Tube Versus Channel

[qzrrbz]

Originally Posted by Kevin Sevcik

(Last thread derailing, I swear)
Rivnuts are definitely cool and we've used them before. Did I mention we have gorillas on our team? Last year they cross threaded a bumper attachment screw in a rivnut, then spun the rivnut. We missed a match getting that bumper off and replacing that rivnut. So we're running reversible bumpers now and are a little more cautious of rivnuts.

Another semi-endorsement for rivnuts. They are really cool things, in theory. However, beware of using in 1/16th wall stock -- very easy to spin them, and then you have a mess. Installation is also an art! Too much force, thinking to make a better seat, tends to mess up the threads, especially in aforementioned 1/16th wall. Still, they're pretty neat and tidy when done well!

[Walter Deitzler]

1 question that I have that I have not seen mentioned is price. What is the cost of the tube versus the kit bot c-channel, which is included with the KOP. If it is expensive, I don't see much bonos to it over C-Channel, which works fine for most uses (at least for 3397). We used it on our chassis and tower and electronics mount. It is light and pretty durable. So, unless it has a VERY good benefit, I do not see the point of buying the tube.

[smclean1969]

If you have a local aluminum supplier, just tell them that you'd like to purchase any 1"x2"x1/8" or 1/16" wall aluminum that they have as scrap. You can cut your costs from about $3.25 per foot to $.40 per foot. Work it year round and you'll have plenty of material come build season.

[Hawiian Cadder]

We used 3*1.5 inch tubing with .125 thick walls and a special hole pattern cut into it this year. 3/16 rivets and grade A 10-32 Button-heads are our fasteners of choice. This year the drive frame weighed 10lbs, and the entire frame weighed less than 16lbs. If you have the machining resources to do it, I would look at perforated tubes as a construction method, I cannot think of a way to make a lighter frame. For some examples check out team 40 or 111's robot from 2011