The Cot Project


Back in February this year, knowing I was going to become a daddy pretty soon, I decided that I wanted to build a good quality, solid cot for my soon-to-arrive baby. At the time I still had a good 7 months before the due date and figured I’d have plenty of time to complete the project. Looking back on this (after a total of 9 months!) I realise that it was actually quite an ambitious project! My daughter did finally get her birthday present, although it ended up being over 2 months late 😉

However, even after all the hard work, blood, sweat and tears, I am really happy with the end result.

To start with I began doing quite a bit of research into cots. At first I figured that the designs were all pretty similar and that building it shouldn’t really be too much more involved that cutting and planing a few boards and sticking them together with mortise and tenon type joints. However I soon learned that there would be a little more to it than this.

There are actually quite a large variety of cot types, with various different sizes, styles, designs and functions. There are drop-side cots with a multitude of drop mechanisms, multi mattress heights and cots which convert to children’s bed afterwards. Not only that but there were also a number of quite important safety considerations to take into account…and let’s face it, when you’re dealing with your own child, you really don’t want to get that type of thing wrong. I also found that there was actually a British Standard (BSEN716 for anyone who’s interested) which outlines the minimum standards that a cot should adhere to in the UK!!

So after quite a bit more research, I settled on a set of minimum criteria which my cot needed to meet:

  • The cot has to be deep enough to be safe enough for a baby
  • The cot must not have any protrusions at the top (i.e. on the corner posts) which something could get caught on
  • The bars must be no more than 5 cm apart and no less than 2.5 cm apart
  • The finish used must be child safe
  • The mattress must fit snugly into the cot and shouldn’t be more than 3 cm from any edge at any time

This was beginning to sound like quite a daunting project after all…but nevertheless I decided to go ahead with it. I figured that if all else failed, I could always just give up and buy one if it came down to it.

The next step was to design the cot. I work with 3D modelling packages as part of my job, and so I have quite a bit of experience of modelling in 3D. This meant I could quite easily mock up the cot on a computer and work out very accurately what my measurements would be and therefore how much timber to buy.

You can see from the picture how I modelled the cot and then exploded the parts and used measuring tools in the software to figure out accurate dimensions.

My cot design called for a few pieces to be created and then fitted together using mostly mortise and tenon style joints. I based the dimensions on a standard cot mattress but planned to buy the actual mattress before making final measurements so that I could ensure the size would be correct.

The most complicated part of this build would be the tops of the headboards as they were designed to be rounded. This was done to meet the safety criteria that no protrusions should exist on top of the posts. By rounding it off, I also ensured that if anything did get caught on the top, it would just slide off again and prevent any horrible accidents.

For the initial design I had planned to mortise and tenon the entire cot together and use glue in all joints. However it became apparent to me during the build that if I were to do this, there was no way in I would ever be able to fit the completed cot up the stairs to the nursery…not to mention that it would weigh far too much to lift! So I sensibly updated my plan to make use of cross dowel bolts fitted in the rails to hold the sides and mattress base to the headboards. The mortise and tenons would still be used for strength, but the addition of the bolts meant that it would now essentially become a flat-pack project consisting of 5 separate pieces.

The 5 separate pieces of my cot design to be held together with mortise and tennon and dowel bolts

Once I had the final measurements I got in touch with my local timber yard and put in an order for enough American Ash to complete the job. I decided on Ash because it was a good compromise between quality and cost. I would have preferred oak, but at the time it was almost twice the price so decided that I would go with the slightly cheaper option. Ash also proved to be pretty easy to work (easier than Oak) and has very large open grain which I really like.

When I drove over to collect the wood, I don’t think I had really comprehended the sheer amount of material that I had actually ordered! I was somewhat shocked to see a large forklift truck bringing over an enormous pallet holding 12 massive planks of wood. Initial shock over, the guys at the yard and I finally managed to squeeze it all into the back of my car, and with the boot tied down and wood strapped in tight I managed to get it home safely.

You can see from the picture just how much timber I ended up with!

With the planks safely at home I could plan out how I should go about cutting required parts. I measured the planks and drew up a cutting plan which showed me how each plank should be cut to ensure I had the correct pieces left over at the end. This was a pretty critical part of the build since if I were to cut wrong I could end up not having enough material at the correct size to make all the parts. I again designed this plan using a 3D modelling package on the computer.

Cutting plan for initial planks

Cutting the wood down to size was a little tricky since I don’t own a table saw or band saw. Instead I had to rig-up a crazy cutting setup using my two saw-horses, a load of clamps and a big bucket of weights! I then had to use my circular saw to make all the cuts. The thinner boards were pretty easy to cut but the thicker ones took ages as my circular saw blade wasn’t big enough so I had to resort to using a hand saw fort those.

Bit of a mad setup using saw-horses, clamps and weights to cut the timber to size

The rough cut pieces ready to be planed and thicknessed

The next step was to plane the rough cut pieces, squaring the edges. This is probably the most important parts of any build. Without a squared edge, its practically impossible to get things straight and true when putting them together.

Until this point I had only ever planed wood by hand. However given the scale of this particular project I decided it was probably wise to invest in a half decent power tool to do the job. I think if I’d tried to hand plane all of the parts of this cot I would still be building it by the time my daughter went to university!

Most freestanding workshop planer/thicknessers are pretty expensive, and to be honest to get a really good result, you really should be looking at spending a lot of money. However my needs were for moderate accuracy and low cost. I spent quite a bit of time looking at all the various makes and models of planer/thicknessers and eventually settled on a bench-top version sold by Axminster which was just under £200. It was quite favourably reviewed on the website and so I took the plunge and ordered one. I have to say that it was a good move. The tool has turned out to be absolutely fantastic value for money and helped me rattle through all the hard work in a relatively short amount of time.

Planing thick stock on the bench top planer

Planing long pieces on the bench top planer

Planed square-edged boards all done on the bench top planer/thicknesser

You can see from the photos that the end result of the planing left the timber with a pretty smooth finish. However at this stage, I didn’t thickness the boards down to their final dimensions. What I did was to bring all the separate parts into the house and store them for several weeks in the room where we intended to keep the cot once it was complete. The reason for this was to allow the boards to acclimatise to the room’s conditions. Often wood still has some moisture in it when bought from the stockist and so by leaving it in the house for several weeks the wood has a final chance to dry out, and potentially warp and bend a little as it does so. By leaving the thickness greater than the required final dimensions, the theory is that there is still enough material that can be taken off to remove the bends and twists.

One side effect of all the planing was that I generated an awful lot of wood chippings and sawdust.

Just some of the wood chippings created by all of the planing and thicknessing

At first I threw the chippings away but after a bit of research on eBay I discovered that there was quite a bit of demand of this type of material as pet bedding. So in the end I sold about 6 bags of chippings on eBay for close to £3 each! Not bad for something which, as far as I was concerned, was a waste product!

Eventually, once all the wood had been resting in the nursery for a number of weeks and had then been thicknessed down to the final dimensions, it was time to start cutting the joints!

I started by creating the stub tenons on the numerous cot slats. In total this project called for 34 individual slats to be built, 13 thin ones on each side and 4 thicker ones on each of the head and foot boards. These were to be slotted into both the side support beams and the headboard supports along the tops and bottoms. I had thought over a few methods of how I might achieve this, ranging from cutting each mortise by hand to simply using dowels. In the end the simplest solution seemed to be to cut a channel through the length of the supports and then cut a stub tenon on each slat to slot into the groove. I could then use small blocks to fill the gaps between slats. All of the grooves could be cut on the router table, meaning it was nice and repeatable and not too labour intensive.

My home-made router table, set up to cut all stub tenons on the cot slats

Using the router table to cut stub tenons

A close up of me routing a stub tenon

It took a while but eventually all tenons were cut and the grooves in the supports were also cut.

All stub tenons complete

Close up of completed stub tenon

At the same time as cutting the stub tenons and groves I also cut the tenons on the rails and head/footboard supports using a combination of router and hand tools. These tenons needed to be done with a little more care because they needed to fit into a hand cut mortise and therefore hand to be the right size for the hole I was going to make. If I cut them too small, they would be too lose fitting and therefore compromise the strength of the completed cot.

One of the side rails with the channel routed down the middle and the tenon cut for the as yet uncut mortise in the leg

The headboard and footboard panels also needed the channel and tenon creating. However I left the final mortise uncut until I had rounded the headboard panels

As you can see from the above photos I cut the tenons on the rails and head/footboard panels first. I knew the width that my mortises were going to be because I based it on the thickness of the chisel I was going to use. However I wasn’t 100% certain about how high tall the tenons should be. So I left that part until after I had rounded the headboard panels.

Rounding the panels (as I already mentioned) was going to be really tricky. However I was quite clear on the requirements just due to the fact that my 3D design was so accurate. From my design I new that the round parts were actually part of a larger circle which had a radius of 120cm. This meant that if I could pin my router with a 120cm length of cord I could create a simple guide shape out of something like MDF which I could use as a template to cut the actual shapes.

The round tops of the cot were actually part of a circle with a radius of 120cm

I managed achieve this by using a bit of A-Team like ingenuity (or at least that’s how I like to think of it) by putting together the following items: a router, 120cm of stiff string, a workmate bench weighted down with lots of heavy stuff and a block of 2×4 with a large screw in the middle. I wish I had remembered at the time to take a photo of that setup, but sadly I don’t so you’ll have to use your imagination. However once the template was cut it was then just a relatively simple task of using a router fitted with a long bearing guided bit to cut the rounded shapes.

My curve template clamped to one of the panels ready to be rounded

A shot of the router cutting the curve along the template

One of the headboard panels cut using the router and curve template

At this point in the build I was getting quite a bit more confident about the progress. I had up until this point been a little nervous about how I was going to achieve the curved sections. However this method was really successful and I was looking forward to the rest.

The next step was to cut the tenons on the head/footboard panels to a more appropriate size. I could have left them as they were, but I was concerned that this would mean cutting too large a mortise in the legs and perhaps weakening the cot. So I decided on a size and made the cuts. I then cleaned up the tenons a bit on the router table just to keep everything neat and tidy.

I initially cut the bulk of the waste away with a hand saw

The tenons were cleaned up on the router table

Completed tenons on all head/footboard panels

With all of the tenons cut, I next had to chop out the mortises in the cot legs. There were a total of 16 mortises to chop so I had my work cut out for me (no pun intended).

The first stage in the process of chopping the mortises was to very accurately measure where on the legs they needed to go. A mistake at this point could really mess everything up. There was the risk that the cot might end up not being truly square or level. Referring to the plans it was easy to work out where the mortises needed to be and then just a case of being very careful about where to start the cuts.

Accurately measuring and marking out where the mortises needed to go reduced chances of mistakes being made

Once the mortices were marked up I needed to start the chopping. I could have just chopped all of the mortices with a chisel, however given the size and amount of the mortices it was quicker to actually drill out a lot of the wood first and then just clean everything up with a chisel afterwards. I could also use my portable drill press to do this and therefore ensure consistent drill direction and depth.

The setup I used to drill out as much of the mortises as possible. Using the drill press meant the mortises could easily be cut to a consistent depth

Using the drill I could easily remove a lot of the waste before starting with the chisel

Once drilled, I used my mortise chisel to do the rest of the work. It was much easier to chop out the mortise with the majority of the waste gone and also easy to keep the mortise straight and true. It also meant much less abuse for the poor chisel and so I didn’t need to re-sharpen it too often.

Once most of the waste was removed I could use the chisel to remove the rest much more easily and cleanly. It also saved the chisel from too much abuse

Completed mortices

As you can see I numbered every joint so that I could remember later on which mortise went with which tenon. With the top mortises cut I could then go for a test fit with the headboard panels

Test fit of the headboard panel with the legs

As you can see it was slowly starting to take shape. I still had a little bit of rounding off to do on the tops of the legs, so it was back to the tried and tested curve template method.

Using the same template as I used for the top panels I clamped the legs below the template ready for rounding

You can see the tops of the legs above the template which were to be removed using the router

Headboard test fit with rounded off top complete

At this stage in the project it became just a case of rinse and repeat. I had to chop the lower mortises in the same way as the upper ones and test fit them with the lower head/footboard panels. The following photos show this process.

In the same way as the upper mortises I had to chop out the lower mortises too

Once chopped, all 4 legs were identical

Test fit of headboard with upper and lower panels in place

At this stage I decided to also cut out the top rails for the cot. These were cut from a single large block of wood and I used the same curve template and routing method as I had used for the panels. The only difference was the time it took to cut due to the thickness of the timber. I had to buy a longer router bit to do it but it worked absolutely fine.

The top rails cut from a single piece of thicker stock using the template curve and router

Test fit of top headboard with top rail placed on top. You can see that the ends still needed to be trimmed at this point

The other mortises had to be chopped into the insides of each leg to accommodate the cot’s side rails. The methods used for this were exactly the same as for the head/footboard mortises.

At this point everything was cut and theoretically I could already assemble the cot. However there was still a lot of refining to do before it could be considered complete. Firstly I decided to tackle the sharpness of the squared edges. As this was an item of furniture intended for a small child it really couldn’t have any sharp edges on it at all. So I needed to round off every sharp edge which would be exposed in the final cot.

I fitted a round-over bit into my router and mounted it into the router table. Once I had set it at a depth I was happy with, I could again very easily repeat the round-over on every single part quickly and without too much time or effort spent. The only parts I could not do this on was the top rails which, due to the roundness, would not be straightforward on the router table. I decided to simply hand sand those instead.


The round-over bit fitted to the router table

This photo shows the parts before and after the round-over

Test fit of the headboard with slats all completely rounded over at the edges and top rail trimmed to size

The cot was really starting to take shape.

With everything nicely rounded it was time to work on the flat-pack assembly solution I had decided to implement. To do this I used some long cross dowels which were to be fitted through the outside edges of the legs and fed into the side rails and mattress supports. I would also drill a hole along the inside of each side rail and mattress support to hold a threaded dowel bolt.

I have to admit this was actually a lot more difficult than I had expected it to be. The problem was how to drill in to the parts at exactly 90 degrees without deviating, and then also how to drill the hole for the threaded dowel bolt. Drilling the holes in the legs was easy…just mark out where the hole should be and use the drill press to make the hole. However the hole in the rails was a lot more difficult. Because I was drilling into the end of a very long piece of wood, it was not possible to use my drill press. Also because the rails were so tall, it was difficult to hold the drill straight while making the hole. I managed to drill the holes, but I news that they were not perfectly perpendicular to the rails and so the next part (drilling the intersecting holes for the dowel bolts) was a real challenge.

After a lot of measuring and head-scratching I did eventually manage to get all the holes drilled (roughly) correctly. Some of the bolts were very close to not fitting correctly but with a bit of gentle persuasion they did lock together. I think if I were to do this again I would like to find a better method for this particular problem. I still can’t really think of a decent way of drilling into the end of a length of wood like this with complete accuracy.

The dowel bolts I used to implement my flat-pack design

Hole drilled into leg with inset for metal washer

Bolt fitted into drilled leg with washer

Drilled side rail with dowel bolt and cross bolt fitted

Having spent so much time on the headboards and general structural issues I had neglected one of the fundamental parts of the build…namely the sides. I therefore started to look at how the side slats would fit into the rails and then also how to fill the small gaps between the slats.

I decided to cut blocks which would fit into the gaps between the slats. These would serve three purposes; they would keep the slats apart by a uniform distance, they would strengthen the slat joints and they would also make the rails look much nicer.

To create the separator blocks I had to cut a few strips of wood which were thicknessed to exactly the same thickness as the rail grooves which I had cut earlier with the router. Then I would simply cut the strips into individual blocks. These blocks then needed to be glued into the grooves at the correct separation distance before the slats were fitted.

Test fit of side with slats in place

I cut the separator blocks from several strips of wood thicknessed to exactly the thickness of the grooves

The separator blocks were glued into the grooves at the correct separations

Completed side rails with separator blocks glued in place

Completed head/footboard panels with separator blocks glued in place

At this point all of the major elements were pretty much completed. There was one pretty daunting task still remaining however…finishing!

The first step in any finishing project is to sand everything to get it nice and smooth. I was not looking forward to this because there were simply dozens of parts, each had to be sanded with first 120 grit paper and then 240 grit sandpaper to smooth it up. The way I like to sand is to first mark the wood all over with a soft pencil. Then I sand the pieces with the current grit until all of the pencil lines are gone. Once that has happened you know that the surface is flat and you can move onto the next grit.

Fortunately at this time the weather was absolutely fantastic and so I could just head out into my back garden with my electric sander, an extension lead and my trusty workmate and just get sanding. You can see from the pictures that my dad also offered to help me out with this bit and between us we managed to get it all done in a relatively short amount of time.

By marking the wood with a soft pencil it is easy to tell when the surface is smooth once all pencil marks have been sanded away

My dad offered to help me out with the sanding…good job too, it would have taken me ages on my own!

And then it was only the staining left to do!

I spent a lot of time (and money) deciding how to stain the cot. I really didn’t want to spoil all of my hard work by just putting some horrible finish on the piece, but at the same time I had to ensure that whatever I did, the cot was safe for my baby daughter.

It took me a while but eventually I decided on a multiple coat approach. Ash is a very open pored wood with large (and in my opinion beautiful) cathedral-like grain patterns. I wanted to enhance that beauty in my finish but also keep the colour consistent. My wife also wanted the cot to match with the other items of furniture we already had in the nursery which were stained antique pine. Therefore I needed a way to dye the wood to match the pine colour but also pop the grain and make it stand out.

I did a number of tests which you can see below and eventually settled on a finishing solution.

Some finish tests I did on a board of Ash to try to get the colour and contrast correct

The way I eventually achieved the look I wanted, was to first dye the wood with a base colour which closely matched the pine colour my wife wanted and then to apply a pigment stain over the top to pop the grain.

Dyes absorb very well into tight grained wood and so gives a fairly uniform colour over the entire surface. However they don’t do a great job of highlighting the open grain patterns. Pigment stains on the other hand sit very well in open pored wood and therefore highlight the grain very well. However they don’t really absorb into tight grain and so if I had applied pigment stain alone the colour would probably have ended up quite blotchy and messy looking.

Adding the dye to the wood first

You can see the dramatic difference one coat of the dye made to the colour of the wood

Once the dye had dried I applied a coat of pigment gel stain to help pop the grain

This image shows the difference between dye alone and stain over dye. You can see that the grain is more defined on the stained wood

I initially thought that I would need to do a few coats of the stain, but when it was all done and dried, I actually really liked it and decided not to give it another coat in case it got too dark. However I did want to apply a top layer of some sort to both protect the wood and to protect my daughter. I spent a bit of time looking for a solution and eventually decided to use a wax paste. Wax is probably not the obvious choice as its not very hard wearing or water resistant, but I wanted to keep the rustic look without too much shine. I really wanted to avoid varnish which I personally am not very keen on.

The wax paste I chose was a clear wax and was classified as “Toy Safe”, meaning that it was fine to use on children’s toys and furniture and would not be dangerous to the baby. I applied a couple of coats of this over every piece and lightly buffed them, but not so much as to give a high sheen.

Applying Wax Paste

You can see the light sheen that the wax paste gave the the wood surface

Test fit of finished headboard

All that remained was to glue everything together. This was actually the easiest part of the build. The head and footboards simply needed gluing throughout. So I glued the slats and legs together and clamped it all up and left it to dry overnight. The following day I glued the top rail onto the top of the headboards and again left them over night.

Lots of glue in the mortises to hold the head and footboards together

Using clamps to hold the head/footboards together while the glue dried overnight

Again using clamps to hold the top rail in place while the glue dried

Completed headboard

The sides were a little more fiddly due to the fact that I had to get every single slat to sit in every single groove all at the same time. Once I had it set up however, it was pretty easy to apply the clamps to hold it in place. I also fully assembled the cot while the sides were drying to ensure that the sides would still fit correctly once dried. I was worried that I might over-tighten the clamps and therefore make the gap between the top and bottom rails too small. This seemed to work really well. I didn’t have enough clamps to do both sides in one go however so I had to split it over a couple of nights.

Finished side ready for clamping and glue drying overnight

The cot side clamped in place to ensure the parts will still fit once glue has dried

Other side clamped and glued up

One more thing needed to be done which was to fit the slats for the mattress base. I had always planned on using cheaper pine for these as they will never be seen. The slats needed to be fitted to the two mattress support rails which had a two brace bars running along them. I screwed the slats to these bracing bars at equal separations.

The two mattress support rails with bracing bars screwed to them

Screwing the mattress base slats to the base supports at equal separations

And with that…it was done!

The completed cot!

A full 9 months after I had started and a full 2 months after my daughter was born I finally completed my masterpiece 🙂

Looking back over all the steps, I am actually really impressed with myself for managing to complete the project to such a high standard. I am not a professional woodworker and have never had any training other than what I have read in books or seen on the internet, and yet when I see the cot now I feel very proud of what I have achieved.

It also occurred to me while writing this blog, that the solidity and aesthetic quality of the cot is actually pretty high, there is the very distinct possibility that the cot might very well outlive me! I would love to think that it will be handed down to the next generation, and even the generation after that and be well used. Who knows, it may even end up becoming an antique! All of my family keep telling me I should inscribe it with my name or something, but in all honesty I really haven’t got the nerve to take another blade to it in case I do some irreversible damage!

I guess by writing this blog I have at least made a record of my achievement and have a way of looking back in later years. If you’d read through this article, first of all, congratulations! its a pretty heft bit of reading, but second of all thank you. I hope you have enjoyed the post and that perhaps it has given you some inspiration or ideas about projects you could do yourself.

I’d love to hear any comments you may have, so please feel free to comment on this article.

And now because you’ve stayed with me this far, here is another pic of the completed cot just for you



Completed Cot in the nursery, complete with tree and forest animals