GravelMN

I need to replace a fork that has a theaded steerer length of 146mm but the closest replacement I can find has a 200mm x 50mm threaded area steerer, the 175mm x 50mm version seems to be discontinued. Can a bike shop extend the threaded area so that the steerer can be cut to 146 and still have adequate threads for the headset? My alternative is to go with an unthreaded steerer and replace the headset and stem but that would add a lot to the cost of the project.

Thanks

FBinNY 

It's not a difficult job for a skilled mechanic to extend the threads. What is more difficult is extending the keyway, but many people opt to go without.

Just make sure that whoever you give this to knows what they're doing because while it's easy and straightforward, there are pitfalls and someone who doesn't know one of his body parts from another can easily destroy the fork.

BTW- if you can't find someone locally, you can send me the fork. PM me for pricing if it comes to that, but a local shop will be $15.00 less just based on round trip shipping.

Bezalel

When you bring it in, be sure to look for an older mechanic. Threading a fork isn't that intuitive just looking at the tool (improper use can cause damage) so experience counts.

Andrew R Stewart 

Simply running a steerer die further down the fork will often result in crappy threads being created. Been there, done that. Andy.

FBinNY 

Three things needed. The right die and handle, in good condition. The right cutting oil, which is as important as the right die. Skill and knowledge. The three elements together will produce threads as good or better than original 99.9% of the time.

Andrew R Stewart 

Francis- wish I could be 100% in agreement. I've used Var, Eldi, Campy, Park and other threading dies/tool holders many times. With many different lubes from various cutting fluids to simple oils. My experiences have been inconsistent at best.

Now I know that you (Bicycle Research) use to offer cutting tool classes BITD. I'd love to learn the subtleties. But I also know that most common steerer dies are at best chasers, not cutters. And that single pointing (which is beyond my skill set) is the best way to thread a steerer.

So I'm all ears to your methods. f you wish we can take this off list. Andy.

FBinNY 

To clear up a few misconceptions, the most important of which is that while I taught the subject over a number of years until the decline in road bikes and the related frame prep ended the market, I'm not affiliated with Bicycle Research, which was Don Milburger's company out in Concord Ca.

To my knowledge, all production fork threading is done with dies or releasing die heads, and nobody has single-pointed a steerer thread in production since something short of forever.

The dies sold in the bike trade, including those from Campy, Silva and Cobra are made of HSS and designed for cutting new thread. I believe that the Park dies should be also, but am not sure. Some of the other dies sold for the job were not HSS but could still cut new thread, but with shortened die life.

I suspect that the idea that the dies sold for the job were only suited for chasing originated from people who couldn't do the job successfully and, like the proverbial carpenter, blamed the tools.

Lastly, the role of cutting oil is critical to the success of the job since modern steerers are made of CroMo at a temper and grain structure that makes it more difficult tho thread than most materials. Also, since this material tends to make long, stringy chips which can easily load up and become a problem, skill in working with the material and process are important.

I'm thinking of offering my old course if there's enough demand now that I'm out of the distribution business and have the time, not to mention that the dough would also be nice.

Dan Burkhart 

I don't have anything close to your experience with this, but I have done quite a bit of fork threading, and found what works for me is lots of cutting fluid, and going slow. Very slow.
Cutting generates heat, and heat expands the thin wall tubing quite rapidly. If I'm threading a fork, I set it up when I'm working on some other job, and cut maybe two revolutions at a time, advancing 1/4 turns and backing off 1/2 to break and clear chips.
Then, I leave it and work on something else, returning to cut a couple more turns later.

Aladin

What flavor of bike.. MTB, road or ? I have a few hanging in the garage........

fietsbob

the tool handle for a bicycle fork threading die, is a special one .

.. there is another Sheldon trick use a 1" threadless headset and spacers and the top lock nut on the threads

better.. if you can get a 2nd through-threaded nut to use a Paired jam-nut scheme.



I did a threading extension, before the threadless headset was a thing.. if I were to do it again that combination scheme is what I'd Do..


Cannondale shipped a cable hanger that had a thin 32mm nut and a pinch bolt piece ,with the bikes.
shop assemblies often used regular headset parts

so a bin of these nuts filled up .. I found them very useful in my touring bike build ,, where I had a tall fork steerer for stem height.

GravelMN

What I'm looking for is a chrome-moly fork from an early 1990s Trek 720 or 730. My frame is 21" so the 1" threaded steerer needs to be at least 146mm (5.75") and a longer one would need to have threading so that it could be cut to that length. Color doesn't matter as I plan to have the bike powder coated once I get a new fork. I have a hi-ten fork from a 700 that would fit but would really prefer the chrome-moly version that came on the higher end bikes.

Aladin

Have an older Schwinn here.. believe those are chro/moly (?). 7" (near 2" thread) tube.. 14 3/16" from brake hole center to start of axle slot.
Glad to send it over if you want it.

GravelMN

Thanks for the offer, but I'll need something beefier with canti brake studs.

Aladin

Have that fork too.. but steer is under 5". Have very similar.. tube is well over 7".

GravelMN

Will PM you.