CrossFit Discussion Board  

Go Back   CrossFit Discussion Board > CrossFit Forum > Equipment
CrossFit Home Forum Site Rules CrossFit FAQ Search Today's Posts Mark Forums Read

Equipment Outfitting a serious gym. Vendors & suppliers. Devices & equipment

Reply
 
Thread Tools
Old 06-14-2007, 02:24 PM   #1
James Falkner
Member James Falkner is offline
 
James Falkner's Avatar
 
Profile:
Join Date: Apr 2005
Location: Orlando  FL
Posts: 608
Is it worth it to build a 48" box to do box jumps? My max is currently around 43" but I am shooting for 48". I've been stacking bumpers on top of my 25" box so far, but wondering if its worth it to build a true angled plyo box. The base would have to be pretty huge to avoid being top-heavy, and I am worried the box would be too heavy to be practical. Thoughts? Should I just stick with the bumper stacking? I will have to combine bumpers with 45lb iron plates to get up to 48".
  Reply With Quote
Old 06-14-2007, 04:16 PM   #2
Patrick Donnelly
Banned Patrick Donnelly is offline
 
Profile:
Join Date: Apr 2007
Location: College Park  MD
Posts: 1,162
Wouldn't it be better to stack the bumpers UNDER the box? Putting them ontop seems pretty unsafe to me in the first place.

Solution for the top-heaviness:
- make the box nearly a rectangular prism with 3 out of 4 of the sides perpendicular to the ground
- make that 4th side slanted
- the both the top and bottom would be rectangles of the same width, though the bottom would be slightly more elongated
- place this box with a flat side against the wall, and the angled side facing out
- when you jump on it, it won't tip over because the wall is there to block it

(Message edited by whiteninja on June 14, 2007)
  Reply With Quote
Old 06-14-2007, 04:23 PM   #3
James Falkner
Member James Falkner is offline
 
James Falkner's Avatar
 
Profile:
Join Date: Apr 2005
Location: Orlando  FL
Posts: 608
Patrick,

Great idea for construction!

I can't stack bumpers under my current plyo box because the base is bigger than the bumpers. And stacking on top, they are pretty solid (approximately 200 lbs of hard rubber stacked on top of a large plywood box ain't goin nowhere). However, it may be a problem in that if I *barely* miss a jump, I could kick the top bumper off or kick it slightly out of place, and come down.

  Reply With Quote
Old 06-14-2007, 04:47 PM   #4
David Sailor
Member David Sailor is offline
 
David Sailor's Avatar
 
Profile:
Join Date: Feb 2006
Location: Londonderry  NH
Posts: 533
James,

Why not make a couple of risers to go under the boxes you currently have to increase the height? I made a 6" and 12" riser to go under and each are stackable together or separately. I can put them under either the 20" or 24" boxes I have which makes for quite a few variations in height. Mine are simple 2x material for the sides and plywood for the top. They are not elegant or pretty. They are heavy which bodes well for stability but not for portability. But they do work very well at what I wanted them for: a lot of differnt height options, ease of use and safety. I'm not toting these things around, they stay stacked under the boxes and I pull them out when needed. David
  Reply With Quote
Old 06-14-2007, 06:57 PM   #5
John Biddle
Member John Biddle is offline
 
Profile:
Join Date: Nov 2005
Location: Brisbane  QLD
Posts: 139
I was going to suggest making a second box, to fit on top of or under existing one. Make it the same width as the existing one, and secure it to the existing one with catches of some sort on the sides(maybe window catches for wooden windows?) A series of risers sounds simpler though (and more scalable). Maybe drill a couple of holes through them and put thick dowels through (eg old broom handles) to secure the risers. Put the box on top. Can't be hard to work out a system to secure the box to the top riser if you want to - maybe a couple of bolts out of the top of the riser through some metal or wood fixed to the bottom of the box, secured with wingnuts.
  Reply With Quote
Old 06-15-2007, 07:48 AM   #6
Paul Findley
Member Paul Findley is offline
 
Paul Findley's Avatar
 
Profile:
Join Date: Jan 2006
Location: Longmont  CO
Posts: 1,257
SAFE for even the most timid (work, family etc.):

http://www.crossfit.com/discus/messages/26/41132.html

I could have sworn I posted this yesterday...Here is a 36" box I made. You could make a similar 48" box that is stable and not too heavy. I don't think you want to launch that high on a stack of stuff.
  Reply With Quote
Old 06-15-2007, 08:57 AM   #7
Lincoln Brigham
Member Lincoln Brigham is offline
 
Lincoln Brigham's Avatar
 
Profile:
Join Date: May 2003
Location: Kirkland  WA
Posts: 3,987
The base does not have to be huge. As long as it is a few inches broader than the top it should be fine.
  Reply With Quote
Old 06-15-2007, 11:08 AM   #8
James Falkner
Member James Falkner is offline
 
James Falkner's Avatar
 
Profile:
Join Date: Apr 2005
Location: Orlando  FL
Posts: 608
Paul, is that 1/2" plywood? What kind of plywood? How much does that box weigh?

I had some scrap 3/4" that I used for my 25" box (it was the plywood I slept on as a kid :-) ). My box is pretty heavy (I'd guestimate maybe 30 lbs?). It's that super-thick "marine grade" plywood". (WFS link to wikipedia). I guess that's why its so heavy.

  Reply With Quote
Old 06-15-2007, 04:03 PM   #9
Paul Findley
Member Paul Findley is offline
 
Paul Findley's Avatar
 
Profile:
Join Date: Jan 2006
Location: Longmont  CO
Posts: 1,257
Its like 22/32...what used to be 3/4".

Its got some weight, but its not bad. Not in a place where I could guesstimate.
  Reply With Quote
Old 06-17-2007, 12:56 PM   #10
John Milgram
Member John Milgram is offline
 
Profile:
Join Date: Oct 2006
Location: Cleveland   Ohio
Posts: 84
Maybe you don't need to go to any construction trouble:

http://www.youtube.com/watch?v=USRhHy6Ixh4

(safe)
  Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Plyo Boxes Jay Soto Equipment 14 05-25-2007 11:40 AM
Boxes for box jumps Jonathan McMahan Equipment 0 07-03-2006 11:58 PM
BFS vs Power-Systems Plyo Boxes? Matthew Nielsen Equipment 13 04-05-2006 09:21 PM
Homemade Plyo Boxes Paul Findley Equipment 5 01-20-2006 08:46 PM
Building plyo boxes David Smit Equipment 1 07-30-2004 06:50 AM


All times are GMT -7. The time now is 12:57 PM.


CrossFit is a registered trademark of CrossFit Inc.