How to save badly drilled track fork
 

Hi there,

Looking for some advice about my options with a badly drilled fork brake hole on an old Geoffrey Butler fillet brazed track frame I just bought. The paint was proper nackered but it had super nice fillet brazing and going cheap on eBay so I couldn’t resist. It was looking very sad. I have built it up with tubular rims on an old single speed torpedo hub (very fun to ride). One day I’ll repaint it and make it beautiful :)

So it seems the previous owner has drilled the hole in the fork way too low, and actually slightly angled down meaning the springs of the calliper I tried actually just dragged on the tire. It measures around 34mm reach.

my options as I see it:

1. Just accept 2 rear brake system, seems dangerous though. (Calliper and coaster brake)
2. Fill the hole with steel bar, braze in place, drill new hole 3/4mm higher. I think just for the front hole, so solve the tilting down, and slightly tilt back up.
3. Buy new fork :(
4. Maybe ultra short callipers do exist. Shortest I have found are diacomp aero, but even they are not quite enough.

I think I most want to go with 2, filling the hole and redrilling, but keen for suggestions!

will
https://cimg3.ibsrv.net/gimg/bikefor...1125d7578.jpeg
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If the paint is already ruined in that area, I would fill the current hole via brazing and re-drill.

I like the "fill with rod, braze and re-drill" option, myself, but it's not my fork. You could try a brass rod rather than steel, not sure if that would be easier to solder/braze versus steel, or not. Worth doing even if you don't re-drill for a front brake (but I would)...nice looking track frame!

I like the "fill with rod" option. If it doesn't work you can always try the two rear brake (if you are not confident with the coaster brake alone).

I would only replace if I were going to paint the whole bike anyway.

Use a drop bolt upside down. might have to use a Campagnolo short reach spring on a standard reach caliper. Path of least resistance.

Thanks for reply guys.

Glad there is a strong consensus on fill-braze-redrill. The paint being so damaged already in that area is basically telling me to do it!

im comfortable riding just with a coaster brake and if needs be that’s how it’ll stay., did a ride today with it but annoys me abit having to be ‘careful’. Wouldn’t be able to do a good emergency stop from speed. My first bike with tubulars too so really wanna fly around on this thing.

will

5. Clamp-on Keirin caliper.

A 1/4" steel rod would probably fill the hole nicely. I'd worry about the drill bit wandering into the softer brass if a brass rod was used.

I agree that the"proper"fix is to fill the hole with steel, brazed in place, and then drill it right with a drill press.

Another option is a Resilion cantilever brake. Period correct, British, excellent braking, and awesomely funky. Unfortunately those are hard to find.

Another another option is a Philco "central pull" brake, also British and also period correct, and also awesomely funky, just totally sucks as a brake. Fortunately those are hard to find.

This.

https://www.retro-gression.com/produ...-brake-caliper

You're not going to have the same braking ability as a drilled fork, but it'll get you riding quick for a relatively small expense.

Doubling up on the rear drum/caliper brake sounds iffy.

Could you safely tig weld it without overheating?

You can wrap the fork blades and the steer tube with wet towels. But, you would end up awfully close to the steer tube.

If you do weld or braze a rod into it, I'd do two short pieces from the steer tube to the outer edge (plus enough to file down). Penetrating just past fully through the steer tube.

What reach is it? I've got a short brake.

I was thinking that too.

An idea if you go the steel rod and braze route. Before doing that, file very carefully a sharp "V" along the top of the existing hole deep enough that there will a straight path of pure braze clear across the crown that will serve a a guide for the drill bit. Now, drill that first hole with a small drill. Use that as a pilot.

(Caution - just thought this up. I haven't done it nor am I a framebuilder. I would set up a jig to aligh the file at both ends of the hole. How? Sorry, not there yet,)

Interesting challenge.

Ben

Thanks for more suggestions. Love the Resillion callipers! Will keep my eye for a good buy in one of them anyway. Luckily I have a friends Dad who is very pro at all things metalwork, so trust him to help make a good job of it. Will post back pictures when it’s done (maybe a couple of weeks)

Looks like you've got a good solution already, but I'll still suggest this for anyone else who has an issue like this or has an undrilled track fork.

Seisakusho Detachable Front Brake Mount

https://cdn.shopify.com/s/files/1/11...g?v=1527485571

I agree with the posts above that suggest filling the hole with a mild steel rod and brazing it in with silver. The only thing I would add is that I would start the new hole with a "center drill". Google can picture what that is. They are designed so that they can start drilling a hole without the bit wandering off center. Regular drill bits will wander towards a softer metal side. Probably using a #3 center drill that has a diameter of .246" (I'm too lazy to check to confirm). That is slightly larger than 6mm. I use my Bridgeport vertical milling machine so it is easy to place the bit exactly where I want and the mass of the machine keeps anything from moving during the process.

while all 'technical' suggestions & insights make senses and sound appropriate, let me point out rather a sentimental & spiritual & religious. (aka perhaps useless).
drilling out a track fork—especially such vintage ones with tight clearance—always feels me a bit of blasphemy. i dunno.
i'd definitely try to fill the hole and naturally repaint—paint & rust looks bad already + brazing/welding will most likely hit the paint—like nothing happened, saving the soul of such gorgeous vintage pista fork. then a Keirin brake clamps—seller called Track Supermarket also carry a few kinds other than the ugly Dia Compe Spcaceship Alien Bionic Limb Simulators, IIRC.

Update
 

Just an update about how this turned out
https://cimg0.ibsrv.net/gimg/bikefor...b694e5393.jpeg
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Hi,
Curious about a few things....If you were not going to a brake were you worried about the loss of strength in that area? What did you use to fill in the spots did you weld/braze?
It looks like you used bondo on the rear brake bridge was that after the welding?
Personally I like the aesthetics of the original fork with the reliefs in the fork lug, if you agree is there any chance to get them back?
Best, Ben

No way in H**L I would have let those reliefs get changed. :eek:

Ow of course don’t worry I didn’t fill in the reliefs.

That photo is the rear side of the fork (photo taken from that side as that was actually the damaged hole/too low). On the front side I did file to keep the original shape of the fork in tact,

i did use metal filler rather than brazing in the end, down to not having access to my usual friends dads workshop. This was a diy job at my parents.

not worried structurally personally. And pretty happy as it’s totally unnoticeable now

Was a surprise to me.
Not mine.
The overall result was less than it was before to my eyes.
This crown is not my favorite, but is strong.
Now, it appears quite inexpensive and klunky.
A few minutes on a vertical mill can fix it up.
The brake solution is reasonable and resourceful.
The example of this crown I owned at one time had the trough on the front and back side.