# Point Me To Some Simplish Steel Design Info



## AGCB97 (Sep 4, 2016)

I love to build things (3 airplanes, side by side ATV, Thousands of small things). The current project is a quad track vehicle center articulated, sort of a high mobility 2 seat ATV w/ a 4 cylinder 4 speed 4WD car engine and rear drive.

What I'm looking for is a little info on how to size square or rectangular steel tubing so it is strong enough to avoid twisting (within reason) and yet not so heavy as to be over kill. this will be for the frame.
I've googled some but not come across anything good so far. I do not want to become an engineer overnight but looking for some rules of thumb or personal guidance.

The side by side I built was made mostly of 2x2 1/8" tube completely fabricated from scratch by me.

Thanks for looking and in advance for your thoughts.
Aaron


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## jpfabricator (Sep 4, 2016)

If built in a cube or a triangle configuration like the sideXside, the 2"x2"x1/8" should be overkill.
Can you show us a rough mock up, or sketch of what you had in mind? That will help narrow down your choices.

Sent from somwhere in east Texas by Jake!


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## AGCB97 (Sep 4, 2016)

Jake

The main section (front) carrying the engine and on which the cab will sit will be a rectangle shape (about 36" wide by 60" long) made of 1/8" 2x2 or 3x2 with the 3" dimension vertical. It will be mitered, welded corners. On the back tube of this frame will be the pivot point for articulation, I'm thinking 10 or 12" between the upper and lower joints but that may also be over kill. Attached to this at the pivot points will be a similar size frame to carry the rear drive and a platform or box. This section will also need to twist with regard to the front to keep all tracks down on uneven ground. There will be no suspension. I guess the point of greatest stress will be the tube where the pivot point is, both front and rear. I thought of making this a higher aspect tube, say 6x2 with gussets to the side tubes.

I assume that 3x2 is much less apt to twist ( I guess I mean rack) than 2x2.

These tubes are also available in 14 GA .083 as opposed to the 11 GA .120

I may be over kill but that is what I want advice on.

Aaron


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## AGCB97 (Sep 4, 2016)

The side by side empty weight is 1540 lbs with a 1.3 liter Lecar engine. The track will use a 1.8 liter engine from a 80s Subaru. Quite a bit heavier. I also want to mount a 4' snow blower on the track and be able to do some light skidding.


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## jpfabricator (Sep 6, 2016)

I personally don't think you would have any problems with the 2"xs2"x1/8" tubing. Reproduction Cobras with 400+ horsepower are on 2"x4"x1/8" frames.
When you layout your frame, think triangles, and trapazoides. 
There's a popular Youtuber that says "Nothing too strong ever broke".



Sent from somwhere in east Texas by Jake!


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