"Swingman" wrote

I would also consider insetting/gluing the top "platform" in a dado, which
would increase the strength a bit more as well and/or, if weight is not an
issue, insetting a bottom, just like the top.

and a center for extra strength.


I have seen these plyometric boxes made of doubled 3/4" plyood. Esentially
an inch and a half plywood boards. That was strong and heavy.


Due to the taper, and the force from jumping, you might want to consider
interior cross bracing, to tie the tapered sides together, as well.

I have seen the wood boxes made with internal braces of steel. They were
attached with carriage bolts. This made for a smooth appearance and no
jagged edges on the outside of the boxes.

... I have a severe tendency to overbuild/engineer, so you might want to
take that into consideration as well.


Nothing wrong with that. Particularly if human flesh and bone hangs in the
balance. I have built a lot of gym equipment over the years and my stuff is
strong enough to support elephants.

True story; I was on a fitness newsgroup when somebody asked me to help him
with "step racks". This is just a simple plywood and 2 X 4 rack to protect
you if you fail at the bench press or squat movements. I made a crude
drawing in Corel Draw, and gave him some feedback to insure he built it
strong enough. He was intimidated by the project and had a carpenter friend
build it for him.

He became emboldened with his new safety devices and pushed himself beyond
his abilities to recover safely while doing the bench press. He lost the
lift and the weight crashed into the step racks. He ended up with a minor
bruise on his chest. He had a good scare and learned much from the
experience. Nothing hurt but his pride though.

He had his carpenter friend check out the rack after the big crash. It got a
clean bill of health and comment on he could now see why I emphasized all
the extra bracing and adhesive. I built a lot of these step racks over the
years and it felt good that I was able to prevent an injury in this case.
Sooooo....., there ain't no such thing as overbuilding when it comes to
flesh and bone.

Lee Michaels