pic: Pyramid Problems
 

Re: pic: Pyramid Problems
 

Had a little bit of that. Not nearly as drastic. We used some pipe clamps under the rung to hold it level, then started tacking things in place. You need to get someone (or multiple people) to hold the twist out of it while it's being tack welded. We worked from he bottom up. I wouldn't try to do the whole thing at once.

Re: pic: Pyramid Problems
 

We use 8 packing straps attached to the top corners and adjacent lower corners and the tighten them up carefully with the ratchets. It makes the tower pretty firm.

Re: pic: Pyramid Problems
 

Remove the chairs and step to the right. That will fix your problem.

Re: pic: Pyramid Problems
 

Bolt the top joints together. That should fix your issue somewhat.

Re: pic: Pyramid Problems
 

There is nothing wrong with there joints. All you need to do is step right one step and remove the chairs

Re: pic: Pyramid Problems
 

I see it corectly, we built it similar to theirs. We had the same issue. Put some bolts through the top inserts and that fixed it.

Re: pic: Pyramid Problems
 

Cut the corners at 45 degrees instead of butting them up against each other

Re: pic: Pyramid Problems
 

What bolts?

Re: pic: Pyramid Problems
 

The bolts are mounted on the gusset plates, and basically what we do is drill a hole in the leg, and put a bolt through it and there is a nut welded to the gusset that holds it there, and it keeps the levels of the rungs consistant.

Re: pic: Pyramid Problems
 

Check out this other thread for internally bolting your pyramid with mostly off-the-shelf H/W and one custom part => threaded internal sliding donut

http://www.chiefdelphi.com/forums/sh...43#post1213343

The holes in the threaded aluminum donut plug inside the rung pipe were mistakenly drilled at the 98 degree dihedral angle, instead of the correct 90 degrees, which accounts for the miter gap and the spacer stack skewing over in this initial test assembly. The nylon "curved end tube spacers" are the key to the whole concept working. We may need to glue their flat ends together with the curves rotated to the proper tube angle offset to each other to further improve joint stiffness



-Dick Ledford

Re: pic: Pyramid Problems
 

We also had some twisty-turny stuff.

We made plywood gussets for the corners, serving the same function as the nylon spacers shown above, and that tamed the pyramid.

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We used Lots of different sized Jigs to hold things in place. also, as mentioned above, clamping under where the squares rest (to hold them up) and then measuring, tacking, measuring, cussing, cutting, and welding it up. ours turned out fine though. One thing that helped was putting a small but tall welding table in the middle and welding up things (and holding the top box up and twisting it.)

Re: pic: Pyramid Problems
 

If you make a big X out of the metal pipes (not in the original design), and weld the legs diagonally to it, it shouldn't twist as much, but there may be problems with your robot driving over it, since it'd be flat on the ground...

Re: pic: Pyramid Problems
 

We made a full welded pyramid and had the same problems. After a lot of struggle some local welders helped us out for free. Thanks welders!