mikeread

I am toying with the design of a bilaminate frame and am trying to get my head around what I can and cannot do with regard to the shape and size of the lugs/laminate/sleeves.

Looking at the lugs you can buy, they are all of very similar design and this must be for a reason. If I am going to make my own, I don't want to just copy what has gone before, but neither do I want to repeat mistakes of the past.

So anyone with a view on these things, I would be pleased to hear your opinions.

Things I am thinking about are:

The points of a lug are always on the top or underside of the tube, why is this? I assume this is the plane of maximum stress?

Why do the lugs have points at all? I assume it is to prevent a sudden change in cross section and distribute the stress, but if this is the case, why is the underside of the lug sometimes rounded?

A tig welded frame has nothing to distribute the stress so why does a lug need it? could a lug just be a short round collar - like a big tig weld?

If the points are for looks only, why is there not more variation? I accept there are plenty of variations of ornate lugs but the basic shape is very similar on most I have seen.

Thanks

Mike