Square tubing connectors needed for robot frame.

MarkS

I like the design of the robot prototype in the modular wheel thread. However, I was not too pleased with the bracket screwed on the outside of the tube. I understand its a prototype, but I want something a little bit nicer, and preferably in the tube.

I came up with these, but I am not able to machine them:









These could easily be done with 1" PVC plate. The only hard one would be the 90° tee (last pic), but it could be made out of two separate pieces and glued together. The connectors would need to take into account the wall thickness of the tubing, and this would force the use of one wall thickness. I don't see this being an issue though. The 3D models shown above assume a .188" wall tube.

Would this be within the capabilities of anyone here with a CNC router/mill? Would Parallax be interested in this for a robot frame system to go along with their motors?

Phil Pilgrim (PhiPi)

There are many companies that make "industrial erector sets", including fittings similar to what you describe. Here's an example:

www.brunnerent.com

But do a Google search on aluminum framing-systems, and you'll find a ton of 'em. The extruded T-slot systems are the most adaptible, since they allow you to position parts and cross members anywhere along their length, without having to cut the extrusion to make a joint. Some of them produce quite nice-looking structures.

-Phil

MarkS

The biggest issue for me is that I need a 45° connector and have not been able to find any. I spent about 2 hours on Google without any luck before posting this thread. The problems with the connectors you posted is that they are made for .065" wall tubing, which has little strength, and they have a lot of bulk material taken out to save weight, which compromises the strength of the connector. I've used these before and both the tubing and connectors are very fragile. I cannot find them for thicker wall tubing and I would need them to be solid. I'd really rather have them made.

Thanks for the help though.

Steve Joblin

Would either of these work?
http://gatorjaw.com/
http://www.8020.net/ (check out the Quickframe)

MarkS

No, I really didn't want to use t squares. I'm thinking that my best be would be to have someone weld the frame together.

LoopyByteloose

Cheaper and better to weld the square tubing. Welding will add a lot of strength to the frame.

If welding gets too expensive, round tubing that is bent into U shapes will reduce the welded joints.
I like square tubing better, but economics is always the trade off in design.

And aluminum is 50% of the weight of steel.

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