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 Post subject: Building the Fat fork...
PostPosted: Fri Apr 14, 2006 11:50 pm 
BoTM Winner
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Joined: Sun Oct 23, 2005 7:22 pm
Posts: 742
Location: Wooster, Ohio
Hey guys,

From the interest I've received through email I thought everyone would enjoy a quick pictorial trip to describe how Alan's (Ti fat man) fork came to be. I did not take a lot of pics, but have a few so Alan could follow the progress.

First step was sourcing original materials. The Campy forged dropouts were cast in an Italian factory that ceased production two years ago. The availability of these has become rare as milk from boar's tits. Luckily, I was able to pry two pair out of a fellow framebuilder :D .

I chose to go with slightly heavier wall tubing than the original BOI to stiffen the fork up laterally as I always thought it was a bit flexy. The steerer tube and crown ring were original equipment from a west coast supplier (promised not to name names 8) ).

I built a custom fork fixture for the geometry of the segmented fork, adjustable for different lengths and rake to accomodate pre-suspension and suspension corrected lengths.

The most difficult aspect of the fabrication is the compound miter that joins the steerer tube and the legs, requiring precise machining on a very small piece. Had to make another jig to hold this crown piece in the mill to make the cut.

The teardrop tabs were hand cut and silver brazed on...a requirement for the original tubing but mere historical accurate detailing on these.

Final clean up and paint finish it off.

I ended up building two forks; Alan's Big One Inch and a Yo Eddy for my project.

Enjoy the pics...

cheers,

rody
Groovy Cycleworks


Attachments:
fork fixture smaller.JPG
fork fixture smaller.JPG [ 90.97 KiB | Viewed 4122 times ]
Yo tubing.jpg
Yo tubing.jpg [ 66.79 KiB | Viewed 4122 times ]
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 Post subject: more pics
PostPosted: Fri Apr 14, 2006 11:54 pm 
BoTM Winner
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Joined: Sun Oct 23, 2005 7:22 pm
Posts: 742
Location: Wooster, Ohio
more pics


Attachments:
dropout offset2.jpg
dropout offset2.jpg [ 57.67 KiB | Viewed 4120 times ]
dropout cut 2.jpg
dropout cut 2.jpg [ 57.65 KiB | Viewed 4120 times ]
Bigoneinchprogress.jpg
Bigoneinchprogress.jpg [ 47.75 KiB | Viewed 4120 times ]
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 Post subject: more pics
PostPosted: Fri Apr 14, 2006 11:57 pm 
BoTM Winner
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Joined: Sun Oct 23, 2005 7:22 pm
Posts: 742
Location: Wooster, Ohio
more pics


Attachments:
Bigoneinchprogress2.jpg
Bigoneinchprogress2.jpg [ 70.2 KiB | Viewed 4118 times ]
Alan's fork back1.jpg
Alan's fork back1.jpg [ 78.9 KiB | Viewed 4118 times ]
Alan's fork side1.jpg
Alan's fork side1.jpg [ 69.12 KiB | Viewed 4118 times ]
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 Post subject:
PostPosted: Sat Apr 15, 2006 12:10 am 
Mr Darcy
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Joined: Wed Oct 26, 2005 8:36 pm
Posts: 5687
Location: Bicester
awesome :D

Its great to see some of the workings behind what goes into building this stuff. I know roughly what goes on, but really good to see it in detail. Are the legs formed somehow? Or am I looking at the crown tubes? Do you do that yourself?

Cheers Rody


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 Post subject:
PostPosted: Sat Apr 15, 2006 8:53 am 
Concours Judge
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Joined: Wed Jul 06, 2005 3:59 pm
Posts: 8171
Location: a proper EU country
Well, that's nice!

Nice machinery you got there too btw. I don't remember any of my builders sending me an extensive footage of the progress.

Keep up the good work!

- Melvin


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 Post subject:
PostPosted: Sat Apr 15, 2006 10:15 am 
Retro Guru
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Joined: Mon Oct 10, 2005 12:07 pm
Posts: 2676
Location: 52 Festive Road. (Nr. Lincoln)
Excellent work Rody, I really like what you've done there.

How long did it take to build them and would subsequent forks be quicker to build?

Any plans on making more?

:D


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 Post subject: Disc mounts?
PostPosted: Sat Apr 15, 2006 1:11 pm 
Retro Guru

Joined: Tue Sep 27, 2005 8:52 pm
Posts: 546
Location: South West
Very interesting indeed!
Not retro or period correct but I wonder if the design could accomodate disc mount tabs?


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 Post subject:
PostPosted: Sat Apr 15, 2006 1:26 pm 
Retro Guru
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Location: 52 Festive Road. (Nr. Lincoln)
Tangent, wash your mouth out with soap!

Just kidding.... on-one do (or did) a very similar Ti fork that was disc only (there's one in my garage) They still do a steel version 5 piece superlight fork, disc and V.


Attachments:
superlightfork_1.jpg
superlightfork_1.jpg [ 19.53 KiB | Viewed 4064 times ]
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 Post subject:
PostPosted: Sat Apr 15, 2006 1:31 pm 
BoTM Winner
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Joined: Sun Oct 23, 2005 7:22 pm
Posts: 742
Location: Wooster, Ohio
In answer to the questions...

Quote:
Are the legs formed somehow? Or am I looking at the crown tubes? Do you do that yourself?


Gump...everything is handmade. The pics of the mitering is showing the offset cut made to form the scallop miter in the dropout. The cut is made, dropout inserted and tacked to the flat/remaining portion of the tube, a scallop cut piece of tubing is then inserted to match the inside radius and everything is then welded/silver soldered together to form the finished dropout.



Quote:
How long did it take to build them and would subsequent forks be quicker to build?

Any plans on making more?


Steve...the original forks took a loooong time as I had to create a new fixture and work out the kinks to get the process down. A finished fork would now take me about 10 hours with paint to build one at a time.

As for making more, this was a personal project for my Yo, as I wanted to build my own rather than search for a used fork. I offered one to Ti Fat Man as I was touched by his lament of selling the original and having trouble sourcing another NOS. Morally, I would not want to profit from another's design and success (Chris Chance). As discussed numerous times on Fat Cogs, I don't know what the legal restraints would be as trademarks and patents are suspect to be expired. Would I build another for a bleeding heart desperate to complete a project....perhaps.


Quote:
Not retro or period correct but I wonder if the design could accomodate disc mount tabs?




Tangent...with the increased wall diameter of the .035" tubing the fork would easily handle the rigors of disc work.

cheers,

rody


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 Post subject:
PostPosted: Sat Apr 15, 2006 1:32 pm 
Retro Guru

Joined: Tue Sep 27, 2005 8:52 pm
Posts: 546
Location: South West
Ha Ha, Gotta have 1inch steerer ... guess some disc brakes designs could be considered retro now...wouldn't want to ride them tho'!


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