bilaminate lugs of sorts

[Tom Kellogg]

Now for our .02. We've had a progression over the years from close to 100% forged or cast lug construction to making 100% of our lugs. During our first few years, we only used Prugnat bulge forged lugs since that was pretty much all there was for us to use.

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We even used them in our tandems, cutting them apart and piecing them together where necessary. By the late '70s, we had migrated to cast lugs once Hank started producing them. His early stuff was hard to work with ... super hard condition, but still better than the forged lugs. At this time, the only non-lugged construction we were doing was fillet work on tandem BBs and the like. We did not have a source for lugged tandem shells in any case.

Right around the turn of the millennium, we needed to make a number of frames which no one made lugs for. The angles were too unusual to adjust lugs for or the tube diameters did not permit lug usage. Our solution at the time was to build true bilaminate frames. The track frame that Sarah Uhl rode to the world championship was one of these, built in late 2000. For her frame, we started with Hanks lugs and simply removed the top tube and down tube portions and brazed up the frame with fillet work where there was no longer a lug to support the tube.

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After dicking around with this style for a couple of years, and finding that we were using it more and more with the advent of compact frames, we finally just gave in and began making our own lugs for all of our frames. We'd gotten pretty good at it by that point since we had been making all of our tandem lugs since about '85, including our bottom brackets.

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So are our frames built with our custom made lugs bilaminate construction? Not from our point of view. They are simply lugs from a different source than they would be if we bought them from Hank, Ritchie, Llywellyn, etc. We continue to make them because it allows me free range when designing a frame. Any top tube slope, any angles, any diameters, etc. Once we begin jigging up the frame, Jeff can then alter the lug shorelines to suit the angles. And he does. Each lug has subtly different shorelines depending on tube diameters and angles. Is it worth the extra time? The answer is not simple. Are the small design changes I make because I can, worth the effort? In some cases, yes. There are times when I can make a better frame for a client because we make the lugs. In other cases, the difference is subtle at best. We stick with it simply because we never need to consider lug availability when designing a frame. Design first, then build the lugs.

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[Curt Goodrich]

I generally define bi-laminate as a sleeve on one side of the joint and no sleeve on the other side of the joint. A lug is a sleeve that holds all the tubes of the joint. Since there aren't any new ways of sticking tubes together I don't have any concern why someone chooses one technique over the other. In other words, it's all been done before so I don't see a technique as old or a reenactment while others are modern or more relevant.

[Too Tall]

I generally define bi-laminate as a sleeve on one side of the joint and no sleeve on the other side of the joint. A lug is a sleeve that holds all the tubes of the joint. Since there aren't any new ways of sticking tubes together I don't have any concern why someone chooses one technique over the other. In other words, it's all been done before so I don't see a technique as old or a reenactment while others are modern or more relevant.

Sooooooooooooooooooo, I'd love to hear what the OP has in mind. tap tap tap tap Drop a dime will yah?

[Mike Mcdermid]

Gentlemen

Thanks for the time you have put into this this thread ,great insight into the history from the people who can put the knowledge into words and the closeup photos and information supplied by Mr kelogg it confirmed a few of the things I was thinking/having issues with.

TooTall I was enquiring to the technique purely as I wanted to follow a path which is more classic ,irksome problem is lugs for tubes I have etc want to use etc . It certainly shows the level of quality you have to achieve to work at however to produce top end frames.

[Chik]

When these chats come up (and I realize I am encouraging the discussion) I often think of the transmission/tradition text that lives here.

Apologies for the dredge, and I have nothing to contribute to this thread; I just came upon this thread wanting to understand what a bi-lam actually is. However, I found the linked text very interesting. I frequently talk about the distinction but in a different way. The text is probably more concise and to the point. Anyway, thanks, Richard.