2008-12-10t22:20:45 Z | TAGS:
Conditioning, CrossFit, Gadget, Health, How To, My Stuff How To: Make Stacking Plyometric Boxes
TEXT: How To: Make Stacking Plyometric Boxes
I got into crossfit.com just last month and it's fabulous. I've been doing their Workouts of the Day (WOD) daily for a few weeks now. I've been gradually accumulating the gear needed for CrossFit. I've bought a pair of Olympic barbell bars, some smaller plates, a kettle bell, and bumper plates will arrive soon. I already had a pull up bar but I'll probably upgrade soon. There are, of course, more things I want to get, but I think it's cool (and cost effective) when you can build your own (BYO) or do it yourself (DIY). I've already made the parallettes as per http://www.drillsandskills.com/skills/cond. One CrossFit fellow, Lincoln Brigham, already designed a BYO/DIY polymetric box for box jumping (http://board.crossfit.com/showthread.php?t=12749&page=1. The thing is I have kids and I need boxes of different heights. Separate boxes would just take up too much room.
Thus I designed these: Stacking Plyometric Boxes.
The cost for parts is under $30! Commercial ones costs hundreds plus shipping. (BTW: American measurements follow. My apologies to my fellow fans of the metric system.)
4" x 6" x 24' lumber. Cut into 12 pieces at 16" and 4 pieces at 19". (FYI: 4x6s are actually 3.5" x 5.5") I bought cheap construction grade wood at $3 per 6'.
0.75" x 2' x 2' plywood. Cut into a 17.5" x 17.5" piece. Thicker is better, but 0.75" was the thickest available when I shopped.
1.25" x 4' dowel. Cut into 8 pieces at 4". Sand half of each piece by around 1/8". Pre-drill a hole for a screw around 1" from the other end.
16 oz wood glue. More than enough.
1 pound of 3" wood screws. The next size down would have worked too. Try to counter sink these a bit.
The tools needed are minimal!
Power drill. With drill bit for pre-drilling dowel, Phillips screw bits, screw guide, and 1" hole cutter.
Rotary tool or similar device for sanding.
Small hand saw.
Two 2' wood clamps.
Corner wood clamp.
The design and construction is quite simple!
So simple that except for a few minor details, this picture should say it all:
The basic piece consists of joining 4 of the 16" pieces into a square.
Since I used pine, a fairly soft wood, no pre-drilling was necessary. I used glue and 2 screws at each joint: Bottom and middle, but not the top so you won't clash with the dowels.
Put handle slots on the basic piece by first drilling 1" holes around 6" apart. Make sure that the top of the hole is a little more than 1" from the bottom of the piece or else the edge will splinter. Then cut to join the 2 holes. Then sand down. I only put 2 handles per piece.
The top piece (at the right of the picture) is made by taking a basic piece and gluing and screwing in the plywood. Sand down the corners. The top piece with the plywood is 6.25" tall.
A middle piece (at the left of the picture) is made by taking a basic piece and gluing and scrwing in the dowel pieces into the corners. The sanded half stick out of the basic piece. Pre-drilling the dowels is important or else they will crack. You can make as many middle pieces as you like, but I have yet to find out what the maximum safe height is!
The bottom piece (at the top of the picture) is made by first making the handles on the 19" pieces, then gluing and screwing them so they surround a middle piece. I did not bother to screw at the corners, just at the sides. Alternatively, you could try using a middle piece in lieu of a bottom piece but I like the wider bottom piece to avoid tipping over.
Sand liberally for safety. Apply rubber matting to the top piece if you want. Paint if you want. Please note that these pictures used a base length of 18" instead of 16", but I'm posting 16" measurements because I think the smaller top would have less flex.
While my plyo boxes are heavier than the typical set, they are adjustable. My younger kids might use just the top piece, or the top and bottom pieces. I'll probably use all three pieces or throw in more middle pieces for more height.