Serotta Concours - Threading steerer on 1" new fork

[Flinch]

Title says it all. The present F1 fork will maybe squeeze in a 25mm tire, depending on how it inflates versus advertised size. I wanted a 28mm, so found a Kinesis Carbon 2 fork at our local bike coop. However, it was unthreaded, and since I have a King headset, was not gong to convert to threadless. I casually asked the manager if she knew of anyone in town who would thread the fork, and to my surprise she showed me the Park Tool threading set the coop owned. Cost to thread? $3 'rental' per hour - they have workspaces with tools, and you can work on bikes for cheap. Yes, the Park Tool is designed to both chase old, and cut new threads, contrary to what you may read on posts about threading forks. Says so in their instructions.

Well heck yes! I own a tap and die set, and have used it a lot, so was not afraid to tackle this. Before starting, I made sure that 1. The tube thickness was the same as for a threaded fork, ie: a 22.2 quill stem fits peachy. Miced the wall thickness, and same as F1 fork, 2. It was steel (no threading aluminum!), 3. Measured fifty times and cut once.

All told it was relatively easy, but ya gotta know how to use a threading die. Plenty of lube, file a small taper to the tube crown, make double damn sure the die starts 90 degrees from the crown, thread a quarter turn and back off a half to clear the swarf, take breaks to let the tube cool (or else if expands and the die cuts deeper), and periodically rotate the die back 2-3 turns to recut and clear the threads.

Fork installed, 28mm mounted, and rides sweet! Oh, and the coop has a professional steel fork alignment and bending setup - I'll use that next on my CSI. I'm pig, happy-happy -joy-joy wallowing in bike poo!

[monkeybanana86]

Nice...

[robt57]

Nice...

[oldpotatoe]

Well done and I think you were fortunate. Getting the thread 'parallel' to the fork crown race seat 'can' be a chore when starting with an unthreaded steerer. I had my Merckx MXLeader fork threaded but by a gent that had a lathe..so the threads were indeed parallel.

[thew]

Oh wow, sounds like a dreamy bike coop.

[Mike V]

Nice vice.

[grateful]

Flinch,

I am a ham fisted mechanic and I have a fork that I need to extend the existing threads by about 2cm or so. Any chance I could mail you the fork and have you add the threads? Happy to compensate you for your efforts.

[zennmotion]

Originally Posted by grateful

Flinch,

I am a ham fisted mechanic and I have a fork that I need to extend the existing threads by about 2cm or so. Any chance I could mail you the fork and have you add the threads? Happy to compensate you for your efforts.

Extending existing threads is a much easier deal than starting from a non-threaded steer tube, a local shop should be able to do that for you if they have the tool. I've threaded a steer tube from the beginning but it was definitely dicey going with 2 bad starts where I cut off a half inch or so from the end and started again before 3rd time dumb luck got the cut parallel. I wouldn't do it again with a fork I cared much about.

[tellyho]

My experience is that nobody has the tool anymore. Only the crustiest of shops.

[grateful]

This

Originally Posted by tellyho

My experience is that nobody has the tool anymore. Only the crustiest of shops.

[monkeybanana86]

Originally Posted by grateful

This

I had a fork with messed up threads and Box Dog Bikes in San Francisco fixed it with a tool that looks just like that. Would this tool be used for both cutting or chasing threads? Asking in case Grateful can't find anyone else.

[oldpotatoe]

Originally Posted by monkeybanana86

I had a fork with messed up threads and Box Dog Bikes in San Francisco fixed it with a tool that looks just like that. Would this tool be used for both cutting or chasing threads? Asking in case Grateful can't find anyone else.

Depends. Some tools are for 'chasing' and some are for 'chasing and cutting'.
The Campagnolo tool(which I have) is really a chasing tool, The Park tool is for cutting threads. Gotta be careful. If a 'chasing' tool is used a lot to cut threads, it may get dull/chipped and can kill the good threads of a fork.

[monkeybanana86]

Originally Posted by oldpotatoe

Depends. Some tools are for 'chasing' and some are for 'chasing and cutting'.
The Campagnolo tool(which I have) is really a chasing tool, The Park tool is for cutting threads. Gotta be careful. If a 'chasing' tool is used a lot to cut threads, it may get dull/chipped and can kill the good threads of a fork.

Cool, good to know.

I wish we had a like function on this forum.

[unterhausen]

There is no doubt my shop is really crusty and I have the die to thread a steerer with. I have threaded about an inch of steerer to extend the threads, and I would have to have a very good reason to do it again

[FriarQuade]

I really don't know where this whole clearing the threads nonsense started but it's really not necessary and only shortens the life of the cutter. You'll find that if you go several turns the swarf from the cut will curl up and evacuate out the back of the cutter pretty reliably. That said, there is a time and a place for peck taping but it's limited to really long threads, like 5 times the diameter of the thread or greater. A threaded steer or a bottom bracket is nowhere close to needing a clearing move.

fwiw, I was taught this bad habit as well when I started working in shops as a kid. But since then I've learned plenty of proper metal working and this is one thing that's always stood out as a counter productive method.