Introduction: Ajustable Plinth for Parkour / Freerunning

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3D model : https://goo.gl/2i3GUQ

Français : https://www.instructables.com/id/Plinth-D%C3%A9mo...

Every sport requires practice and parkour is no exception. On the other hand, you cannot always go in the city or in a gym to train, and owning the necessary accessories for this training is then essential. A gymnastics plinth can cost approximately $1000, which is a rather important investment, but this guide can show you how to make one yourself for about $150 (the price can vary depending on the price of the materials).

Dimensions :

Width : 4'
Depth : 3' 6"
Height : 4' (4 levels), 3' 3 1⁄2" (3 levels), 1' 11 1⁄2" (2 levels), 8" (1 level)

Weigh per level :
1 : 24.3 lbs
2 : 39.7 lbs
3 : 45.2 lbs
4 : 22 lbs

Necessary equipment:

  • Protective gloves and glasses
  • Drill
  • Reclining circular saw
  • Wood drill bit (5/64", 3/32", 7/64" or 1/8")
  • Countersink drill bit
  • Hole saw (1 1⁄2")
  • Sand paper (and an electric sander if possible)
  • Wood glue
  • Clamps (2 if possible)
  • Tape measure
  • Level
  • Workbench (or table to put the plywood when sawing it)

IMPORTANT : Fully read every step before completing it, because some details are written at the end of every step.

Step 1: Materials

For this plinth, you will need :

  • 2x 4' x 8' x 3/4" plywood panes (outdoor treated if possible)
  • 6x 2' x 2' x 8" lumber
  • 2x boxes of 100 2" screws
  • 6x 12" straps (See picture)

Step 2: Tracing

Once the materials are bought, you need to trace the different cuts onto the plywood and the 2x2s.

See the pictures for the tracing.
First measure and trace the lines on the wood, then write the names of the different pieces (on the plywood) and write the length on the 2x2s, there are large ones of 426 mm, medium ones of 313 mm and small ones of 213 mm, besides the trapezoidal ones (2 large ones and 2 small ones).

On the plywood, the measures are done with 1 m 20, but you can leave the full width (4 feet) for the rectangles (A, B, C and D). You do have, on the other hand, to respect the measurements for the trapeziums (E, F, G and H).

Advice:
Write if the cut is an angled one or if it's straight next to each cut.

IMPORTANT :
- Include the width of the saw blade, otherwise the plinth won't be straight and you'll have to sand more (see picture).

Step 3: Sawing

Now that everything's traced, it's sawing time!

It would be better to be two for this step.

Saw the plywood and the 2x2s following the tracing. The second person is going to hold the pieces of plywood while the first one is sawing to prevent them to break under their own weight.

When the sawing is done, place every piece in group by level (all the pieces of the first level, all the pieces for the second one, etc.)

To make straighter cuts, take a long wooden slat or a straight long wooden or metal piece that you're going to hold with clamps on the plywood. That way, you can rest the saw on this guide to saw in a straight line.

IMPORTANT :
- Some cuts are done with an angle, which are shown on the plan.

Step 4: The Handles

With a 1 1/2" hole saw, drill the holes on the upper and lower end of the pieces F and G, the lower end of the pieces E and the upper end of the pieces H (see picture) : measure and trace the vertical middle of each trapezium and trace a line at 4 cm of the edge, then make a mark at 5 cm of the middle, on the line (the center of the two holes will then be 10 cm apart). Place the wick of the hole saw on the mark and drill the holes, placing a piece of wood under the plywood, where you're going to drill the hole.

To be more efficient drilling the holes, slightly raise and push the drill into the wood, in the manner of a jigsaw, but slower.

This step can need a more powerful drill if you have one, I personally used a wired drill for this step.

WARNING : the hole saw is going to get burning hot and it will require wearing thick gloves for manipulation.

Step 5: Assembling the Levels - 1

Now that everything is ready, it's time to put together the levels. Steps 5 and 6 will be repeated for all the levels.

First, you have to screw the corner 2x2s on the trapeziums.

  1. Take the 2x2s, put glue wherever there will be contact with the trapezium, then place it on the trapezium, aligning the bottom and put the clamps.
  2. Drill the plywood (5 holes for levels 2 and 3, and 3 holes for levels 1 and 4).
  3. Countersink the holes.
  4. Screw the plywood to the 2x2.
  5. Repeat for the other trapezium of the same level.

IMPORTANT :
- Align the bottom of the pieces so that you'll have only the top to sand. This will help for the stability too.

Step 6: Assembling the Levels - 2

Once the 2 trapeziums are completed, you have to screw the side pane.

  1. Take a trapezium and one of the panes, put glue on the 2x2 and place the pane on it. Use the clamps.
  2. Drill the plywood (5 holes for levels 2 and 3 and 3 holes for levels 1 and 4), countersink the holes and screw the plywood to the 2x2.
  3. Repeat points 1. and 2. for the second trapezium, then for the second pane.

IMPORTANT :
- Make sure that the pane is in the right direction before putting it on the 2x2 (see picture)
- Make sure that the screws are slightly offset and don't collide in the trapezium's screws.

Step 7: Sanding

Once the levels are complete, they'll need some sanding pretty much everywhere to make sure that every level rests on the entirety of the surface of the inferior level.

With an electric sander or sandpaper and a lot of patience, sand the corners where some parts go past the others (see picture). Once this is done, take a level and straighten the panes (not with the level's bubble, since the ground may not be straight, but with the straight side of the level). Then, place every level on the inferior level and look where you have to remove matter to make everything fit together.

Step 8: The Horizontal Pane

Now you have to put the pane on top of the plinth.

  1. Measure the middle of the length and mark it.
  2. Put the 2x2s on the middle marks (put glue on the surface of contact between the 2x2 and the plywood, put the clamps on, drill 3 holes, countersink and screw).
  3. Put glue on top of the 6 2x2s (where the top pane will sit), then place the pane on the level, aligning it by length and by width.
  4. Paying attention not to make the pane move, drill vertically the plywood 6 times (1 hole per 2x2), then countersink and screw.

IMPORTANT :
- make sure that the 2x2 are well aligned with the TOP of the level, since the pane on top must be straight.

Step 9: The Wedges

This step concerns only the levels, 2, 3 and 4.

For the levels to fit in one another, you have to put wedges in the corners. For the levels 2 and 3, the 2x2s are the same length than the corner ones, except that they are offset 10 cm and for the level 4, it's the 313 cm 2x2 that you will use.

  1. Measure 10 cm from the bottom of every corner 2x2 and trace a line. (ignore this very step for the level 4)
  2. Put glue on the 2x2 and on the plywood where the wedge will be placed, then put the wedge in its place.
  3. Drill the wedge in the direction of the corner 2x2 (3 holes for the levels 2 and 3 and 2 holes for the level 4), then screw the wedge to the corner 2x2 (you don't have to countersink because the 2x2s are soft enough for the screw head to fit in).
  4. Repeat the points 1. 2. and 3. for the 3 other wedges.

Once the 4 wedges are put, take the superior level and put it on it to see if it fits. If it doesn't (for example, if the wedges of the inferior level are too wide compared to the superior level), maybe you will have to sand the wedges a bit to make it fit. Rub some candle wax on the wedges : it will help to make it fit better.

Repeat for levels 3 and 4.

Step 10: The Reinforcements

This step only concerns the levels 2 and 3.

To help the solidity of the sides of the plinth, you have to put horizontal reinforcements to the levels 2 and 3 (the level 1 doesn't need it because of the middle 2x2s and the level 4 either, because it won't be used to give an impulsion on it's side with your foot).

  1. Measure the thirds on the length of the level and trace them.
  2. Put glue on the two ends of one of the reinforcements and put it in line with one of the marks.
  3. Drill the plywood in the length of the reinforcement (1 hole each side), countersink and screw.
  4. Repeat the points 1. 2. and 3. for the second reinforcement.
  5. Repeat the points 1. 2. 3. and 4. for the level 3.

IMPORTANT :

- Make sure that you use the good 2x2s for each level : the reinforcement should come approximately to the half of the height of the level when it's straight.

Step 11: The Finishing

Now that the plinth is done, you have to sand some places to avoid being hurt.

  • Every hole must be sanded on the inside and the outside
  • The corners and the sides of the top pane must be sanded

Step 12: Tying the Levels With the Straps

To tie the levels together, you have to use small lashing straps (cheap on Amazon or aliExpress)

  1. First, pass the head of the strap from bottom to top in the holes on the right.
  2. Then, pass the other end of the strap from top to bottom in in the left holes.
  3. Pass the strap inside its head and tighten it by pulling in the opposite direction of the head (in the bottom left).