Who or what company was the first to do a peirced seat tube and whats the advantage?

Hoo boy...This is a guess...JMC?

That old Gary Turner, that was pierced eh?

The joint is stronger than conventional.

Unless that's a trick question, like the TOP tube is actually pierced and the seat tube goes through it!

Ok, not a trick question, but yes, top tube is pierced buy seat tube?

JMC
GT
GJS Big tube
VDC

Any others?

BXC, Nat. Pro, Privateer, Nomura, Pro Dyne, Cal Cruiser.

Voris used em' alot on frames he built for other companies.

Why? Advantage over a tube ending at and welded to seat tube?

More metal around the joint.

If you bored a hole through just big enough for a friction fit, then slid the smaller dia. tube in, you've already got a union that can withstand a degree of stress against it. Then when you weld, you make it permanent. You've got not only the weld, but the bigger tube around it giving it strength.

So why did the others not do the same?

Probably cause they didn't want to look like they were copying GT! (the most well-known with that design)

Ohhhhhhhhhhhhhhhh how I would like to find a Privateer frame and fork!!!! Those things were awesome....

It's called mitering, and it was more expensive to do - that's why some manf. opted to not do it.

When you miter the seat tube it has to line up perfectly wit hthe miter you apply to the front of the top tube, and the radius of the head tube. Then the miter on the bottom of the seat tube has to line up perfectly with the radius of the bb shell.

This limits your adjustments in the jig, no fudge factor as everything must line up.

That's why JMC and GT were two of the best bikes BITD - the kind of attention it took to do a proper miter was something only the best could do.

Part of the reason anyway, imo.

Traker too.

Jim Melton told me a few years ago that GT pierced the TT w/ the ST before JMC.