This is the baby bed with adjustable base height which I built for my daughter just before she was born. It doubles up as a day seat when you remove the front rails and gate (see image 3) when eventually the bed becomes too small for your child to sleep in. I wanted to share it with you because I think it is a nice but rather simple design and costs much less to build than to buy a similar design retail version.
For the materials, fittings, glue, screws, doweling, paint and varnish it cost about 130 Euros all together (about 150 USD). Of course I already had the power tools (drill, band saw, sanders, etc.) and there is some work to put in by hand. It took me around 48 hours of solid work over a period of 2 weeks to complete (mainly over some evenings and weekends and this is excluding drying times of glue, paint and lacquer).
I went for standard baby bed dimensions of 120cm x 60cm (48" x 24") so that we could buy and fit standard sized mattresses and bedding from the shops. The height is adjustable from the lower default position to a higher position for when the baby is still very young and needs to be picked up and put down multiple times during the day and night. This higher position saves a lot of stress on the parent's back with all of the lifting.
I hope you like it and I wish you a lot of fun building one! :-)
Step 1: Preparing the Base, Legs, Sides and Rails.
First of all a word about the wood - I used a pine (spruce) wood which I could buy in various sizes and two thicknesses, 2.8 cm and 1.8 cm, from our local DIY Home Improvement store (OBI). I decided to use this because it is a good priced, soft wood which makes it easy to work with. Some raw pieces I bought, such as the base and sides were already cut to the size I needed or needed very simple size adjustment. Other pieces like the legs and rails needed to be cut to size, shaped and prepared from larger pieces.
Power Tools, Hand Tools and Other Equipment:
Electric Circular Table Saw with Blade already installed for Wood
Electric Hand Sander (Small)
Sand Paper - 120 and 180 grade (to fit your Electric hand sander)
Electric Band Saw (with Wood Saw Band installed)
Cordless Screw Driver (fully charged) and a Set of Bits
Electric or Cordless Rechargeable Drill and a Set of Drill Bits for Wood
Flat Head Screwdriver and Cross Head or Posi-drive Screwdriver
Wood Glue (various types available at you local DIY Home Improvement Store)
Dowel, at least 86 pieces - 8mm Dia. by 40mm Long (see image)
Stainless Steel Screws, at least 16 pieces - 4mm Dia. x 30mm Long (see image) - Stainless steel does not rust which is therefore a safer material to use for a baby/child bed. Also in the name of safety I kept the number of screws down to a minimum, only 16 in total.
Brass Bolt Assemblies  - for securing the Gate (see images)
Wood Drill Bits - 8mm and 3mm
Countersink Drill Bit
Baby/Child Safe Paint and/or Lacquer - USE ONLY OFFICIALLY APPROVED BABY/CHILD SAFE PAINT AND VARNISH!
Brushes for the paint and Lacquer
Cloths for wiping up paint drips and a clean damp cloth for wiping surfaces after sanding.
Main Parts and Dimensions
The dimensions of the various parts are as follows in cm; part quantities in [ ]:
H = Height vertically, orientated from floor upwards (e.g. Leg Height 120 cm)
L = Length horizontally, orientated from left to right (e.g. Base Length 120 cm)
W = Width horizontally, from front to rear (e.g. Side Width 60 cm)
D = Depth or Thickness of wood (e.g. Base Support Front and Rear Depth 1.5 cm)
Base  - 120 L x 60 W x 1.8 D
Base Supports  Front and Rear - 120 L x 2 H x 1.5 D
Base Supports  Left and Right - 60 L x 2 H x 1.5 D
Legs  - 120 H x 12.5 W at widest point x 2.8 D
Sides  Left and Right 70 H x 60 W x 1.8 D
Height Adjustment Base Supports  (fit to the inside of the Sides] - 60 L x 7 H x 1.8 D
Frame Rails  1x Lower Front and 2x Rear - 120 L x 5 H x 2.8 D
Frame Rails  2x Upper Front - 35 L x 4.5 H x 2.8 D
Frame Gate Posts  Left and Right - 60 H x 4.5 W x 2.8 D
Frame Vertical Rails  (Front  and Rear ), excluding the Gate - 60 H x 3.5 W x 2.8 D
Gate Vertical Rails  - 55 H x 3.5 W x 2.8 D
Gate Vertical Posts  - 55 H x 4.5 W x 2.8 D
Gate Horizontal Rails  - 49.5 L x 4.5 H x 2.8 D
Blanks* for the Legs  - 120 H x 14 W x 2.8 D (cut from one piece of 120 H x 60 W x 2.8 D)
The leg design was inspired by the design of a bed available to buy online. I took one of the blanks* and drew the shape I wanted on it freehand with a pencil. When I was happy with the dimensions of the shape I used a band saw to cut out the shape as accurately and carefully as possible.Take care when using power tools like a band saw and sander and make sure you use appropriate Ear Defenders, Dust Mask and Safety Glasses/Goggles when using power tools! Safety always comes first! Isanded the whole leg with the hand sander and 120 grade paper until I was happy with the shape and finish. I then placed the finished leg on top of another blank, held it in place with a clamp and then traced around the shape with a pencil. I did the same with the other two blanks and then cut all three to shape using the band saw, again being as accurate and careful as possible.
I then put all four legs together so that they were all aligned with the straight (back) edge and used two clamps to hold them all together firmly. [Note about clamping - don't clamp directly to your nice wooden leg parts or you will probably leave a pressure mark or indentations on the surface of the legs. Instead, put a piece of wood in between the clamp and each leg you are going to clamp). Now using the hand sander I sanded the three legs until they matched the exact same shape as the first one. Now I have 4 legs all the same size and shape... :-) I un-clamped the clamps from the legs and then rounded the edges with the hand sander. Since this is a baby bed we don't want any sharp edges or corners at all (wherever possible).
Next, I sanded all four legs with the 180 grade sandpaper until they had a nice smooth and even finish all over and then painted them with 3 coats of the non-toxic, child compatible paint (white). You should ONLY use paint for a baby/child's bed which is officially approved for such use and which is clearly printed on the label. DO NOT use any other paint other than baby/child compatible paint. It is your responsibility as the builder to ensure the paint and materials used are safe for use with baby/child furniture.
Cutting and Sanding the Frame and Other Parts:
I cut all pieces to size using a circular table saw and then sanded them using a hand sander 180 grade sand paper. Since all of the wood was already finished with a reasonably smooth sanded surface out of the shop I only had to sand with one grade of sand paper for a good finish. If you use really raw wood you will have to consider sanding with 3-4 grades (80, 120 and 180) of sandpaper which will take more time and effort. Take care when using power tools like a circular saw and sander and make sure you use appropriate Ear Defenders, Dust Mask and Safety Glasses/Goggles when using power tools! Safety always comes first!
Step 2: Painting and Assembling of the Parts
Painting and Varnishing (Lacquer):
I painted all parts except the front parts of the bed and gate (see images) with 3 coats of the all-in-one baby/child safe white paint. The front parts and gate were varnished with 2 coats of baby/child safe all-in-one clear lacquer. I lightly sanded the painted lacquered surfaces with 180 grade sand paper in between the coats. This helps with adhesion as well as even coating of the substance. I am not a professional so the finish was not completely perfect like you would get from a retail manufactured or professionally made piece of furniture. I was happy with the finish I had achieved.
Assembly of the Parts:
I don't have any further images or an exploded diagram of the part-assembly, but I will assume that some of you have some experience in working with wood before. If you are completely new and have never built such a piece of furniture out of wood before, I would suggest getting someone who has some experience to help you.
Basically the first thing is to lay out the parts on the floor so that you can see which parts should be put together then drill holes in the ends of the rails with the 8mm bit to a depth of about 25mm and then drill holes on the other parts where those rails are going to be fixed. For the vertical rails at the front and rear, I used a spacing of 50mm between each vertical rail, which is a standard safety spacing for baby/child beds here and you should check the standard safety spacing for your country/region/state for such a baby bed - it is YOUR responsibility as the builder to ensure the minimum safety standards are met, please read about it or ask a professional for advice! You should check for other safety standards which may apply to the materials and building of such a baby/child bed depending on where you live - this is ultimately your responsibility as the builder as the design should always follow the region/state safety requirements. I have stressed this point, I know, but it is very important as I am not responsible for what you build and the safety standards per country, region or state.
For each of the  horizontal 120cm long rear Frame Rails and  horizontal 35cm short front Frame Rails to be used as part of the Frame I used 2x dowels and glue per end. The same applies to the  60cm high vertical front Frame Posts.
For each of the Vertical Rails to be used in between the Frame Rails I used 1x dowel and glue per end. Remember the 50mm spacing between each rail and the next.
For each of the four Legs I used 4x dowels and glue per leg and attached two of Legs to each of the two Sides (which could also be called the head-board and the foot-board).
The front and rear Base Supports were fixed to the front and rear horizontal Frame Rails using 3x stainless steel 4mm x 30mm screws by drilling holes through the face of the Base Supports with the 3mm drill bit and using the countersink bit for the diameter of this screw head (in my case 9mm).
The left and right side Base Supports were fixed to each of the two Sides using 2x stainless steel 4mm x 30mm screws by drilling holes through the face of the Base Supports with the 3mm drill bit and using the countersink bit for the diameter of this screw head (in my case 9mm).
This should complete the main frame and base supports of the bed.
Step 3: Fitting the Height-adjustable Base.
The Base was finished with 2 coats of approved baby/child safe all-in-one Clear Lacquer. Don't forget to sand the surfaces with 180 grade sand paper after the first coat and lightly sand all surfaces with the same sand paper after the second coat then wipe off with a damp clean cloth.
The height adjustable base requires the mounting of the two Height Adjustable Supports 60 x 7 x 1.8 using 3x stainless steel 4mm x 30mm screws by drilling holes through the face of the Height Adjustable Supports with the 3mm drill bit and using the countersink bit for the diameter of this screw head (in my case 9mm) and then screwing the Height Adjustable Supports to the Sides at the preferred height (in my case the top edge of each support was at 35 cm below the top edge of the Side). You may want to adjust the height according to your own preferences, but make sure that you are able to slide the Base in and out of the lower Base position easily without hindrance of the Height Adjustable Supports.
Note that I added a 25mm diameter hole to the middle of the front of the Base (edge of the hole is 10mm from the front edge of the base) so that the Base is more easily removable with one finger or thumb.
Please refer to the images for accurately fitting the parts together.
Step 4: Fitting the Front Rails and Gate
The assembly of the Front Rails is described in Step 2, above. Once you have assembled and fitted the Front Frame Vertical Rails with dowels and glue you should assemble the Gate with the Gate Horizontal Rails, Gate VerticalPosts and Gate Vertical Rails. The assembled Gate should then be attached to the Gate Frame Posts on the left or right using the two brass Hinges. The upper and lower Bolt assemblies should then be screwed to the Gate Posts and Gate Frame Posts as can be seen in the images (on the opposite side to the Hinges). This should be done so that the gate can be easily closed and opened to its full extent and that the Bolts are easily opened and closed. You may use a different mechanism for opening and closing the gate, but it MUST be baby/child safe and baby/child secure. The last thing, if required, is to add the name plate which I had prepared by a key-cutting shop.
If you have forgotten to glue something, go back and glue it now.
Step 5: The Finished Bed and Day Seat
With all of that done you should test the stability of the bed, to ensure that it is not going to fall apart over time and daily use. Ensure that the base fits snuggly into the base supports and that there is no 'play' or excessive free-space for the Base to move around which could be unsafe (this is very important!)
If you've finished all of that, you now have a completed baby/child's bed with adjustable height base!
Step 6: Special Notes and Tips.
Proven Design and Build Quality:
The image here shows the bed after 2.5 years of daily use (i.e. my daughter is now two and a half years old, we have moved house and she is still sleeping in it soundly). It has not fallen apart, she has not been able to damage it so far, despite her pulling and pushing the gate frequently. No injuries have occurred whatsoever from the bed construction and it was found to be a very easy system for access and closure from day one. The gate makes no sound when it is opened or closed, which helped with my daughter when we needed to transfer her to the bed already asleep.
2nd Bolt Assembly:
A second Bolt Assembly was mounted in a lower position on the Gate after about 1 year as we noticed just having the top bolt was not enough (my daughter started playing with the gate at the bottom whilst it was bolted shut at the top so we secured the bottom from opening using a second bolt). I have reflected this in the build steps of the Instructable so that the 2 Bolt Assemblies are mounted as standard.
My daughter ended up being one of those children who got teeth very early (actually 1 tooth already at 2 months old) and we found that she liked using them, more specifically she liked biting the wooden frame of the bed! Since we used soft wood and baby/child approved paint and lacquer there was no problem at all, just some marking (bite marks left on the frame of the bed and some marks where she chewed the paint off :-) You can't really know in advance if your child is going to be a biter...