Doubled 2x4's bolted and glued, not screwed together, with cross supports should be fine. Like this but the supports that tie the main supports together look like they're screwed in. I wouldn't trust any significant weight with wood screws.
i didnt build one out of wood but i did buy a Cybex rack that was missing parts and reconstructed it with wood. Doesnt look bad and works. Only advise i have is over engineer the crap out of it for your own safety
Thanks for the link. I may think about this someday. I do some woodworking and have an olympic barbell set. I built a weight tree for it out of 2x4s and pipe nipples that works pretty good.
I'm not sure I understand your question though. If you you're questioning if you can build it, maybe it's not the project for you. You'll need a drill, appropriate size bits, circular saw, screw driver (or bit for the drill). Having a table saw or mitre saw would help in cutting the angle for the braces.
As for cost of materials, geez, the site gives you free plans with a BOM (bill of materials). Go to your local home depot / hardware store and price them out. They claim < $150.
I know for sure I could build this. With out a doubt. I am just wondering when I put some heavy ass weight on it if it will hold. Second how much the wood is. Its not like I buy wood all the time.
What about using thicker support posts. Then you would not have to glue and bolt together 2x6's. The only thing I can think that might happen is the post might crack if you dropped the weight at 500+ lbs
There shouldn't really be much force on the screws pulling the beams apart. I've jacked my porch roof up using just 2x4s to replace the main columns this summer. I also supported the garage in my last house with 2x4s screwed together when my brother and I replace the main header beam that ran accross the top of the two car garage door entrance.
In my opinion, the screws are fine.
If you're really worried though, you can get a good wood glue that bonds stronger than the wood itself. The design calls for the vertical posts to be made of two 2x6's. In that case, the main role of the wood screws would be to clamp the beams together till the glue sets.
The problem with these types of racks isn't the lumber itself. I built a dip stand out of lumber and it is plenty strong. Doubled 2x6 uprights are plenty strong to support the weight 99.99% of people will be using (although he would've been better off with 4x6's). The problem is in the joints and the fasteners. This guy has his attached to his floor joists with a 2x2 and some L-brackets, but in order to keep the front bottom from spreading, the bottom 2x6's should be attached to the floor with concrete anchors. The 2x6's along the top should also go all the way around to prevent the upright pieces from bouncing.
He is also misusing wood screws. First of all, I notice that he has pressure treated wood, so every fastener on the thing should be stainless steel, ceramic coated, or hot dipped galvanized. A regular wood screw is not very strong at all, and the copper in the treated wood will cause them to corrode. Many of those joints should have 3/8"-1/2" hex bolts or carriage bolts (all hdg), and most of the other fasteners should probably be 10d-16d nails.
I could go on and nitpick some more, but the bottom line is that I bet this guy still spent close to $150 on this thing. You can find a decent used (steel) rack on craigslist for a similar price.
Well lets say you have 495 on the bar and your doing rack pulls. Its about a 12" lift. But you never control descend the weight. I normally let it clang on the bar and lift back up. Point is would the holes for the support bars handle it or would the wood split. Thats what I would be concerned about. It might not happen right away but over time it might. That is my only concern.
Go to lowes or homedepo and talk to a semi knowledgeable guy..use a good hardwood with the right heavy duty bolts etc. dont be to reckless with the weight though..dumping the weight might not end well. Personally I would do it though.