1950/51 Schwinn Continental - Large Frame (23") - Black

[Schwinn Sales West]

I always understood that the whole point of brazing a frame is that it's less heat than welding. Any high carbon steel can get hard if it's heated enough, and as a general rule the harder something is the more brittle it is, so hardening is good for cutting tools and wearing surfaces, but not good for frames. Welding works well on low carbon steel because low carbon steel doesn't get hard, but it's not as strong as high carbon steel.
On the other hand I think the Super Sports and Sports Tourist frames from the '70's were silver soldered instead of brazed, so maybe even brazing was too much heat. The only welding I had was an introductory course many years ago, so there's a lot I don't know. But I read somewhere that "silver solder" is actually mostly nickel, the name comes from "German silver", an old name for nickel. If somebody on here knows more about this, don't hesitate to enlighten me.

LOL, your both correct, but it gets confusing.

Welding (gas, or electric like MIG or TIG) joins the steel metal by melting the steel at a high temperature and adding a filler rod. Welding is best used for joining thicker materials, let's say 1/8" or thicker. Because of the high temperature required it's a pretty aggressive means to an end but produces a very strong joint.

Brazing joins metals at a lower temperature using Brass/Bronze as the filler and a flux to make it flow. The metal does not need to be brought up to a steel melting temperature for the filler rod to melt. Since the Brass/Bronze filler rod is a soft material it serves well in sanding/grinding to make the smooth transition of the Filet brazed joint. The down side is that it is "very easy" to undercut the filet brazed joint when finishing the brass joint area and grind/cut into the metal tube reducing the wall thickness. Schwinn Chicago had occasional problems with this issue. Some of the "hand made" BMX STINGS, and the Giant produced mountain bikes had "undercutting" issues on filet brazed frames. Giant sent a team of inspectors to each of the four Regional Distribution Centers to sonic test their frames to determine which had to be replaced before they were released for shipment to the dealers. I'd bet the filet brazed frames @cyclingday had problems with were frames that got "undercut" at the factory.

Lugged frames have the advantage of using the lowest temperature of all three frame joining methods. The low temperature allows the use of very thin wall frame tubes, and the joint is done "almost like" sweat soldering a copper water pipe, but of course on chrome moly steel it is done with silver solder. Because the joint is done at a lower temperature it also makes it easier to replace a frame tube for a repair.

John

 

[Oilit]

LOL, your both correct, but it gets confusing.

Welding (gas, or electric like MIG or TIG) joins the steel metal by melting the steel at a high temperature and adding a filler rod. Welding is best used for joining thicker materials, let's say 1/8" or thicker. Because of the high temperature required it's a pretty aggressive means to an end but produces a very strong joint.

Brazing joins metals at a lower temperature using Brass/Bronze as the filler and a flux to make it flow. The metal does not need to be brought up to a steel melting temperature for the filler rod to melt. Since the Brass/Bronze filler rod is a soft material it serves well in sanding/grinding to make the smooth transition of the Filet brazed joint. The down side is that it is "very easy" to undercut the filet brazed joint when finishing the brass joint area and grind/cut into the metal tube reducing the wall thickness. Schwinn Chicago had occasional problems with this issue. Some of the "hand made" BMX STINGS, and the Giant produced mountain bikes had "undercutting" issues on filet brazed frames. Giant sent a team of inspectors to each of the four Regional Distribution Centers to sonic test their frames to determine which had to be replaced before they were released for shipment to the dealers. I'd bet the filet brazed frames @cyclingday had problems with were frames that got "undercut" at the factory.

Lugged frames have the advantage of using the lowest temperature of all three frame joining methods. The low temperature allows the use of very thin wall frame tubes, and the joint is done "almost like" sweat soldering a copper water pipe, but of course on chrome moly steel it is done with silver solder. Because the joint is done at a lower temperature it also makes it easier to replace a frame tube for a repair.

John

I never considered the possibility of "undercutting" the frame tubes while smoothing the filets, but that makes sense. Thank you for a clear and drama-free explanation! (No long spiels about how you were first but no-one appreciates your genius, unlike another member who I won't name).

 

[rennfaron]

The only hesitation I would have with getting the parts is if there's damage to the frame. The seat mast should be checked for the miserable hairline cracks these frames sometimes form around the brazing at the seat stay to seat tube joint.

@SirMike1983 Took a close look at that area and don’t see any issues (no crack, no paint chipping/lifting). Looks pretty solid. And considering this may have been run pretty hard over the years, assumed by all the swapped parts, this is good news. And by a bigger (taller) rider. (That said, it may not have been run that hard, considering the decals are in such good condition)

 

[SirMike1983]

Sounds like a good project for a proper build up. Not easy to find one of those.

 

[DKB]

Very nice find. You're particularly fortunate to get the FM with the SA wingnuts. Those are extremely cool.

 

[juvela]

I think those are the first "Clement Albione" rims I've seen. They look aluminum, correct? Since they're 27" they probably had to change the brakes along with the rims to fit, so somebody put some thought and effort into that build. What period are Clement Albione rims? @juvela, have you seen this bike?

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product current late 1940's & early 1950's but have no start/stop dates

Help ID rim logo 24" | Vintage Lightweight Bicycles

Picked up this unusual rear wheel and having trouble identifying the brand from the sticker. Anyone recognize it? The rim is a 24" tubular 36 hole laced to a low flange BH Airlite double fixed hub. So it's basically a vintage kids track racing wheel. Willing to sell/trade once I get it cleaned...

thecabe.com

[scroll to post number ten]

https://flic.kr/p/cnYC7m

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[Oilit]

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product current late 1940's & early 1950's but have no start/stop dates

Help ID rim logo 24" | Vintage Lightweight Bicycles

Picked up this unusual rear wheel and having trouble identifying the brand from the sticker. Anyone recognize it? The rim is a 24" tubular 36 hole laced to a low flange BH Airlite double fixed hub. So it's basically a vintage kids track racing wheel. Willing to sell/trade once I get it cleaned...

thecabe.com

[scroll to post number ten]

View attachment 1853842

https://flic.kr/p/cnYC7m

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So it sounds like this is most likely an older build, dating to when the bike was new or close to it. It would be interesting to know who put this together, but that may be impossible at this point. Thanks!

 

[SirMike1983]

So it sounds like this is most likely an older build, dating to when the bike was new or close to it. It would be interesting to know who put this together, but that may be impossible at this point. Thanks!

I think that is very likely. It would have been a kind of exotic wheel set in the 1950s - something a little higher-end for a club bike after the move to 27 inch wheels.

 

[juvela]

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hello again Tin Man,

forgot to mention above that this model of rim was also produced with French language labeling - "JANTES CLEMENT"

me guess, and its only a guess, would be that both the Clement wood and the Clement metal wheel rims would have been contract produced

they represent a logical adjunct to their manufacture of tyres

if any readers would like to explore this further it is the sort of topic which is likely to have been discussed on the Classic-Rendezvous email list and/or on Italian language cycle fora

hope this helps the question a bit


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[rennfaron]

So it sounds like this is most likely an older build, dating to when the bike was new or close to it. It would be interesting to know who put this together, but that may be impossible at this point. Thanks!

@Oilit Thanks for your prompt on this and usually I like to get those details, but other things were going on and was just glad to get the bike and have it here. I went back to the seller and they said it was her father-in-law's bike and he was a Schwinn salesman. It was up in their attic since 1991. That's cool! Seller sold it as a "1970s Schwinn Continental." Obviously her FIL knew what that bike was and just wanted to keep it going. If up there since 1991 and was outfitted way before that, it was probably just a solid frame set he could keep going with.