Filed lugs... anyone know stuff?

:)

i don't hate.

aww. Loathe then.

@skully - I think I understood what you were saying but this is definitely a case where a picture beats words all ends up.

yeah ive been thinking about doing this on a rank frame i have sitting around. i was going to file and then progressivly sand the edge of the lug.

i dont think this would damage the frame integrity.

i need to get a new set of files though as i only have butch ones for carpentry.

can you post some pictures of some good examples?

Mmmm Fillet.....

I think I know what Skully is on about. and if so this is one way which I have read about people doing something similar.

Lugs you buy from ceeway e.t.c are pressed or cast. You can however make your own, this may be because you want angles or sizes which are not avlible but want to have the aesthetics of a lugged frame.

Simply by tig welding two short tubes together with the required i.d then filling down the weld to a smooth finish. Prob by laying several fillets on top of one another so you have extra weld to file. The fixie inc frames have this filed tig weld look on them. You can then use this custom lug to braze your two tubes into.

If you wanted to create the effect of say the top tube and down tube going into lugs at the head tube but the head tube being fillet brazed into the down tube / head tube you could use a similar method. Weld two short tubes to you head tubes at the required angles. File / polish down the welds. Cut off the mini down / top tubes to lug length, cut any patterns you want into them then braze in your down tube / top tube.

ah Got it!
http://www.cygnus-x1.net/links/lcars/blueprints/excelsior-blueprints-sheet-2.jpg

Opposite way round to how I was talking about. This one is top into head tube looks like fillet brazed. Head tube looks like it's into a lug.

But by the look of this photo, nothing has been filed away after it has been brazed.

Wouldn't skully's idea just fade the lug into the tube, creating a smooth finish, but one which would be noticeable as there is a change of thickness of the tube where the lug is?

Yeah I think your right. But unless your building a frame from scratch and doing something similar to what I was talking about it will be difficult not to have the problem you talk about. It would still look good.

Thinking about my method you may also beable to fillet braze with brass where I said tig and silver braze the tubes into the lug tube type interface. The main advantage of this would be not needing a tig welder and it's easier to file / polish a brass join than a welded one smooth. I am not sure but I think there is a sufficient melting point temperature difference to allow this. I am no welder though so this is just some basic theory.

Like many things I am sure there are many different method with different pros / cons.

yes you can definatly still see where the lug would have been, due to more material there than the rest of the tube. but you dont really notice it and it just looks like its fused.

i haven't got a bloody clue what you are on about.

31, you posted a pic of this!

https://www.londonfgss.com/thread16386.html

I think it probably makes sense to reshape the lugs before brazing. The couple of examples above seem to have been done that way.

The opposite is done also, known as laminated lugs, basically wrapped on afterwards, e.g paris cycles. Are we meaning this or t'other way round as in Tommy's posting?

Or, leave it in the rain and let them corrode...

From https://www.londonfgss.com/thread29-216.html#post519314

@kowalski, i know i posted that pic, just couldn't (not wouldn't) understand/picture what the hell skully was blabbering on about :)
but once i saw the pic to describe it, i realised, hence the "ahhhhhhhh, i gotcha"
x

OK

I don't want to build a frame. I don't want to shape any lugs before brazing. I don't want to TIG weld anything thankingyou please. I already have a frame. Its nice, but its not going to win any beauty contests. I only want to alter some slightly fugly lugs around the front on the head tube, by filing them smooth into the profile/line of the head tube toward the front, but leave the lugs as was where they grip the TT and DT. So I would taper the filing toward the back, out to the original curve of the lug surface. The back bit of the lug isn't so chunky looking. I guess my worry is where/how much to remove and how to get a clean shape to it around the barrel of the head tube and near the head tube end faces. And I'm concerned about damaging the original tube underneath. I wonder whether or not the headtube would look weird if there were tapers near the top and round the back. Like dogs said, a steady hand.

I want to know if you are all saying 'no on no account try to file off the lug edges toward the line of the tube' or 'yeah give it a go'. I would like to try it and bloody hell I might just.

ah, right, remember that lugs have cut-outs to increase the brazing area size, it probably doesn't run too far under/between the two surfaces. so, filing down/smoothing the lugs into a taper might decrease the areas that have been brazed.

if that makes any sense to you.....it has me confuddled.

Cheers Murts I didn;t know that. So, the bits where the lugs join them selves may actually be thinner or actually a gap, and the braze then fills that gap?

i don't know, i'm just guessing.
but i do know, the cut-outs strengthen the lugs
and i'm not sure if the solder, runs all the way under the lugs, they are usually very tight fitting.

sorry forgot pics, doh!

I'm sure i've read somewhere that cutouts/shaping do nothing for the mechanical integrity of the lug and are just for aesthetics. But perhaps that was coming from a builder with boring lugs.
Surely the braze/solder needs to penetrate fully not a few mill' along the edges of the lug. See that dude on here whos bob jackson BB failed because they forgot to braze/solder it and that little fish woman, hippy's mate, who makes her own frames and has a story of a frame that failed that she sawed to bits to learn from her mistakes.

+

Barrie Witcomb told me that the ornate (ie point/cutout) bit of the lug isn't structural, and is only "dressed" to make it look nice.

I had a gap under the point of the fork crown lug, which he said:

(a) wasn't a problem

(b) was caused by the painter (enameller is too generous a term) shotblasting the fork for a second time having cocked-up the paint first time.

He also said it didn't matter that the forks rattled.

This is why I don't ride a Witcomb.

ha, B) caused by the painter............so, the lug had a gap because of the painter??? hmmm.

ha, B) caused by the painter............so, the lug had a gap because of the painter??? hmmm.

I think that was total bollocks too.

He said that the dressing wasn't structural (ie not brazed) so a bit of stray shot could remove it.

I told him it was total bollocks when he sent it back to Colourtech (again) to have another coat of paint applied without re-dressing the lug first.

This being after his new boyfriend told me the fork was unacceptable and a new one would be provided.

No worries dale. They know what I meant by 'filed lugs' now, tommy found a pic^^

I think I'm just gonna have a go. I'll need some decent files and something to keep the frame still. I'm guess I'm going to make it a continuous taper to the tips of the lugs, so I don't think I'll be filing right near the joins except at the very surface.

I think that was total bollocks too.

He said that the dressing wasn't structural (ie not brazed) so a bit of stray shot could remove it.

I told him it was total bollocks when he sent it back to Colourtech (again) to have another coat of paint applied without re-dressing the lug first.

This being after his new boyfriend told me the fork was unacceptable and a new one would be provided.

fnck!! stay away.
@skulls, good luck man,just keep an eye on it,.