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Fork Crowns

Old 01-30-22, 03:55 PM
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Andrew R Stewart 
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Fork Crowns

Recently I was motivated to go through my stash of fork crowns. The first photo is of the 1" steerer ones and #2 is of the 1.125" ones.



Way too many as you can see. Some I have never even considered in using, others had been favorites. A few I don't know the brand or model. It is time to move some along to new homes. Below is a shot of the available crowns (three, 1,16 and 19, are already spoken for).


Prices run from $10 up to $40 plus shipping. I can share more info and shots of specific crowns for the asking. Andy
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Old 01-31-22, 06:33 PM
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Quote Andy: "1,16 and 19, are already spoken for"

Those be MINE!

Thanks, Andy!
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Old 01-31-22, 07:01 PM
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I'm interested, too !

Hi Andy !

I'm interested in #5, 7, 11, and 17.

Let me know what they are going to cost and we can work out payment details.

Thank You,
Michael F in SF 94110
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Old 01-31-22, 07:52 PM
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Update- Crowns # 1,11,16,17,19 and 21 are gone. # 5 and 7 are pending. I hope someone will get some of the really old ones. Andy
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Old 02-01-22, 03:30 PM
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I'm trying really hard not to buy some of these, but failing. I need to see what I have before I PM.
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Old 02-01-22, 06:31 PM
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So, regarding building forks...

Silver or brass? It seems that fairly large gaps between the crown and blades are not unusual, so logic may suggest brass? How big of a gap is too big to use silver?

Edit: just searched around for fork blades and steerer tubes and it's slim pickens. Bought some Deda Zero Uno blades and a 1.25" steerer but had to search. This thread is timely, and some of you other guys with extra parts may want to do similar?

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Old 02-01-22, 08:24 PM
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I let the size of the gap tell me what to use but in the couple of forks I've built I had to open up sockets to get parts to fit. Big gaps weren't an issue.
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Old 02-01-22, 08:59 PM
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Now 5,7 and 8 are gone too.

Silver (as in the usual 56%) wants a .003 -.005 gap in a perfect world. Real life sees more and less in the same joint often. cast crowns tend to have better spigot or socket dimensional control but still most will need some fitting work as it's common to have the fit up too tight if left in factory condition. It is this gap filling aspect of a filler, along with a few other reasons, that I began to use brass/bronze more and more years ago. Andy
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Old 02-02-22, 01:20 PM
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Just for context, fork crowns are difficult for many of my framebuilding class students to braze completely right. It is one of the joints I have to sometimes take the torch to make sure the braze is done correctly. It can be catastrophic later if they aren't properly brazed. It is a critical area that must be done right.

The easiest crowns for a beginner to braze are full sloping ones like Andy's #15. The flame has access to all sides of the fork blade socket. The most difficult ones are the biplanes #5. It is challenging for a rookie to get their flame between the plates and heat everything evenly. That takes a much fancier flame motion. Another difficult to braze crown is #18. The inside of the fork blade is protected by the box structure of the crown making it difficult to heat that part of the blade enough to accept silver but not overheat the surrounding area too much in the process. I highly recommend amateurs assess their skill level and choose their fork crows accordingly. In other words not just by looks but also the difficulty level they are to braze.

After watching/teaching 100's of beginners to braze, I would not recommend brass brazing fork blades to a crown unless one is fairly experienced. The problem with fork crowns is heating everything evenly when some areas are much more inaccessible to a flame than others. What is likely to happen is overheating someplace trying to get brass to flow in somewhat inaccessible location. Overheating with brass can be a disaster because it is hurting the steel. Silver will work fine but you need to prepare the blades and socket properly. Typically the blades need to be squeezed in some direction so they kinda fit the crown. Once they are able to go inside, then I use a punch (with a flat end) hit with a small hammer to close the crown walls around the blade. I have a set of punches with different Ýs. I can't imagine building a lugged frame without those. One of the secrets of getting clean shoreline brazing is that the tube and socket walls are close together (so there aren't any gaps).

My solution for even heating is to use a large flame similar to a rosebud and hold it further back so it is a soaking heat. This allows all of the crown to come up brazing temperature at about the same time. I do have rosebuds but I have a lot of tips and my favorite when using propane (and essentially I have retired by acetylene and oxygen tanks) is a G-tec #2. This is a multi-flame similar to a Meco or Paige but much larger. The only difference between it and a rosebud (which has evenly sized holes) is that the center hole provides a nice sharp flame for cleaning shorelines. The side holes are a little smaller than the center hole. It is marvelous. BTW, G-tec makes adaptors/mixers so Smith and other brands can use Victor threaded tips.
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Old 02-04-22, 02:15 PM
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Got my crowns from Andy. Fast shipping and well packed. Thanks.

Thanks to Doug for the caution regarding heating flat top crowns. I'll watch closely and use silver, after closing up all gaps as tightly as possible. I may use brass for the steerer, just because that will be more tolerant to heating when brazing the blades.
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Old 02-04-22, 03:46 PM
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This is what I usually do, brass/bronze the steerer/crown and silver (fit up allowing) for the blades. Andy
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Old 02-04-22, 05:42 PM
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Is 9 for narrow blades?
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Old 02-04-22, 08:32 PM
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Yes, a boat anchor of a crown with lots of blacksmithing to make it look good. There were a handful of different companies that made this style, the Raleigh Professional of the early/mid 1970s was well known bike with such a crown style. Oh, and you will be using brass for the blade joints Andy
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