9 Dec 2008

The tubing is here, bent tubes, too! A big thanks goes out to Phil Burke and everyone at BurkeBuilt Fabricators for helping me get the tubes bent. Lots of places can bend 0.125″ wall tubing but not many can do 1.5″ x 0.095″ wall. Unfortunately I had the wrong bend radius on my drawing but they fixed it, which means some tube drawings have to change… which is another reason the tubing drawing issue bugs me. Anyhow, different businesses use different bend radii in their benders, making the main hoop and windscreen slightly different shapes and affecting tubes mating to them.

Received some good comments on what information to provide for tube fabrication. Of course the suggestions range from, “they don’t need anything”, to, “give them everything and let them pick what they need.” The answer’s somewhere in the middle; the trick being to not spend a lot of time providing info builders don’t need or can’t use.

Since Burke deals with this stuff all the time I asked his opinion on how much information to include, noting that a builder is typically one guy in a garage using a grinder or tubing notcher to do the ends. He had a good example: a simple angle cut on the end of a round tube. At shallow angles, the tip of the tube on the drawing will be quite long and sharp. However, in the real world it won’t be nearly that long because it’s not possible to weld such thin metal; it’ll either melt back or get ground off during deburring. His point is that measuring to the tip is only useful as a guide of how long to cut the tube before notching it. Another example for this same tube: the open end of the tube is an ellipse, so the centerline length of the tube is measured to the center of the ellipse. But how is a builder going to do that? It’s very difficult if not impossible before it’s cut and dang hard to do even after.

I know I keep beating this topic to death but when people who know this stuff say don’t bother with detailed drawings it makes an impression. Maybe it’s my excuse why tubing detail will be minimal on unimportant diagonal tubes but more detailed on important corner tubes. As was pointed out, probably the most important drawing is the one showing where the suspension pickup points go; everything else is just a big bracket to keep them in place.

A shelf will be added under the build table to store the tubing up off the floor. Learned that lesson the hard way last time; the tubing rusted quickly from the moisture coming up through the concrete.