Introduction: Monkey Bars
For a while I've really wanted to make some monkey bars for my daughter who is crazy about them at the moment. It was a great school holiday project (meaning she got to help out) and who doesn’t love monkey bars?
After searching the Instructables site (my normal go-to) and not really finding what I was after (which is unusual), I decided to design my own. There are a few things I would do differently but this was basically my process.
Note: this is my first attempt at writing an Instructable so apologies for any lack of clarity in the instructions.
- 6 x 2600mm lengths of 45x75mm structural pine
- Screws (galvanised) 75mm
- Screws (galvanised) 20mm
- 2 x 1800mm oak dowel (25.4mm diameter)
- Two lengths of 20mm hardwood (70mm x 1000mm)
- 8 x L brackets
- Paint (exterior)
- Oil for waterproofing
- Mitre saw (or if you're brave, a good sharp hand saw)
- Cordless drill (pillar drill would be good)
- Drill bits (I used a 3mm but it will depend on your screws)
- 25mm core bit (see improvements)
- Belt sander
- Vice (you could use clamps)
- Sanding block/sandpaper
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Step 1: Finalise the Design
I had an idea in my head about what I wanted the end product to look like but no plan to work from so I sketched out a few ideas. I went for angled legs to make it more stable as it was going to be a stand-alone set of monkey bars. The height required I roughly guessed from the monkey bars at my daughter’s school and the width between the bars I estimated. After a few rough sketches, this is what I ended up with.
Step 2: Marking Out
I kew I wanted to make the top section first, then add the legs.
The sides of the top are made from two of the 2600mm lengths of pine and the first step was to figure out the spacing of the rungs, so I would know where to drill.
I found the mid point of my 2600mm pine length, then marked up where my six monkey bar intervals were going to go. This was a bit trial and error as I was sort of making it up as I went. I knew that I wanted the legs to anchor on not at the very edge because I needed to brace these. In the end, I worked out a distance of 400mm between each bar, with 300mm clearance from the end.
Step 3: Drill
Making those dowel fit snugly was always going to be the major challenge so I bought a 25mm drill bit specially for this job. Unfortunately, I bought a speedbore bit which was quite frankly terrifying. At first I tried my pillar drill (ideal for more accurate cuts) but the speedbore sank into the wood far too quickly and just jammed up every time, regardless of how much I tried to control it. I ended up just clamping the timber in my vice and using a cordless drill for this part (see picture). In hindsight, I should have gone and swapped the bit for a spade bit and used the pillar drill.
Step 4: Sanding the Dowel
So I had my 25mm hole and a 25.4mm dowel to fit inside it. After spending some time hand sanding the ends of the dowel trying to shave that last .4mm off (see picture one), I decided to get a bit more technical and clamped my belt sander in my vice. I then held the dowel against the running belt until enough was shaved off evenly (I held it loosely in my fingers which allowed it to spin slowly but still take some off - see picture two). I worked my way through all six dowels, testing them in the pre-drilled holes as I went to make sure I ended up with a snug fit so the monkey bars wouldn't rotate in the wood.
Step 5: Assembly
Grab your mallet!
With the sanding was complete, I placed each dowel into a hole, then, using an off-cut of pine to protect the end, used a mallet to bang the dowel into the pine until it was flush. Doing all six dowels on one side first, then adding the other side and repeating. This created a ladder like shape which I suspended between two sets of shelving in the garage and hung off each rung to strength test it.
Step 6: Cutting the Legs
I cut 4 x my remaining pine lengths down to 1600mm on my mitre saw knowing that was roughly the height I wanted, reserving the 1000mmm offcuts.
I knew that in having angled legs, I'd need an angled cut on the top and bottom of each leg to secure it to a horizontal baseboard. After attempting to calculate angles for the legs using trigonometry, I gave up and decided a more practical method would be quicker (and easier than trying to remember something I haven't used in 20 years). Unfortunately, I didn't take any pictures of this part so you just get my awful drawing but hopefully that and the below description makes it clear.
To figure out the angle of the cut, I lay my ‘ladder’ on its side and placed one 1600mm length square against the end, creating a right angle (see awful drawing). This showed me where the leg would need to end. I then took a second 1600mm length and put one side on top of the first one with the other on top of the ladder frame, creating a triangle.
This showed me the angle I needed to cut the timber at. I marked this with a pencil.
Step 7: Cut the Legs!
I adjusted the angle on my Mitre saw using the laser to match the angle I’d created in Step 6 (picture 1 shows the angle against a square piece of pine). If your saw doesn't have a laser, I guess you're back to ninth grade trigonometry.
I cut all four legs to size, cutting the bottoms at the same angle to ensure they’d be level with the ground, and the top so that they'd end up flush with the top of the 'ladder'.
Tip: be careful when you're making your cuts to ensure both ends are cut in parallel (see picture 2) or you’ll end up having to do this all over again like I did (whoops). After cutting, I placed the leg against the frame to make sure the proportions seemed right (picture 3).
Step 8: Secure the Legs
I toyed with screwing through to the 'ladder' to keep the timber flush (see picture 1) but quickly dismissed that idea, realising that screwing outside would give a bit more clearance as well as making it more secure.
With some help from my daughter at the other end, I got my first leg in place onto a stool, then drilled the guiding holes (x 2) through the leg. Switching for a Phillips head bit, I screwed the legs into the ‘ladder’ frame. Repeat for all 4 legs.
Step 9: Adding Steps
I have two daughters and wanted the younger one to be able to use it as well so I needed to put a couple of steps in so the little one could reach. This also helped to make the structure more secure. I cut 4 x 590mm from the leftover 1000mmm and marked out where I wanted the steps to go (bottom of the riser ended up at 220mm off the ground then 330mm. You can adjust this to whatever you like though. I held the wood in place with clamps, drilled and screwed one screw into both sides, then levelled it out and finished with the second screw.
Step 10: Adding a Base Board
For $20 I picked up two fairly rough cut pieces of Blackbutt timber from my local scrap yard (Urban Salvage in Spotswood which is amazing). This part really helped to make everything come together. The weight of the hardwood holds the monkey bars down and just secures everything laterally.
I used some L-brackets to secure them. To do so, I measured so they’d be centred, pre-drilled and screwed these in using the 20mm screws (four in each part of the L bracket). Make sure you mark out and pre-drill BOTH sides of the base board at the same time - it is much trickier to do this when the legs are attached.
Step 11: Bracing
At this stage, my monkey bars were laterally quite strong but there was still a bit more flex than I was hoping for along the length so I needed to brace the legs. After a few sketches, tests and flirtations with half-lap joints, I decided simplicity was best way forward. I cut the remaining 400mm (leftover from step 9) in half using a 45 degree cut on my mitre saw. This gave me two pieces that I could brace either side of the leg. I secured these using 75mm screws (though I ran short by two screws in the end and used a couple 80mm screws I had lying around).
The process for this was to clamp the brace against the ladder to hold it in place, with the 45 degree cut side flush against the leg (see first picture), then drill and screw this in place, with two more going into the leg at different angles (see second picture). This worked really well. The process was simple but the flex was all but eliminated by this.
Step 12: Sand Sand Sand Then Paint (optional)
The pine I bought was a bit rough in places so I used a block sander of 120 and 220 grit to smooth off the edges. I had some white exterior paint lying around so I ended up painting it in that to make sure it was waterproof. I put some outdoor furniture oil on the dowel as I wanted to retain the timber look on the rungs.
Step 13: Finished!
My monkey bars were done! The girls love them and I've put them on some soft grass so any falls are pretty well cushioned. You could put mats underneath if you only had hard floors etc. I'm thinking about adding another piece and creating a modular ninja warrior course for them!
So, what I would change?
- The speedbore bit was a nightmare. Would definitely swap for a spade bit or other kind.
- Sanding everything beforehand would have been helpful (as would having a full design!)
- I had planned to drill and screw down through the timber into the dowel to secure it in place. This proved unnecessary because when I used the mallet to knock the dowels into place, they ended up snug and secure (though I may need to do so depending on how it wears).
- I would consider moving the legs back a little bit towards the edge of the frame. This would allow more gap between the starting position and the first rung. It’s a small issue though and they’re perfectly functional.
- The white paint looks good but I'm going to repaint the rungs and baseboards a charcoal colour because they're getting muddy and don't look great.