How to Make a Foldable Pikler Triangle (climbing Frame)

Emmi Pikler was a Hungarian Pediatrician who developed a new theory of child development in the 1930s/40s, based on allowing the child to move freely and develop at his or her own pace. (Magda Gerber, who founded RIE - the parenting philosophy to which we mostly subscribe - was Emmi Pikler's student.) In practice this means that parents and caregivers don't put the child into any position they can't get into by themselves - often a hard thing to do as a parent when you want to make sure your child meets the next official milestone 'on time.' It also means giving kids the opportunity to learn how their bodies can move (and climb) – hence the Pikler Triangle.

My 15 month-old daughter has attended a RIE playgroup for nine months now, and the Triangle is one of her favorite toys there so I knew I had to make one. I’m a member of some RIE-related Facebook groups and see requests every once in a while for instructions on how to build one so I took some photos as I went. I’m assuming that a lot of people making kids’ toys might not have a woodworking background (I’m somewhat of a novice myself) so my instructions are fairly detailed. The folding action definitely makes it more complicated; if you don’t need it to fold then you can just screw the Pivot Pieces onto the rails wherever you like and be done with it. Do let me know if anything isn’t clear and please post pictures of your finished projects!

If you're interested in Emmi Pikler's and Magda Gerber's approaches to parenting, you'll probably enjoy my podcast which you can find at www.yourparentingmojo.com - it examines scientific research related to child development through a lens of respectful parenting.

Step 1: Materials & Equipment

Materials

1. 12 feet of 2”x3” lumber - I used clear grain Douglas Fir. Buy a 12-footer, or get the lumber yard to cut a 12 footer in half so you can fit it in your car. Note that lumber is sold nominally, and 2”x3” lumber will actually measure a bit less than those dimensions.

2. 13 1” diameter dowels, each 3’ long. Check while you’re still at the lumber yard that the dowels are fairly straight – look down the ends and see if the dowel curves or just roll them on a flat surface. The Big Box stores particularly will try to sell you all kinds of crap wood so be sure to pick through it and get the best of what’s there. You might also take a caliper or tape measure to check the diameter. I ended up getting one dowel that was 7/8” in diameter which rattled around in my 1” hole and I had to take time out in the middle of the project to replace it. Grrrrr.

3. 2 feet of 1”x10” lumber (clear grain Douglas Fir again)

4. 2 stainless steel adjusting screws, 1” head size, ¼”-20 thread, 2 ½” screw length. (Production Tool Supply Part Number KHS-1SS– sadly McMaster Carr didn’t have anything that would work) I used the thumb screws and tee nuts as a locking mechanism because I couldn’t find any quick-release pins long enough to do the job. It’s not the most elegant solution because it takes a lot of screwing to collapse the Triangle for storage and then reassemble it, but it was the best option I could find. If you know of something better, be sure to let me know in the comments and I’ll update this info. Production Tool Supply has a $25 minimum so I ordered 4 thumb screws at $6.70 each – enough for two Triangles. You know someone is going to ask you to make one of these when they see it at your house so why not be prepared? Some of the other hardware also comes in packs that makes doubling up a sensible option; I’ll note that below.

5. #8, 3” screws (4 or 26, depending on whether you pick Option 7A or B) (McMaster Carr Part Number 90294A209, although you could likely get something similar more cheaply at your local hardware store)

6. 2 5/16”-18, 3” long stainless steel flat-head socket cap screw (McMaster Carr Part Number 90585A596) Sold singly.

7. 2 5/16-18 Nylon Lock Nuts (McMaster Carr Part Number 97135A220) Comes in a bag of 20. I got mine at the hardware store and they're 3/8" high; McMaster has 1/2" which will work fine.

8. 2 Steel ¼”-20 Internal Thread ½” barrel length Tee Nuts (McMaster Carr Part Number 90598A043) Comes in a bag of 50

9. Wood glue

10. Small amount of paint in one or more colors (if you want to paint it); I used some flat latex leftover from another project

11. Polyurethane – one quart (you won’t use much); I used semi-gloss but you could use gloss or flat if you prefer

12. Print-out of the two pdf template sheets for the Pivot Piece. Sorry I have neither the software or the skills to do this in some fancy drawing program, but I did trace around my wood piece for you...

Special Equipment

1. 1” forstner drill bit

2. 3/16" diameter allen wrench (no, none of those wrenches in that metric set you have will work). I got mine at my local hardware store.

3. 5/8" countersink bit

4. Long ruler or something straight you can use to draw a line

5. Compass

6. Circular saw, band saw, or jig saw

7. A drill press is very helpful although you could do it without if you are careful

8. A belt sander is very helpful although you could do it without if you have a lot of time and patience

Step 2: Cutting

Cut your lumber so you end up with two pieces each 36" long, and two pieces each 32” long. I got my three footers by cutting my six footers in half (it’s not critical if it’s an eighth of an inch or so off the measurement as long as the pieces are the same length).

The store-bought Triangles use dowels that are about 30” long so that’s how long I cut mine. If you wanted your Triangle to be wider for some reason you could just leave them at 36”. Most dowels are pretty low quality wood and they may have knots or other blemishes (or those darned stickers with the bar code that are really hard to dislodge). Try to cut off the blemishes if possible.

Step 3: Round the Ends of the Lumber

Measure the width of one of the flat sides of your lumber; a nominally 3” wide piece will actually be approximately 2 ½” wide. Put a small pencil mark at the end of your board at the half-way point. Set your compass to half of the length you measured and put it approximately centered between the sides and one end of your board. Check it all three ways and recenter the point of the compass if it’s off. Draw a semi-circle connecting the two sides and the bottom of the board. Repeat on the other end of the same board and also on the other three boards.

Use the saw of your choice (a band saw or jig saw would be fine) to cut along the semicircles you drew on all four pieces of lumber. It’s not critical to be exact, although if you don’t have a belt sander then getting a nice line with the band saw will save you a lot of time.

Set up your belt sander – I like to tip it upside down and clamp it to my sawhorse. I then install an 80 grit belt and set the sander to run continuously on Speed 4 (of 5), which allows me a bit flexibility in shaping; the sander can really remove a lot of material quickly at full speed and sometimes you lose more than you’d planned. Sand around the curve a bit, then check and see whether you’ve sanded up to the line you drew, that both sides look similar, and that the curve from front to back is roughly flat. Keep sanding and checking until you’re happy with the result.

Step 4: More Sanding

When all of your ends are nicely shaped, switch to a 120 or 150 grit belt and smooth out any nicks or marks on the flat surfaces of the lumber. Make sure to keep the entire width of the lumber on the belt at any time or the belt will dig a rut into the wood that is time-consuming to get out.

While you still have the sander out, unclamp it from your sawhorse and find the 1x10 board. Sand it lightly to remove any blemishes, being careful to move the sander in a kind of W shape, mostly moving up and down the length but also across as well so the belt doesn’t dig a rut in the wood.

Use a piece of sandpaper cupped in your hand to smooth out the dowels, and also rub off any excessive roughness from the cut ends of the dowels.

Step 5: Cutting Holes in the Side Rails

Inspect each piece of lumber and decide which are the “nicer” sides and ends (better shaping; better grain pattern/color, etc.). I usually put the nice sides out and the nice ends up.

Measure half way across the width of each of the INSIDES your long pieces of lumber and LIGHTLY (makes it easier to sand it off later) draw a long line at this point down the length.

Now take the long side rails and put an X every 5” where your dowels will go (make the Xs big and heavy enough to see; you’ll cut them out in the next step). You likely lost a bit of length when you were sanding so put the first X 1” below whichever end you decided was the top, and let the rest fall out every 5” from there. It’s not a big deal if the bottom rung is a tiny bit less than 5” from the floor. Repeat on the other long rail.

Measure the distance of the bottom rung on the long rails from the floor, and put your first X on the short rail that same distance from the floor with the rest every 5” from there. Your top X should be about 2” from the top of the board (you don’t want it to be much less than that because you need room above it to install the bolt). Repeat with the second short side rail.

Set the depth stop on your drill press so the forstner bit will penetrate approximately half way through the thickness of the board. If you don’t have a drill press you could put a piece of tape on the bit at the right depth; you’ll have to keep stopping the drill to see if the tape is lined up with the top of the board.

Drill a hole into each X, being as careful as you can to get right on the X (I found that when my bit was spinning I could actually look ‘through’ it to see the point touch the X) until you hit the depth stop. Repeat with all Xs on all four side rails. Check the depth of your first and last holes to be sure they are the same (she says from bitter experience).

Sand out the lines that you drew down the middle of the boards (aren’t you glad you did it lightly?).

Wipe your pieces down with a clean rag to remove sawdust and then vacuum so if you drop a piece while painting it won’t come up covered in sawdust.

Step 6: (Optional): Paint

My husband has a thing about ‘pops’ of color, and also about odd numbers. So I had to paint an odd number of rungs in bright colors – he would probably have preferred that I get three custom colors just for this but instead I used paints I had left over from other projects.

Balance however many dowels you choose to paint across the sawhorses, leaving the ends floating. Put a THIN coat of paint on the ends - if too much paint builds up you won’t be able to get them in the holes. On my prototype I skipped this step thinking I could just carefully edge around the side rails – BAD IDEA. When your ends are dry, switch to balancing the rungs on their ends and put two coats on the middles (up to about 1/2” from the ends).

If you’re going to paint your whole ladder then you can skip this step and instead paint it before polyurethaning.

Step 7: Assembling the Ladders

Do a dry fitting to make sure your dowels all fit in the holes. Some of my dowels needed sanding to fit and one was 1/8” too narrow and had to be replaced so it wouldn’t rattle around in the hole. Ideally the dowels will lift easily in and out but a tight fit is OK as long as the dowel does go all the way to the bottom of the hole on the dry fitting as the glue will lube things up.

You have two options here.

Option A:

For my prototype I came up with what I thought was a pretty nifty method to screw the dowels into the side rails. I think that’s probably actually overkill as most of the Triangles I’ve seen since are just glued, so my official method is glueing only. But if you want the extra security – maybe you have very heavy kids? – use my screw method. Take a 1/8” drill bit and drill straight through the middle of the holes that you made for each dowel, using the divot that the forstner bit made as your guide. Drill all the holes now (don’t try to fit dowels in some and then drill the rest later). Now put a dowel into each hole and tip the whole lot over so the unit is standing on the dowels on the floor and the side rail faces up. Here’s the nifty part: the hole you just drilled becomes a little doweling jig and allows you to drill a pilot hole straight down into the dowel with no further equipment or support needed. I drilled 26 of those things and didn’t pop out the side of the dowel once. Neat, huh? Pilot all of the holes, and then screw a screw into each pilot on both ladders hole EXCEPT the top TWO holes on each side rail of the long ladder.

Official Option B:

As described in Option A, drill a pilot hole through the divot left by the forstner bit in the two holes at the top of each of your long side rails ONLY (so, four holes total). You’ll use these holes to attach the long ladders to the Pivot Pieces.

Put a small amount of wood glue into each of the holes on one long side rail. Use your finger to spread the glue up the sides of the hole, which will help provide lubrication in case any of your dowels are a tight fit. Place a dowel in each hole and hammer each one with a rubber mallet to seat them. Working quickly, glue each of the holes on the other side rail of the same length. Make sure the tops of your side rails are facing the same way. Place the second side rail over the dowels, coaxing them into the holes. When they’re all positioned correctly, bang on the side rail with a rubber mallet to seat the dowels.

Whichever method you used, complete the short ladder in the same way, except that you screw into all holes if you used the screw method. Put a mark for the bolt about half way between the top of the top dowel and the top of each of the short side rails (that’s a lot of tops).

Step 8: Cutting the Pivot Pieces

Cut out and assemble the Pivot Piece template, ensuring that the check lines all measure 1”. (I didn't want to assume that you had access to anything other than a cheap household printer; sorry that this requires assembly of the template pieces.)

If the 1x10 board has nicer sides/edges, put the nice side up toward you and the nice edge down toward you. Align the bottom of the template with the bottom of the board and either draw around it or use a light tack spray to hold it on the board (just spray the template, not the wood, and allow it to dry before positioning so you don’t get paper welded to your board). Use the point of a screw or drill bit to poke through and mark the holes labeled A and B ONLY (do this first in case the template comes loose during cutting), and then use the band saw to cut out the shape.

Check for fit by aligning the Pivot Piece with one of the long side rails (the end with the holes in). Do the contours of the Pivot Piece follow the side rail? Does it look like the hole markers are centered over the dowels? Trim as needed (but make sure it REALLY is needed before you trim). When you think it’ll work, sand your cut and knock the corners off the edges with some sandpaper cupped in your hand. Put a 1/8” pilot hole through the marked holes in the Pivot Piece and use your countersink bit to make a small divot for the screw heads to sit in.

Drill with the 1/8” bit into each of the four holes in the long side rails to put a pilot hole as far into the dowels as you can.

Repeat with the second Pivot Piece, this time cutting holes B and C only.

Step 9: Polyurethane

Put at least 3 coats of polyurethane on the two ladders and on the Pivot Piece. This can be time-consuming because of all the nooks and crannies. After you finish a coat, go back over it again and brush away any drips. I suppose you could suspend each ladder from the ceiling and do a complete coat at once; if you lay it down you generally have to flip it back and forth from one side to the other to complete half a coat at a time.

Step 10: Final Assembly (AKA the Moment of Truth)

Screw the Pivot Piece to one of the long side rails through the two holes. I set the screws so they're just sticking out of the bottom of the pivot piece, which helps me to locate the holes in the side rail. When the screws are in it should feel pretty solid. Do the same with the other Pivot Piece on the other side of the long ladder.

Bolt Placement

Set the long ladder down so one Pivot Piece is on the floor and the other is parallel to the floor. Slide some spacers (left wood from cutting out the Pivot Pieces) – one under the Pivot Piece and two under the side rail of the ladder.

Now slide the short ladder between the two Pivot Pieces, adjusting so the side rail is parallel to the side of the Pivot Piece, and the top rails on each ladder are 5” apart on center (i.e. from dowel center to dowel center, not dowel edge to dowel edge). Drill a hole with a 21/64 bit (11/32 will do if you have that instead) for the bolt through the ladder side rail and also through the pivot piece at the marked spot. Ease the drill bit in gently toward the end to avoid splintering on the Pivot Piece. (Stop when you feel air followed by concrete...)

Flip the unit over and countersink the hole on the pivot piece side only (no need to countersink the side rail). Slip a bolt into the hole and install a locking nut. You want the locking nut to stop 1/16” or so from the side rail so it holds the pieces firmly but doesn’t restrict the swinging action. Now line up the second side of the short ladder in the same way that you did the first and make another bolt hole and install the second bolt.

Screw Placement

Place the Triangle back on the floor in its ‘braced’ position and pick a point below the second rail *where you’ll still hit the Pivot Piece when you drill through* and drill a hole with a 9/32 bit through the side rail and Pivot Piece. Exact placement is not critical as long as you go through the Pivot Piece at some point, but I put mine half way between the top two rails. Again, ease the bit in gently to avoid splintering on the Pivot Piece. If you do get splinters (as I did) you'll have to trim them with a chisel as you won't countersink this hole. Now take a 11/32 bit and enlarge the hole in the side rail to a depth of ~3/4” to accommodate the tee nut. Exact depth is not critical but make it somewhere between the depth of the tee nut and the width of the side rail. Flip the unit over and do the same on the other side.

Insert a tee nut into each of the holes in the side rails and tap them down with a hammer if needed. Screw the thumb screw in from the outside of the Pivot Piece. It does take a fair bit of screwing to seat it but it does the job.

That’s it! Enjoy your new Pikler Triangle and please share photos of your projects.