Framebuilders - difference in crown design/structure of steel forks - does this matter?

I've got a couple of nice Centurion road frames from the 1980's:
1984 TA Comp (http://www.unc.edu/~cupery/pics/bikes/Centurion_TA_Comp_frame/), Tange Champion #2 tubing, 63cm (ctt) seattube, 59cm top tube
1987 Ironman Expert (http://www.unc.edu/~cupery/pics/bikes/IMG_1520--Centurion_pink_bike.jpg), Tange #1 tubing, 64cm seattube, 58cm top tube
The crowns of their forks are significantly different designs, and I'm wondering if there is any functional difference or if it's only aesthetics.
The Comp TA has a very pretty-looking fork crown, with Tange Champion fork blades, whereas the Ironman Expert has Tange Cromoloy fork blades that are just welded to the steerer tube. I assume they're both plenty strong, probably comparable weight, and while the Comp TA's fork has slightly more tire clearance both forks can handle typical 28mm tires. The Comp TA's fork blades are narrower and prettier, and have more width-space for larger tires probably, but the bikes rear end won't take more than a 28mm tire so it's a moot point really.

I'm also curious about how the TA Comp's fork is produced - is it brazed? Forged in one piece? I can't really see any joints.
Here's pictures. First, the TA Comp in red, and then the Ironman Expert in pink.

http://www.unc.edu/~cupery/pics/bikes/Centurion_TA_Comp_frame/10_IMG_6874.jpg
http://www.unc.edu/~cupery/pics/bikes/Centurion_TA_Comp_frame/IMG_6851--Centurion_fork_crown.jpg
http://www.unc.edu/~cupery/pics/bikes/IMG_7135--Centurion_welded_fork.jpghttp://www.unc.edu/~cupery/pics/bikes/IMG_7133--Centurion_welded_fork_side.jpg

The cast crown of the red forks is brazed to the tubular legs. Painting hides the seam.

The pink forks are tig welded. Plenty strong, just a little lacking in the aesthetics dept.

I had an Ironman Expert, 'cept mine was white. It was my first 'serious' road bike. Ahhh, those were the days.

This type of crown has tangs that fit inside the fork blades and after brazing the joint is filed smooth and there should be no gap or line showing.

It’s a pity this one has the brake hole drilled off center, it won’t affect the ride or the braking, but it is sloppy workmanship

It’s a pity this one has the brake hole drilled off center, it won’t affect the ride or the braking, but it is sloppy workmanship
Agreed. At least its unnoticeable when the brakes are installed. And it looks a whole lot better than the welded design, IMO.

Is the pink fork lighter? That style has better material continuity and less junk in the crown. Admitedly the traditional design looks better, but that doen't mean it is better. On a cost basis the unicrown (pink) design can actually be pretty expensive and the prebent fork legs are expensive to buy compared to the tapered straight tubes, and the skill or jigging required to cut the miters is greater. Of course with the unicrown you don't need to buy the crown. In the Nova stuff I get, the Unicrown fork legs are 35 bucks, and the separate crowns are 15 while the fork legs are 20. The skill of tig welding is greater, though once mastered it's faster to churn out.

Is the pink fork lighter? That style has better material continuity and less junk in the crown. Admitedly the traditional design looks better, but that doen't mean it is better. On a cost basis the unicrown (pink) design can actually be pretty expensive and the prebent fork legs are expensive to buy compared to the tapered straight tubes, and the skill or jigging required to cut the miters is greater. Of course with the unicrown you don't need to buy the crown. In the Nova stuff I get, the Unicrown fork legs are 35 bucks, and the separate crowns are 15 while the fork legs are 20. The skill of tig welding is greater, though once mastered it's faster to churn out.
I'm going to weigh them later today. Will try to get back on this. The info about construction methods is really interesting, thanks.

Is the pink fork lighter? That style has better material continuity and less junk in the crown. Admitedly the traditional design looks better, but that doen't mean it is better. On a cost basis the unicrown (pink) design can actually be pretty expensive and the prebent fork legs are expensive to buy compared to the tapered straight tubes, and the skill or jigging required to cut the miters is greater. Of course with the unicrown you don't need to buy the crown. In the Nova stuff I get, the Unicrown fork legs are 35 bucks, and the separate crowns are 15 while the fork legs are 20. The skill of tig welding is greater, though once mastered it's faster to churn out.

I have a theory on this. I don't think welding is that much faster than brazing in a production environment. However, it's safer, less messy, and more importantly it's quantifiable - you can read the settings on a TIG machine (and program some of them) and visually inspect the join much easier than a brazed join.

I have a theory on this. I don't think welding is that much faster than brazing in a production environment. However, it's safer, less messy, and more importantly it's quantifiable - you can read the settings on a TIG machine (and program some of them) and visually inspect the join much easier than a brazed join.

Brazing requires a water soak cycle to remove the flux. TIG does not. That's one reason for TIG being faster and cheaper.

The unicrown welded fork from the Ironman is 1cm longer, but it's the lighter of the two. Barely.
The pink Ironman Expert fork, welded unicrown construction, weighs 1 lb. 12 oz.
The red TA Comp fork, brazed and beautiful, weighs in at 1 lb. 14 oz.
So it's a difference of 2 oz., and the brazed fork is slightly heavier despite having a 1cm shorter head tube.

Brazing requires a water soak cycle to remove the flux. TIG does not. That's one reason for TIG being faster and cheaper.

In a production environment it's not an issue. Heck, Aluminium has to be solution heat treated (for 6061) and artificially aged in a massive oven and that's not a barrier.

The act of brazing in and of itself is not why TIG is more popular that brazing. It's everything else. Less parts inventory. Less processes. Quantifiable, repeatable construction.

You have to realise that in a production environment where you're producing 10-40k frames a year, things like 'washing flux off' isn't a dealbreaker. How you stick two tubes together is more a result of market demand and marketing strategy than anything else, and if demand for lugged steel frames somehow rose in the Western world overnight, you'd be able to buy cheap, good lugged frames the next day.

Interesting observations. I'm not a fast brazer myself, I just do it here and there. I was impressed at how long it takes Tim to braze joints in his videos, and by the times he cites for pro and amateur eforts, both of which seem long.

I think you are right about flux, aircraft stuck with gas welding until the OSHA pushed them out of it. The toxicity of the flux was the problem. May be the same thing with the blazing flux. Of course that too is a lessor problem in a production setting.

I was really thinking custom frames in my coments, but you are right to mention production given the frames in question. In production settings brazing can be very fast. I have seen video where all the tubes in a frame are mounted in a jig the whole thing is heated with propane jets every which way as internal slugs of bronze are drawn out.

You have to realise that in a production environment where you're producing 10-40k frames a year, things like 'washing flux off' isn't a dealbreaker. How you stick two tubes together is more a result of market demand and marketing strategy than anything else, and if demand for lugged steel frames somehow rose in the Western world overnight, you'd be able to buy cheap, good lugged frames the next day.

Number one reason that drove lugs out of the production envinromnent was cost. Even if there is not a lug present, brazing IS more expensive that TIG because the material costs are higher (brass/silver is not cheap) and brazing requires more resources: labor and equipment. Regarding the economy of scale with mass production, my experience is that higher management is always looking for ways to cut costs. If big production numbers are involved, the motovation is increased exponentally. For example, if you are making 40k frames a year and you find a way to save $1 per frame that totals $40k per year which = Nice BMW 5-series car for the CEO. The only way extra dollars are spent in production is when people are willing to pay extra dollars for the end product.

Yeah, welding robots can do TIG seams at over 2-ft/sec. No wasted time waiting to heat up the joint evenly and waiting for the brass to flow...

Yeah, welding robots can do TIG seams at over 2-ft/sec. No wasted time waiting to heat up the joint evenly and waiting for the brass to flow...


True, but a welding robot can never ever make the beautiful beads that some of the best TIG welders in the world can make. Look at a Moots, or Seven, Merlin, or Litespeed. No way a robot is going to replicate that. Reason is because there is too much variation and control during the TIG process that only human hands can do if you want the smoothese quality. You are absolutely right though that brazing takes a LOT longer to do than TIG.

Yeah, for a human, doing TIG compared to brazing is still significantly faster. The Giant frames are robot-welded, looks darn good. However a human can actually do a weld that's smooth like brazing, without a pattern of continuous droplets.

What about that Centurion fork that Tim posted, I wonder if that was a robot or humans? I guess you'd have to know exact which contractor WSI used for that particular batch, they had numerous suppliers over the years.

I think you are right about flux, aircraft stuck with gas welding until the OSHA pushed them out of it. The toxicity of the flux was the problem. May be the same thing with the blazing flux. Of course that too is a lessor problem in a production setting.Unless things have changed in the last few years, the FAA won't approve any airframe with a brazed joint of steel tubing. So, why would there be any flux involved? I took 120 hours of airframe welding classes and we were taught that the only time you use flux with gas welding was for aluminum, stainless or similar situations.