49_06_plyo_boxes.pdf

CrossFit Journal Article Reprint. First Published in CrossFit Journal Issue 49 - September 2006

Plyo Box with Slanted Sides

Lincoln Brigham

Plyo boxes are very popular in CrossFit gyms. They’re

great for all kinds of workouts—or for just sitting on

after a good workout with your head cradled in your

hands waiting for the room to stop spinning. However,

commercial plyo boxes can cost as much as $100 to $200

each, plus shipping. Homebuilt equipment—a favorite

CrossFit brand—can be constructed with quality at

least equal to that of the best commercial designs and

at significantly lower cost. Square boxes and open-sided

boxes take a bigger toll on the shins from missed jumps,

and slant-sided boxes are stackable, so they require less

floor space for storage. So this month’s journal brings

you the do-it-yourself CrossFit custom plyo box with

slanted sides. Your friends, relations, workout buddies,

and clients will be sore impressed! Or just plain sore

after a hard workout on one of these babies. Total

cost for this project should be in the neighborhood of

$40-60 per box or less, depending on the size and your

bargain-shopping abilities

Cardboard mock-up

The first step is to use the instructions below to build

a mock-up of the plyo box with the cardboard and

packing tape. Really. Trust me on this. it’s worth the

time. With a cardboard mock-up, these plans can easily

be adapted to any size plyo box desired. Additionally,

building the cardboard mock-up saves a lot of tedious

measurement calculations and head scratching, and it

serves as good practice for measuring and assembly

before cutting into expensive plywood. As carpenters

always say, “Measure twice, cut once.”

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Plyo Boxes (continued...)

(left) a cardboard mockup helps make sure the box is the right size for your application. (right) how to make the most of your plywood.

Materials

5 sheets of 24” x 20” cardboard

Packing tape

4’ x 8’ x 3/4” maple, oak, or birch plywood, 1.5

sheets per two large 20” boxes (Skimping

with cheap or thinner plywood is not worth

the savings. And don’t even think about using

particle board.)

18” x 18” rubber mats, one per plyo box

(try the local feed & grain supply store)

1-1/4” drywall screws, 40 per plyo box

Wood glue

Contact cement, 1 pint

Base paint (primer paint for use on wood)

Semi-gloss colored paint

Semi-gloss polyurethane varnish

Bumper sticker from CafePress.com

base and 17.5” square top, but you can scale them to

whatever size boxes you want.

You can also make the angle of the slope as steep as

you like, bearing in mind that assembly and cutting gets

trickier, and stability decreases, as the angle increases.

This project uses approximately a 10-degree slope. If

you are not comfortable with woodworking and cutting

wood at an angle, you can make the box with straight

sides.

Each side of this box will be 23.5” wide at the bottom

and 17.5” at the top. Always remember that the plywood

is 3/4” thick. This means that two of the sides will have

Equipment

24” straight-edge ruler

Table saw or circular saw

Variable-speed drill with screwdriver bit

Jig saw

Utility knife, carpet knife, or box cutters

Sander with both coarse-grit sandpaper and extra-

fine-grit sandpaper

Safety goggles

Instructions

These instructions are specifically for making a pair of

boxes that are approximately 20” high, 23.5” square

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Plyo Boxes (continued...)

these dimensions and two will be cut 1.5”

narrower: 22” at the base and 16” at the top.

Draw a 3/4” edge on the cardboard mock-

up to get a good visual on this.

Use the cardboard mock-up and the ruler

to lay out the patterns to be cut on the

plywood. The sides for two boxes can be

cut using just one sheet of plywood if the

base of the box is 23.5” or less. Be sure to

leave about 1/4” between cuts to allow for

the width of the saw blade!

Now begin the cutting. The top and bottom

edges will be cut at an angle so that the top

sits flat on the sides and the whole thing sits

flat on the ground. Set the saw blade angle

by eye using the cardboard mock-up as a

visual guide. The angle is not super critical,

just be sure that you cut the top and bottom

edges at angles parallel to each other. If idea

of parallel angles sends you back to horrible

memories of ninth-grade geometry, simply

make sure that you start the long cuts from

the same end of the plywood each time.

Using the layout picture, make the four rip

cuts (i.e., the long way) with the blade set at

an angle. Then set the saw blade back to 90

degrees to finish the rest of the cuts.

Do not try to cheat by using square cuts for

the top and bottom edges. This will result in

a box that is difficult to assemble and finish

as well as significantly weaker. Again, if you

are not comfortable with angled cuts, build

a box with straight sides. You may scrape

more skin off your shins with straight sides,

but at least you won’t tear your hair out trying to screw

the box together, and the box won’t collapse when

Trainee Ted the Tort Attorney jumps on it.

Pre-drill holes for the screws 3/8” from the sides of

the two wider pieces Glue and screw the box together,

using the packing tape or a helpful friend to hold the box

together while you screw down the pieces. Don’t use

nails instead of screws; that’s just asking for trouble.

Be sure to make angle cuts for the

top and bottom edges of the side

pieces to ensure snug, strong corners

when assembled (top left). If you’re

not fully confident in the strength

of the corners, some bracing can

be added (top right). Use screws

to assemble the boxes, not nails

(bottom left).

angle as the sides, pre-drill screw holes at a slight angle

3/8” from all four edges of the top, and glue and screw

the top into place.

If the joints are nice and tight, no further bracing should

be necessary. If you are nervous about your carpentry

skills, additional internal bracing in the corners may be

helpful.

Next, draw outlines of handle holes on two opposite

sides of each box. Drill a starter hole for the jig saw in

the middle of the handle area. Make the hole big enough

for the saw blade. Cut the hole for the handle slowly,

being careful to rein in your great CrossFit strength to

avoid twisting, tilting, or snapping the saw blade.

Glue & screw = strength and durability

Turn the box upside down onto the remaining plywood.

Use the assembled box as a guide for the measurements

for the top. Cut the top so the edges are at the same

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Plyo Boxes (continued...)

Sand the edges and joints smooth with coarse sandpaper,

especially the edges of the handle holes. Use wood

putty if necessary to hide any gaps. Paint the sides—but

not the top—of the box with a base coat. (Warning: if

you don’t use a base coat, you’ll need at least 4 coats of

color.) Let dry according to directions on the paint can,

then finish painting with a coat of semi-gloss color of

your choice. After the paint has dried, apply 2-3 coats

of polyurethane with fine sanding in between coats. Do

not paint the top!

Sand the top of the box to remove any stray paint.

(You didn’t paint the top, did you? If you did, sand it off!

Contact cement won’t hold on paint.) Cut the rubber

mat to size with a utility knife. Again, angled cuts that

continue the slope of the sides will look more profes-

sional. Apply one coat of contact cement to the bottom

of the mat and one coat to the top of the box. Let dry

for 15 minutes before assembling. Contact cement is

strong as heck but tricky to work with—you’ll get only

one shot at assembly and then it’s stuck for good, so

align the mat with the box carefully before actually

setting it on. Be sure to let the contact cement dry until

tacky before applying the mat. Use a hammer on the

mat to ensure full contact. If done correctly, the contact

cement will be stronger than the plywood.

If you plan on stacking the boxes, glue a 4” x 4” piece of

leftover rubber mat or plywood to the underside of the

top. This will keep the boxes from sticking together.

For a slick custom look, you can create a custom bumper

sticker online to use as a label for the box. It’s only $3

plus shipping. If the logo has a distinct border, a nice

visual touch would be to carefully cut along the border

with a sharp knife before removing the backing. This will

make the logo look less like a bumper sticker and more

like a custom logo

Down and Dirty

Bombproof Low

Plyo Boxes/Pulling

Blocks

Materials

18 feet of 2” x

10” lumber

(actual board

dimensions 1.5”

x 9-3/4”)

60 long drywall

screws

Wood glue

Equipment

Saw

Screwdriver (variable speed drill would be very

helpful)

Instructions

Cut the lumber into 1- foot lengths. Glue and screw nine

pieces together to form one 12” x 13.5” x 9-1/4” block.

Make two for use as pulling blocks, used to develop and

strengthen the second pull in the Olympic lifts.

Lincoln Brigham is owner of CrossFit Sedona .

He is a USA Weightlifting Club Coach,

CrossFit level II trainer, and CSCS (Certified

Strength & Conditioning Specialist) with the

NSCA (National Strength and Conditioning

Association). In addition to medaling at the 2002,

2003, and 2004 National Masters Weightlifting

Championships, he is a dance instructor and

dance competitor and medalist at the 2004 and

2005 United Country Western Dance Council

World Championships. He and his girlfriend

Adrienne Harris (whom he coached to a gold

medal and nine national masters records

at the 2003 National Masters Weightlifting

Championships) are probably the only people in

the country who have competed in and taught

both dance and Olympic weightlifting.

This would be a cool bumper sticker.

4 of 4

® CrossFit is a registered trademark of CrossFit , Inc.

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