Quote:
Originally Posted by Joseph Smith
I've been investigating some new design and construction methods that my team hasn't explored in the past, and I really want to try assembling the frame and important structures with machined gussets and bolts. I have a few questions for teams who have used this construction method. In this scenario, I'd be using two gussets, top and bottom, to create a 90 degree joint between two lengths of rectangular aluminum tubing, all 1/8" wall thickness.
1. Is it better to put a long bolt all the way through and use a nut on the other side, or to tap the gusset and tubing and use shorter bolts?
2. If a bolt all the way through is used, are large washers needed to spread the load to prevent the tube from being crushed?
3. If the parts are tapped and a short bolt is used, would it be preferable to tap both the gusset and the tubing or to drill clearance on the gusset and only tap the tubing?
4. Is locktite a necessity with the tapping method?
5. What has been your overall experience with this method of construction? Pros/Cons?
Thanks!
I should clarify, with the pretapped method, we would be using machine screws or something of the sort.
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Rivets are the way to go. There are different choices of rivets that will give you different strengths.
Bolts are heavy and time consuming to take out during quick repair in the pit. If it is a critical joint with a very high load, use bolts. I would get it all the way through and put a spacer in between if you have access. A washer will help reduce the chance of collapsing the section but if a student wants to use a drill to tighten a bolt and not paying attention, you can still collapse it. We always use lock nuts so no locktite is needed.
To save weight, I would use 1/16" high strength aluminum alloy for the two gussets.
We usually use rivets everywhere and more rivets in area with anticipated higher loads. If any rivets failed during matches, we just replace them. If it is in an area we do not want it to fail again, we would replace with bolt and nut. If you don't have access to use nut, then use self drilling screws for repair. They work really well.