frame tube size?

[SEVEN]

What should be the best size of the tube used to construct the frame? Do you think large OD with small wall thickness tube is efficient?

[SEVEN]

What should be the best size of the tube used to construct the frame? Do you think large OD with small wall thickness tube is efficient?

[Denny Trimble]

Large OD with thin wall is more structurally efficient if there is any bending, which there usually is in our spaceframes.

However, the rules require a major portion of the tubes of the car have a minimum wall thickness which negates the benefits of large diameter thin-wall tubing.

Also, packaging constraints make 1" and smaller tubing a little easier to work with.

Nobody's stopping you from going thin-wall large diameter, but it hasn't been very popular.

[SEVEN]

so which is more suitable for the frame: 1''OD with 0.095'' wall thickness or 1''OD with 0.12'' w/t ?

[jack]

thinner walls are more difficult to well too.

you think packaging bigger steal tube is a pain? try a 6" tube! http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Agent4573]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by jack:
thinner walls are more difficult to well too.

you think packaging bigger steal tube is a pain? try a 6" tube! http://fsae.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

They're only a pain if your trying to weld a very thin walled section to a much thicker walled section. If you doing two peices of .015 they're easy to weld, its just when you have to weld .035 to 1/8inch that the shit gets difficult.

[Storbeck]

Just throwing this out there, but I'd say it's more like the thinner the tube the better it has to fit together. It's easy to wild .015 if there is NO gap at all, but it's easier to weld .095 if there is say a .010 gap.

.028 to .095 isn't all that hard if it fits well.

My $.02

I agree with Denny, thin wall larger diameter is structurally more eficient for bending and buckling, which are probably the two failure modes to be concerned with, but with the minimum wall thickness it doesn't really pay to go bigger than 1"od.

[Frank]

.028 can be challenging for even an experienced technician

.035 is usually easy if the prep (fits) is good