What is the purpose of these holes?
 

This English built frame has two to three drilled holes in each of the bottom bracket shell ports and two in each side of the bottom head tube lugs. Look closely at the photo showing the bottom bracket shell; just to the rear of the rear cable guide you will find drilled holes. Look closely at the photo of the head tube; you will find drilled holes in the bottom of the lug. Is their purpose to minimize condensation in the tubes? BTW, the drilled holes don't go through the tubes. The drilled holes in the drop outs are for lightening I'm sure. The holes that I am speaking of are not to vent gasses, those holes are already there.

Thanks.

i can't see the holes that you are speaking of in the the pics (:50:), but they may be holes used to relieve outgassing during the brazing process or from temporarily pinning the joints before brazing. you may get a more thorough and/or accurate answer from a framebuilder.

on a second look i can see the holes in the dropouts. i've got some dropouts with holes like that too. i was told, or read somewhere, that they are there to encourage a secure grip between the dropout and the QR.

Which holes? The holesin the right dropout are both for looks and 'lightening' the frame (although removing that amount of steel does little to lighten anything)

There are also hole on the little brazon things to run the rear brake cable along the top tube, a cable guide/stop for the rear derailleur cable, a hole in the seatstay bridge for mounting the rear brake, fender eyelets on both the dropouts and fork ends.

http://www.bikeforums.net/attachment...4&d=1358271683

What I understood is that holes at the end of the frame tube were there to vent out expanding gasses during heating and brazing the frame together so as to keep the epanding gasses/pressure away from the area being brazed to avoid creating voids. bubbles or gaps in the brazing material. Not sure if they are always required as I've heard of some frame builders not needing them at all.....
BTW, some of the holes on campy dropout drive side faces were threaded and meant to support a "portacatena" chain hanger. A handy item when transporting bikes without their wheels on to keep the chaing from thrashing about, but I also wonder if it was worth losing the space (126mm) for the 7th speed on a FW sometimes..... I prefer a brazed-on chain hanger peg on the right seat stay instead because of that...

Chombi

I see the holes you are talking about. Very strange!

You mean on the right chainstay/lug? I wan't sure if they were holes, tool marks or something else. DYI cable routing?

If I understand the OP correctly he is referring to holes that were placed in the lugs (lower head tube lug and BB shell) before the frame was brazed. I see no reason to believe these are anything but aesthetic, but I am no frame builder.

If I follow your description and look at the photos, I think I see two holes drilled through the lugs, and through the stay sleeves of the bottom bracket shell, before the frame was made. Is that what you're talking about? The only purpose I can think of, for such holes, is an attempt on the framebuilder's part, to add a personal touch to the lugs. Something like a signature.

Is this a Hilary Stone photo montage? Do you have the frame? If you have the frame, I think some better photos are in order.

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edit.... Ah, I see the colonel has beat me to it. But we agree.

I didn't see the DT lug holes, too busy being a smartalec I guess, since there are holes in the BB area and the headlugs maybe for a BB mounted Dyno?

Colonel: I suspect that you are correct because I can think of no other sensible purpose other than to minimize condensation build-up. I think that I'll inquire on the frame builders section. Thanks.

Yes. Hilary Stone. I tend to agree with your conclusion. Thanks.

With those locations I'd say they're for routing an electric cable for the lights through the down tube. Right side and British align here. But the holes don't go through the tube wall, you say?

Thanks non-fixie but why two on top and two on bottom and on both sides of the frame? I'm more inclined with believing they are just for aesthetics.

Ah those must be some good old fashioned speed holes. I've got some in the hood of my car but never thought to put 'em on a bike ;)

Good point, at least on a steel frame. If there's a similar set of holes on the other side, you're probably right. If not, I'd like to stick for a bit with thinking they actually have some real function.

Rod brake stirrups:b

Ha! Maybe huh?

One can drill holes like this to allow for better filler penetration when you are brazing... as the holes are where the tubing meets the lug my thought is that the hole is in the lug itself and were not filled in post brazing.

A number of builders pin their frames with small nails to secure the position of the tube and lug and then remove that afterword... post brazing work covers this and unless you saw the naked frames you would never know these holes were there.

We use this technique when we are joining tubes with inner sleeves and when we build custom stems that have a bottom mounted bolt to secure them... we braze in a threaded sleeve and do this by drilling a small hole in the stem where it lines up with the insert as it is a very close fit and this allows for a complete fill of brass and requires less heating as the insert acts as a heat sink.

Other holes in the frame may be there to allow for outgassing while the holes in the hangar are there for speed... ;)

Sixty Fiver: Thank you. There are other holes for outgassing. The drilled holes are in the lugs. So, this was a procedure that was not carried to completion post brazing and has no function or purpose after brazing. Am I understanding correctly?

sorry, just an old simpson's reference... couldn't help muhself.

Ask Hillary. Maybe he has some ideas.

The frame arrived today so I got my first in-person look at it. Well, firstly it is a very nice frame even better than I expected. Secondly, there are several holes drilled in the lugs. The bottom bracket has three holes top and bottom on each side and the holes are in descending sizes. Same thing with the upper and lower head tube lugs. The holes in the dropouts are countersunk. IMO they look good. I think that we can now say that the whole thing of drilled holes in this frame is purely ornamental.

Thank you very much for your response. I learned something.

Are we getting better pics? Are they really holes, through both lug and tube, or just cutouts in the lugg?

I think they may be rust spots. We need a better picture.

I'm not sure what it is some people are not understanding. There were some ornamental holes drilled in the lugs before the frame was assembled. They're not rust spots and the holes aren't through the tubes. Even with the existing pics it seems fairly obvious to me.