Introduction: The Most Over Engineered Shelves Ever

About: I’m am Systems Engineer (nothing to do with IT) by training, in my spare time I love designing building, making pretty much anything. I also love doing new thing, going to new places and being outside. I reall…

I built these shelves for my girlfriend now fiancé (thanks very much) so she could fill it up with all here Uni work.

For some reason I really like building shelves as you might noticed if you check out my other instructables. Unlike the last set made of pallets with a small set of hand tools this set was far more engineered.

Before you stop reading because you don't have a CNC machine just so you know I don't either - more on that later

There are many firsts for me on this project but I am supper happy with how it all came out and hope you like it and consider having a go.

Top level process, I will go through each step in more detail in each section

1. Design

2. CAD - Onshap (Free) -

3. CNC process - Southwest CNC (UK) I was pleasantly suppressed at the cost for materials, cutting and shipping ~£120 (that also included a whole sheet of 18mm ply)-

4.Dry fit and brackets

5. sanding and finishing

6. Installation

7. Other bits

8. happy fiancé ( im still working on this)

Step 1: Design

Overall concept - New meets old
I like traditional wood working and the use of wedges and dowels instead of screws and glue. I also like computerised manufacturing techniques (3d printing, CNC machining, laser cutting, etc). So I wanted to see if you could blend the two. So I set about building CNC machined flat pack shelves with no glue or screws (apart from to mount to the wall). I ended up using a joint similar to the tradition key mortise (see pictures) and tenon. I also chose to make it out of ply wood because it is structurally stable, available, cost effective and I think the grain and end grain can look really good.

I measured the wall to see how much space I had to play with. I then measured some of the key things that were going to go on the shelf such as printer, box folders etc.

I drew the space envelope to scale in my sketch book then started dividing up the space to see what would work.

I liked the idea of having a set of interlinking boxes and went through many iterations of how to join them without any hardware or glue. The end resulted is both scalable in size and scalable in how many boxes connect to each other.

The coloured CAD drawing and line drawing show a number of configurations that the shelves can be assembled in the numbers of each component vary depending on the configuration.

The set i built consists of:
2 ends (yellow)
1 centre (red)
4 shelves (blue)
8 shelf or reinforcers
32 pegs

Wall Fixings
The wall mounting solution was harder then I thought and it took me a while to find the right brackets. I didn't want them to be seen so I had to be able to hide them.

These are the ones I selected (£4.50 for 10)

I wanted to see the wood grain and end grain so I knew every cut scratch or mark would be hard to hide. considering this up front is a good step as paint can add thickness to material that can mess up any tight tolerances

Step 2: CAD - Try Something New

I have used a number of CAD packages before and my go to was sketch up. For this I thought I would try something else and had recently discovered Onshap. Onshape is a free (size limited) browser based CAD programme. It is really intuitive to use and there is some really good tutorials. If you are interested check it out I recommend it, you can also get access to my models and use them for yourself.

One really good feature is collaborative working this allowed me to share the model with southwestCNC for them to make changes or recommendations that would assist with manufacture.

I designed the model with 0 tolerances in most places this worked well as it meant when the material was delivered to the machine shop they could measure it (as 18mm ply is rarely 18mm in reality) and scale my design to fit.
Captain hindsight - I should have added some more tolerances in areas that would not be visible as this would have saved some sanding later.

Dog and Bone
Q. how do you cut a square hole without rounded corners with a round cutter? A - you cant (im sure some one is going to prove me wrong)

What you can do is drill a small whole in each corner first then cut between them this leaves a shape a little like a bone. This has two advantages. No chiselling out the corners to make them all square and the square peg doesn't bind up as much when you are putting it in the square hole. The pictures show the cad drawings and an example of a finished bone aperture.

I designed all the individual pieces then assembled them together in Onshape.

Step 3: CNC

SouthwestCNC (UK based) they were recommended to me by a friend and I am so glad he did, so I am passing that recommendation on to you. They are a small family firm and charge a flat rate per hour for cutting. I spoke to them on the phone and when my model was close to ready I shared it with them in onshape. They suggested the bone fillets method and edited an example in my model I then did the rest and it was ready to go.

SouthwestCNC used their software to lay out all the parts in the most efficient way. I asked for all large panels to be placed at 45deg to the grain for aesthetics reasons and it meant that most long edges will be cut across the grain of each ply (not with it). They relayed it and managed to fit it all on one sheet at 40deg.

They gave me options and a recommendation for ply and brought it in. They don't just cut ply there is a large range that they can cover.

They packaged it up for me and delivered when I requested. They kept me informed through out and where a joy to deal with.

The pictures show the sheet on the CNC machine (i borrowed it from there website) and the unboxing process

In the process I mentioned that I would write this up and would be recommending them on instructables and they have offered 5% off any cutting time to anyone that quotes instructable Tim if you place any orders.

check out their website

Step 4: Dry Fit, Brakets, Sand and Finish

I dry fitted all the pieces and the joints were tight just like I asked, a little to tight in places.

I marked up all the bits so they will go in the same place and orientation each time. Mark them in an area that will be covered after assembly

I marked up the corners for the brackets and use a fine saw and sharp knife to cut accross the grain down to a depth of about 1-2mm. I then use a sharp chisel to cut away the top plys. This is just so that the bracket sits in a little recess and helps hide them. This could also potentially be done by the CNC machine.

Step 5: Sand and Oil

I gave every thing a sand with 120 grit glass paper. There where a few spots that where just a little to tight so I used some glass paper and a chisel where needed.

tip - if you have little pieces to sand clamp your sander and hold the little piece

I used teak oil for the finish I raged it on wiped it off let it dry. Next I went over with some wire wool and very fine sand paper. I repeated this process twice. The picture shows how the oil really brings out the end grain.

As I had about 40 pegs to do I filled a small container with the oil and dipped them in.

tip - the first coat will suck up quite a lot of oil and will take a bit of time to dry. leave a day between coats and a few days before assembling for the final time if possible.

Step 6: Install

Tools required

  • Hammer Drill
  • hammer
  • level
  • Tape measure
  • punch


  • wall plugs
  • brackets (6 in total)
  • screws (i used round head pozzi screws)

I drilled some holes in the back of the shelf so I could get the shelves tight up against the wall once I had screws the breakers on.

I marked out the first brackets and fitted them to the wall using two wall plugs and two screws. then offered up the shelves and marked the next bracket.

captain hindsight - this requires quite a lot of accuracy as there is very little adjustment available in the brackets. need to rethink mounting solution

Once i had fixed all the brackets to the wall i offered up the shelves and screwed them in at the top and bottom.

(my girl friend was rushing me so I forgot to take a picture of all 6 brackets installed before I put the shelves up)

Step 7: Leasons Learnt and Other Ideas,

1. this was a fun project but was far from the hands on method that I normally use and took much longer but am supper happy with the finished product

2. much cheaper than I thought it would be to get this machined. about £80 for the cutting time

3. it was harder to mount to the wall than i thought. Maybe have a look at kitchen cupboard fixing they have some adjustment but are bigger and cant be as well hidden

4. combining old methods with new manufacturing works well.

5. i make better flat pack than ikea

Thanks for reading

I hope this gives you some inspiration if you would like any further information drop a comment and I will get back to you.

If you like these please vote for me in the shelf competition and i hope to bring you more soon.

Shelving Contest

Participated in the
Shelving Contest