The problem with looking to the internet for frame tables is everyone has different purposes for their tables. If you are building top fuel or nascar chassis you need a surface _plate_ to work off of. This is different than what we need. A fixture table or surface plate needs a level surface, machinists level, and several holes to bolt different tooling to. We are not building space shuttles, we are building prototypes out of cars that usually had a tolerance of plus or minus an 1/8". We need a platform that gives us a solid foundation to measure and build off of, we need access to all sides of the car, we need to be able to adapt, on the fly quickly and easily. If I am building fixtures and tooling, I am not making progress on the car.
The table I pictured is nearly a direct copy of the table that RadRides uses. The first table I had, had a ladder structure on the top made of 2X2 on 2" centers, big gussets at all the legs, crossmembers on the bottom tying the legs together and all of that stuff was just in the way. After using the second table, I realize that you just don't need all the structure.
If you weld your frame to the table, you just increased the strength of both pieces....even if it is just temporarily.
I'll answer the welding question here. The legs are welded on with two welds side to side and the crossmembers are welded with two welds vertically. You want to avoid welding on the corners of the main rails, that is where most warpage will come from. As I stated in an earlier post, I built the second one on the first one. If the center ends up low, that's okay, with adjusters at 6 points, you can jack up the middle and the weight will settle the ends in and you will be level. Less than an 1/8" of pre bow is all it takes.
The less you can weld to the top section or rails, the flatter the top surface will stay. The thicker the material the more you can weld to the actual structure without it pulling or moving.
You will never have 4000 lbs on your chassis table unless you add everything to the chassis table for mock up. Dynamat, glass, and interior parts. The chassis table is just used to get the parts to a roller in the fab process typically.
I'm glad it's helping others! Some of the threads on frame tables tend to stop without any finality... if that makes any sense. I'll probably do another design in Sketchup, but that's more for the practice than anything.
You will never have 4000 lbs on your chassis table unless you add everything to the chassis table for mock up. Dynamat, glass, and interior parts. The chassis table is just used to get the parts to a roller in the fab process typically.
This is one of those duh moments. I do plan on assembling the drivetrain, frame, suspension, and body on the table. However, many of the little things that add up weight won't be added until it's back down.
Brian Hobaugh SCCA National Tour June 2014
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