Wednesday, December 15, 2010

Rollercam makeover...

As the shop is in a bit of disarray at the moment getting ready for the move, I've been working on chipping away at the long list of small projects that have been occupying the shelves, many for a number of years.  Most have not been particularly blog worthy, but since we have a large number of vintage folks here, I thought I'd share this one. 

Here we have a vintage Fat Box crown fork with Reynolds blades and Campy drops that belongs to Michael.  This guy is a candidate for removal of the canti studs and replacing them with Roller cam bosses...but first we need to check that it will meet the dimensions necessary.

It's been a while since I worked with RC's, so I wanted to confirm my notes in my little cheat book of chicken scratch with someone who is a bit more familiar with the genre.  A quick conversation with Steve Potts (thanks a bunch!) confirmed the necessary dimensions and we were all set to move forward.

Michael's Fat fork, all stripped and ready for action...
 To begin removing the cantis, I place painters tape on the adjacent edges of the boss, so when I begin to cut and file I can visually see if I begin to intrude on the surface area of the blades around the boss.  This little tip keeps me from undercutting the tubing and reminds me to take it slow and easy.
 With the tape in place, I begin to remove the mass of the boss with a grinder and cut off blade.  I'll then step down to a Dremel with an abrasive disc, a Dyna file, and finish off with a hand file...
 One blade done, touch up on the next ready to go...
 With the material removed and the blades filed, there are two small dents in the tubing where the points of one canti boss ended, more than likely from the thin wall tubing succumbing to the forces of braking through the years.  I'll fill these with a bit of silver before paint.  Now it's time to locate the roller cams.  Of all the brake types, these are the most finicky to have positioned correctly.  Not only do you need to consider the axle to boss center line, lateral center line offset dimension, and stand off from blade for cable/headset clearance, the superior/inferior angle is critical for correct pad to rim alignment.  I made up a quick fixture to hold everything in place at the correct dimensions and tacked them in place...
 Next up, sort through the box of Roller cam parts to test fit a wheel...
 Using a modified linkage brake that Hubby had played with for the test fit, I want to insure that I've got the correct pad to rim angle throughout the motion of the brake and that there are no interference issues...
 In this case, everything lined up well.  The original box fork bosses were tig'd in place, so rather than brass brazing these, I followed suit to keep with the flavor of the period.
I'll get this guy into the powder booth for some sweet 80's Fat yellow and it'll be ready for Michael's next vintage build.

cheers,

rody

1 comment:

Brandon said...

I don't know why, but I think projects like these are among the coolest things in the world.