For Walt Foti

 

Pikler Triangle

Emmi Pikler was a Hungarian Pediatrician who developed a theory of child development theory in the 1930s/40s. The concept was based on providing opportunities for the child to move freely and develop at their own pace.

Parents and caregivers don't put the child into any position they can't get into by themselves. It also means that caregivers should provide ample opportunity for the child to put themselves in positions to encourage self development.

It also means giving kids the opportunity to learn how their bodies can move (and climb) – hence the Pikler Triangle.

Design

Wood Selection and Milling

Hardware Choices

Sanding and Finish

Assembly

Final Product

 

Design

A Pikler Triangle for climbing...used this image somewhat as a prototype.

The unit must be safe, sturdy, portable, foldable, and easy to setup

My terminology...

long rack= one side consisting of 2 long legs, plus 6 rods

short rack = one side consisting of 2 short legs, plus 5 rods

two pivot plates connect the racks

First Sketchup model...

rough dimensions when setup for use...

width = 36 3/4 inches

depth = 33 1/2 inches

height = 44 5/8 inches

The two triangular pivot plates will be made of 3/4 inch red oak pywood, hope to find some quality EuroPly online.

The long rack will have two stile boards that will be milled from red oak planks.

They will be 1" thick by 3" wide by 48 "long.

Six 1 " dowel rods will be ~36" long, they will insert 5/8 inches deep into 1 inch drilled holes (every 8 inches).

 

 

The short rack will have two stile boards that will milled from red oak planks.

They will be 1" thick by 3" wide by 42" long.

Five 1 " dowel rods will be 36" long, they will insert 5/8 inches deep into 1 inch drilled holes (every 8 inches).

Second Sketchup..with some details fleshed out regarding the pivot plates...short legs extended two inches...

A pivot plate...3/4 inch plywood...four 3/4 inch x 1/8 inch deep countersinks for carriage bolts with through 5/16 holes...the three go into a long leg...the singleton is for the pivot bolt in the short leg.

The single 5/16 hole will accomodate the knob that secures the leg but removal allows the leg to pivot and then the entire unit is able to fold for storage.

There will be a slant board...it will be 3/4 inch red oak plywood, cut to 15.5" wide and 47.75" long.

It will be banded on the ends and sides with a 3/4 inch thick, one inch long piece of red oak.

The banding will be flush with one side...this being the slant-slide board side...(tinted pink in image)

 

The banding will stick up proud 1/4 inch on the slant-climb side...shown here tinted green.

This forms a light lip at the edges of the board.

The climbing strips are beveled slats that are 3/4" x 3/4 inch, chamfered edges...red oak...

There are five climbing strips plus the locking boards at the top.

The lock boards are red oak, 3/4 inch by one inch. They are spread to fit onto a one inch thick rod dowel.

The are chamfered for safety.

There are a pair of these lock boards on both sides...shown here tinted blue.

 

   
Wood Selection and Milling

My brother-in-law, Rusty, delivered up some red oak to me. This wood was milled on a farm in south MS and stored in a barn many years ago.

The wood is barn dry.

Boards were about 12 feet plus, 5 inch plus wide and 6/4 thick.

At the Benchmark table, Cindy and I cut them into 6 foot plus working blanks...

...and stored them to surface dry, it had rained the day they were delivered...

...then transported them into the shop.

Stored in the shop attic.

I was down to the last boards in my oak hoard...had to trash some pieces...

Took off irregularities at bandsaw before milling...

The coloration of some pieces was not very consistent...

example of boards after milling...jointed a face, jointed a square edge, planed to thickness and ripped a second edge...all of these boards are milled fat in thickness, width, and length to allow for further milling after boards de-wonk a bit.

Need eleven dowel rods...1 inch oak dowels x 36 inches long...

pricey but available at orange BORG...got 12 to have a CTD.

At the BORG I selected rods that rolled straight...they were somewhat irregular and certainly were not all the same length...I set up a stop at the chop saw and took off all of the ends...removing the painted ends...and guarantying a square end and a consistent length.

The most difficult task regarding the dowel rods was getting the labels off...they would not peel at all...soaked the labels in GooBeGone...

...and scraped off with the round edge of the 2001 tool.

Each dowel rod will slip into a 5/8" deep, one inch hole...centered in leg, one every eight inches...this hole will be drilled on the press with a one inch FAMAG Forstner bit.

The oak dowels have to be lightly sanded to fit.

After the large hole is drilled...a smaller twist bit (5/32) is used to drill a through hole in the center of the large hole.

 

Then a #6 x 1 inch square drive screw is countersunk from the reverse side...the drilling occurs after the rod dowel is in the hole...thus it centers the hole in the end of the dowel.

After the screws passes through the 3/8 inch thickness it will penetrate 5/8 inches into the dowel rod.

From the outer face side, the #6 screw is countersunk and will present no safety issues.

Working out the rounded end process...set up a CTD...The ends of each leg will have a 1.5 inch radius...laid out with a compass...

...cut fat with a jigsaw...

 

...stayed outside of the line...

and then finish sanded to the line at the oscillating sander.

 

I then chamfered all edges at the router table.

 

Hardware

Carriage Bolts

 

The pivot plates will be attached with 4 each 5/16-18 carriage bolts (3 will secure the long legs and 1 will be the pivot bolt on the short leg)...length will need to be ~1 1/2 inch.

The carriage bolt head will be slightly countersunk (~1/32 ") with 3/4 ZOBO Forstner.

This barely takes off the outer ply.

The center pointer clearly marks the wood.

Then a 3/32 inch twist bit is used to punch the center hole through onto the leg.

The 1/32 depth just allows the edge of the carriage bolt to be beneath the surface when pounded in...

The center point is then continued through just the leg to mark the center on the backside of the leg...this point locates the center of a 3/4 inch ZOBO...this hole is drilled to a depth of 1/2 inch.

 

 

Then a 5/16 hole is hole is drilled through at the center mark...

...on the backside of the legs... a washer and a nut must be countersunk below the surface for safety...(3/4 inch hole x 1/2 inch deep)

The thin wall of a 1/2 inch nut driver is a perfect fit to tighten the nut on the backside.

5 Star Handle & T-bolt

This is the handle that allows the unit to fold..

The star handle with a washer will be used to tighten the pivot plate.

On the face of the plate a 3/4 inch hole will be barely scored (~1/32") with a ZOBO bit.

Then a 3/32 hole is centered there and drilled through the 3/4 ply and into the leg.

 

Desired depth...the washer should be slightly proud of the surface of the plate...the handle should make contact only with washer.

A through hole (3/32) marks the center on the leg.

Then the 3/32 hole is extended through the leg showing the location of the T-bolt...a slot for the T is laid out marked

 

...and the countersink is made with Forstner bits and chisels.

 
   
   
Then a 5/16 through shaft is bored for the shaft of the T-bolt.  

...the slot holds the T end of the bolt in place.

The star handle and the washer allow the plate to be tightened.

For safety the T-bolt must not extend beyond the handle.

   
Sanding and Finish
Each rod was lightly hand sanded (150x) on the ends prior to assembly.
After assembly the rod dowels will be hand sanded ...with 220x paper.
 

Two coats of Amber Shellac, #pound number...

Rubbed on the legs and plates before assembly...on the rods after assembly.

 
Assembly
   

 

 

 

 

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