the pigment will keep the piece from yellowing to a certain degree. It is easy to refinish / maintain down the line, and it is water repellant. This shelf will most likely hold some sort of plant, and any water spillage should not affect the finish.

I made my own “bench cookies” to hold the panel off of the bench top (I put clamps on the screws for the shelves, so they were easy to hold). Here’s my high tech solution:

KISS technology!

I applied three liberal coats using Osmo pads. The end results can be seen on the last page, so let’s head over there.

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