Seamless lugs
 

Has any builder made a frame with lugs so long and thin that they became seamless once brazed?

I don't know of any modern lugged frames like that, but this 1940's Daudon has some lugs filed such that they blend into the tubing:

http://farm9.staticflickr.com/8465/8...cf15da2f_h.jpg

http://farm9.staticflickr.com/8330/8...7b7da5fd_h.jpg

Complete bike, seen at French Fender Day at Peter Weigle's shop (not my photo):

http://farm9.staticflickr.com/8473/8...4651004b_h.jpg

Sounds like an electroforged Schwinn although they are technically welded and ground flush not brazed. There were millions of them made. Sheldon has a good article on Electroforging. Roger

Older Ritchey bikes are kinda like that.

The Ritchey bikes aren't actually lugs though, they're fillet brazing shaped to look like lugs. "Faux lugs"

Edit, because this thread can use some more pictures:

http://velocult.com/wp-content/uploa...TB-Bike-14.jpg

This thread is cool, already.

I don't believe that's correct. They may not be full lugs, buy I don't believe they're "built up" brazing material. Rather they are partial lugs or sleeves.

Edit: Yes, bilaminate was the term I was looking for.

The Ritchey looks like bilam construction...

http://galluscycles.files.wordpress....g?w=768&h=1024

EDIT: Beat to it. Disregard.

Long and thin, no. Filleted into the frame, yes - on Alex Singers:

http://0.static.wix.com/media/1bc40e...fa.wix_mp_1024
http://www.thevintagebikelife.com/?_...72-alex-singer

-Kurt

I talking so thin that once brazed and finished one couldnt tell there was lug. Anyone can fillet a lug to make to make it disappear.

Why would anyone do this? This is a serious question.

Chris Kvale and Chris Bishop have serious filing/finishing skills.

They come as close as anyone.

http://farm9.staticflickr.com/8163/7...b86ef177_b.jpg

http://farm9.staticflickr.com/8483/8...d24b5644_b.jpg

http://farm9.staticflickr.com/8338/8...e1876f08_b.jpg

http://farm8.staticflickr.com/7057/6...519f3473_b.jpg

Wow my job is easy.

Yes indeed, this is "bi-lam". There's no advantage to it over lugs or fillet brazing, but it's worth style points in my book.

Weigle made som bi-lam bikes:

http://farm3.staticflickr.com/2528/3...778_z.jpg?zz=1

Mother effer, that's some pretty stuff.

My, My My....you're making me want to NOT look at my bikes....makes mine look like they were assembled by Gorillas with large stone mallets! Those are just SOOOOOO pretty!

To make a frame look seamless like modern carbon frames. Back in the day some of the Miyatas had a one piece head tube lug combo.

Those are stylish, if I was the client though, I would ask that the seat lug not be finished off that way for the seat post. Just my practical side.

I think the closest bike to what the original poster is asking would be in my mind although I cannot locate the image is the prototype 3V where the "rings" at the end of the tubes did not show, in that case the lugs were internal save for the head tube. Albert Eisentraut also filed lugs to kleenex thickness, but everyone I have seen who did lugs back then left the witness of a lug edge.

Why doesn't fillet brazing qualify if it's just for aesthetics?

This is Dave Kirk's work.

http://i32.photobucket.com/albums/d7...edHeadTube.jpg

I believe Jim is working his way to a theory about lugged frames as a strength consideration.

-Kurt

ANYTHING is better than UGLY, Sloppy, TIG Welding? The old Schwinns were well done for what they were...strong and heavy.

Sure does in my world.

As nice as his work looks, it rides even better.

Rode a Terraplane this past summer and that memory has not left me.

Interesting! I learn something new every day.

Someone on these forums has a Ritchey touring frame that they had posted a thread about, that was the first I had heard of this style. I didn't know it was separate fillet brazed lug sleeves but that makes sense since the logistics of shaping the fillet brazing to look like that blew my mind. The picture brockd15 posted helps clear it up.

However these are made, they are absurdly beautiful. So many nice frame pictures in this thread already, I really love that Singer. I see a lot of really beautifully built frames using traditional, but nicely-filed lugged construction, but this style of craftsmanship makes these frames stand out for me.

Chris Bishop has a quite "praktisch" side as well.

A share of his work has an earthy, street smart sensibility.

Single speeds, fixies, track bikes etc.

On the other hand, when he shows his considerable skills, they burn a memorable picture for me.

When frames fail, for whatever reason, they tend to fail either at, or very near to, the points where the tubes are joined together. To overcome this tendency, builders make the joints stronger, and the ends of the tubing stronger, so they don't fail. If the builder reinforces part of a tube, there will be a point of transition from the stronger part to the weaker part; that point of transition then becomes the weak point, and therefore the point at which the tube is most likely to bend. Thinned lugs and lugs with long points, whether singly or in combination, are ways the builder attempts to make the transition as smooth as possible so that the force is never concentrated at one point. If the bending force is concentrated at any one point, the tube will deflect there; if the force can be evenly distributed, the whole tube can flex while under stress, but spring back as soon as the bending force relaxes.

When a bike is crashed, head-on, with enough force to bend the frame, the bend(s) typically occur on the top tube and the down tube just after the head lugs. I have seen such bends on a butted frame, where the bend is on the butt itself; that is, on the part of the tube that has thick walls. I don't think I have seen a frame that had actually bent on the lug, or even on a long pointed extension of a lug.

The gorgeous Chris Kvale and Chris Bishop seat clusters shown on the last page make no sense to me. This is not where frames bend.