SpeedofLite 

gugie 

Interesting that the author advised against "tiddly bits" brazed in the middle of thin wall tubing. At the time brass (bronze) brazing was the medium used, requiring a fairly high temperature, so tubing was easily "overcooked". From his description of "very tricky fluxes" for silver brazing, I can only guess that the flux I use today was not available BITD.

madpogue 

I was just amused by the reference to top-end bikes as being "multi-hundred-dollar".....

unterhausen

In 1973, a paramount was just over $400. Too lazy to check an inflation calculator, but I think that's less than $2k

daka

I didn't see it mentioned in the article but can someone comment on the virtues/vices of hearth brazing vs. torch brazing? I think it's obvious that hearth brazing requires pinning as opposed to fixturing, but is one method of heat application better for the tubes/joints than the other?

79pmooney

"Multi" now often being several dozen. But that term does describe what I paid for my namesake.

unterhausen

The tubing of the day was not heat treated, so hearth brazing works fine. Most builders still pin or tack and finish the frame build out of the fixture, so there would be nothing stopping people from hearth brazing. In fact, I know there are people still doing it.

SJX426 

@daka - its about heat control - soak/cooling as it impacts material crystalline structure. It is material mechanical properties driven. Some materials don't like a high delta of temperature in short distances. The other advantage in preheating is the workman doesn't have to wait for the joint to heat up from ambient temperatures, improves production labor time.

Trakhak

Paramount = non-inflation-adjusted $175 when I started racing, in 1964.

unterhausen

I was wrong, that paramount from 1973 would be about 2500

L134 

And, who was this southern California craftsman?

repechage

One of the bike magazines did an article on Holdsworth, there was an image of hearth brazing a seat tube to a bottom bracket. That was the only image of that. the fire bricks were placed so the only items I could see brazes that way would be that, the fork crown to steerer, and maybe the chainstays to the dropouts.

repechage

At the time, Art Stump, Freddy Parr, and Jim Holly were the one man shows, G P Wilson, but he built very few. And Hood, again very few.
Freddy was an early experimenter is oversized tubes on Sprint bikes.

A bit later Brian Baylis / Mike Howard as Wizard.

L134 

Kieth Lippy? Bill Holland? I’m pretty sure Lippy used silver. Just curious. As much as I enjoy reading these articles, I’m struck by how little they actually say considering how long they are. That reference is useless without a name, then and now.

unterhausen

Pretty easy to do every joint in a hearth. Not sure everything was done that way. I always liked the way Merckx did it with the pre-heating stations.

Doug Fattic 

I went to learn how to build frames at Ellis Briggs Cycles in Shipley, West Yorkshire in 1975. Compared to most other UK builders I visited, their equipment was more clever and sophisticated. Their fixture was based on a cast iron alignment table. They brazed the major joints by hearth brazing but while I was there switched over to doing them with a oxyacetylene torch. The very 1st frame I made was hearth brazed.

After assembling the front triangle on the cast iron fixture, the tubes/lugs were both spot brazed and pinned together. The unit was taken over to the hearth table where the frame was hung over and surrounded by fire bricks. The natural gas nozzle was huge and the flame was augmented by oxygen from a squirrel cage blower. Both head lugs would be done at one time. Of course this giant flame heats the tubes fairly far up from the lugs. I would hold the brass rod in a holder to keep my hand away from all the heat. The flame didn't take much movement on my part and the hot metal would easily absorb the brass by capillary action.

The good news is that hearth brazing applies heat evenly so the frame is not thrown out of alignment like might happen by doing one part before another. However neither was it perfect because we would always have to make adjustments on the alignment table before doing another joint. Andrew (Ellis Briggs journeyman builder at the time) quit doing hearth brazing in favor of doing it all by oxyacetylene torch. The problem was that the lug shorelines had to be touched up with an OA torch after hearth brazing so he figured why have a 2 step process when it could all be done at one time.

When I came back to the States I immediately started brazing with silver with an oxyacetylene torch. It melts at 400 degrees lower temperature - which is an obvious advantage to both tube and alignment. Now I use propane instead of acetylene. The oxygen is supplied with an oxygen concentrator (the machine that normally supplies oxygen to damaged lungs).

Last ride 76 

Doug,
Before the pandemic, I used to think about getting an oxygen concentrator, for the couple times a year I get lung infections, having had severe asthma for many years. Obviously now is not the time, but propane and a concentrator would be sufficient to not need an oxy/acyetelene unit? That's pretty cool.
Best regards, Eric

Doug Fattic 

Yes propane combined with an oxygen concentrator works great. BBQ propane tanks can be bought zillions of places at all hours. Neither is its transportation and sale restricted like acetylene. It isn't sooty either and much much cheaper. What makes propane work better for brazing frames are propane specific multipart tips. Paige Tools a source for jewelry makers listened to our pleas and made adaptors for their tips that work for Smith AW1A and Victor J-28 torch handles.

M&M Medical in Beaverdale, PA refurbishes concentrators for general use sale. A Devilbiss model 525 costs $300 with a 3 year warranty. I just called them last week and they have them back in stock. That model is my favorite because it has more output that other manufacturer's 5 liter per minute models. Some of my frame building class students have gotten concentrators on Craigslist or wherever for less but of course that is a matter of luck. They are rare during the pandemic because more concentrators are needed for damaged lungs.

Last ride 76 

I'm willing to hold off for a bit. I figure there's a chance someone else will need it more than I do. But that is really cool, and great news for the future. Not cost prohibitive either, especially as it will do double duty with me. I currently use a mapp torch for the few things I do, and really didn't want to get into an oxy/acy rig. at this point. Thanks for the detailed info and sources!
I will keep collecting my bits
Thanks again, Eric

PS I hated those stringy bits of black stuff floating about. Forgotten all about them.

unterhausen

Doug, when they were hearth brazing, how did they do the rear triangle?

Good to hear than M&M has concentrators, maybe I'll buy one

Doug Fattic 

The rear dropouts were 1st brazed into chain stays in preparation for hearth brazing that unit into the bottom bracket shell with the front triangle. After the front triangle was spot brazed and pinned, the chain stay units were inserted into the BBS sockets. Using a true rear wheel and a straight edge they were slide in and out until the indicators showed the wheel centered. An adjustable T tool attached to the seat binder bolt and dropouts set the angle of the chain stays to the seat tube. After pinning them to the shell, the entire BB area was hearth brazed.

Oxygen concentrators are great. It is an endless supply of oxygen that doesn't require refill trips or expense. My tanks always seemed to run at 4:59 on Friday afternoon. It does take a couple of minutes for the concentrator to purge its holding bladder and hose lines with almost pure oxygen. That means I turn it on when I start fluxing the joint. While some of my students have found used concentrators for under $100, that is pure luck. A local student has been watching Craigslist for a whole year without any luck finding one that cheap. Most personal sales cost at least $300 or more. He figured getting a refurbished one with a 3 year warranty from M&M made more sense. Ask for a Devillbiss model 525. I also scored a couple of almost brand new Invacare Platinum concentrators and they work fine with normal tips but don't have as much output for when I want to use a rosebud.

non-fixie 

Interesting to read about the American take on what constitutes a top-end bike. In my area there would have been only one question: does it win races? I don't think anybody here was interested in ornate lug filing or interesting-looking dropouts. A top-end bike was a race-winning bike, and such a bike needed to be fast and reliable. And cheap, if possible.

Biketiger

Fascinating article - thanks for sharing. I learned a lot. Its interesting he states that more than half the way a frame rides is due to the technical skill of the builder. I don't know how he determined this performance ratio, but I do think that tubes make a huge difference. All my Columbus frames feel very different than the Reynolds 531 I've got and the Reynolds straight guage frame I had felt so dull in comparison to the double-butted Reynolds frame, I got rid of it.
Given the choice of a bike from competent builder with top quality steel or a master builder with plain guage - I'd go with the former!