One friend that says c-clamps are the same thing. Another friend thinks I should drill holes for bolts (where I'd fasten them with wing nuts).
Are c-clamps good enough to secure a small truck's cap/topper?
Use C-clamps in place of mounting clamps for truck cap/topper
fastening
Related Solutions
It’s based on the 1) angle of repose, and 2) weight of soil, and 3) length of deadman.
7-8kn equals about 1500 - 1,800 lbs.
If the angle of repose is about 45 degrees and your soil weighs about 80 lbs. per cubic foot, then you’ll need about 2,000 lbs. (safety factor) resisting.
Therefore, you need to bury your deadman about 3’ deep if the deadman is 3’ long. (I’d compact all material in the ground.)
I’d worry about a 2” diameter deadman getting pulled through the soil and compacting the soil immediately adjacent to the deadman. You’ll need a wider diameter deadman, such as a 12” wide x 3’ long steel plate welded onto your 2” pipe.
Adjust accordingly for your 15-17kn.
Have a bonfire and go buy some straight 2x4's (those certainly appear to be 2x4's)
Or possibly some nicer wood, depending what you intend for this table. My eyeball assessment is that this is ordinary framing lumber ("studs") which is commonly "spruce, pine or fir" and nothing special to look at.
Salvaging what you have will be tedious frustrating and largely pointless, IMHO unless this particular collection of wood has huge sentimental value.
The only "get rid of the twist" method I can recommend is to remove wood until the boards are thinner, but flat. That is a somewhat challenging prospect if you have limited experience with woodworking. Wetting generally only makes a difference while it's wet, and when it dries out it goes right back where it was. Steaming is a huge operation, then you need to move the wood somewhat beyond where you need it to end up, as it "springs back," and clamp it there until it cools and dries. If you have correctly guessed the amount to overcompensate for the current twist and bow you might end up close to straight.
Meanwhile, you could have had that bonfire and gotten some straight dry wood...
Best Answer
A large C-clamp is probably strong enough, but it is more likely to slip off. I would not use this method. You don't want to have to explain to an insurance company why your method failed and severely damaged several cars, or worse. Use the topper manufactures recommended method (probably bolts and some type of locking nut, not a wingnut).