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  1. #1
    In beaurocratic limbo urbanknight's Avatar
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    How hard to extend threads on fork?

    I think I finally found a fork with the correct specs for my bike, but it came off a 61cm bike while mine is a 55cm so the steerer is about 7cm too long. I know a shop nearby that can extend the thread for me, but is it asking too much to have them thread that far down?
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

  2. #2
    black betty DeadSailor's Avatar
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    hmmmmmmmm is this for the compression bolt?

    why dont you just star nut that motha

    if the thread is on the out side of the steer tube for those type of head sets. and you mean shop as i bike shop....id try to find a machine shop instead. they do that stuff all the time so itll be less

  3. #3
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    Extending the threading can be done if the shop has the correct dies, in good condition and knows how to use them. Also, the steerer must NOT be chromed although this is a very unlikely problem.

    7 cm is quite a way but it can be done.

  4. #4
    In beaurocratic limbo urbanknight's Avatar
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    Deadsailor, you mean just cutting it down and using it as a threadless setup? The only problem with that is I would need to buy a new headset and stem to do that. Aside from that, it would work right?

    The shop I have in mind has done it for me before with no problems, but those threads only needed to be extended 1 cm, not 7. The steerer is not chromed, but considering the length, I don't want to find out that it takes the poor guy an hour to do it.
    Last edited by urbanknight; 06-25-07 at 06:37 PM.
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

  5. #5
    cab horn
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    I'm just going to emphasize the "if they know how to use it properly" part with the LBS. Make sure they have a proven track record.

    I'm going to go with the cut it down and threadless it part. A new headset is like $10-$20. Stem, same price or less. Or you can gamble with the thread extension. I know of a handful of bike shops that can do this competently and I live in a large city with billions of bike shops.
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  6. #6
    hello roadfix's Avatar
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    B & H on Mission St in So Pas extended the threading on my Cinelli fork for $10 about 4 years ago. Steerer tube was also chromed. They weren't reluctant in taking the job. I knew about this shop but before I went to them I must have gone to two or three different nearby shops. None wanted to touch my fork.

  7. #7
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    Quote Originally Posted by roadfix
    Steerer tube was also chromed. They weren't reluctant in taking the job.
    My mention of the chrome was based on at least one tool maker's (Park?) explicit warning not to thread over chrome plating. I guess it worked anyway.

  8. #8
    In beaurocratic limbo urbanknight's Avatar
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    The chrome plating warning is probably because of how hard it makes the metal. More dangerous for the die than the fork I assume. Thanks for the local suggestion, roadfix, but Reseda Bicycles is right down the street and did the cutting and rethreading on my "this-will-do-for-now" fork for $10 as well. They have been around for longer than I have been riding, they love old school roadie stuff, and they don't flinch at these kinds of jobs.
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

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    Quote Originally Posted by urbanknight
    The chrome plating warning is probably because of how hard it makes the metal. More dangerous for the die than the fork I assume.
    Exactly. The warning came from a tool maker, not a fork maker.

  10. #10
    I pedal what I ride
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    if you are going to get the steerer cut down by 7 cm check if it is butted. Taking that much off will mean the stem will go that much further into the steerer tube and most probably hit the part where the steerer narrows. you may need a stem with a shorter quill section.

  11. #11
    Your mom
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    +1 on going threadless.

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    In beaurocratic limbo urbanknight's Avatar
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    Thanks mentat6059, I hadn't thought of that.

    Is the threaded-to-theadless operation a sure success? I mean, there won't be any issues getting the star nut in and getting the stem to clamp safely?
    "Well, I guess you can cut the arts as much as you want... Sooner or later, these kids aren't going to have anything to read or write about." (Richard Dreyfus as Glenn Holland)

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    Quote Originally Posted by urbanknight
    Is the threaded-to-theadless operation a sure success? I mean, there won't be any issues getting the star nut in and getting the stem to clamp safely?
    It is important that you cut off enough of the steerer tube to eliminate almost all (all would be better) of the threads so the new stem clamps on smooth tubing. The threads are weak points and stress raisers and the stem should not be clamped over them.

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    * vpiuva's Avatar
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    Before you cut make sure that you have enough steerer - head tube + new headset stack height + new stem + spacers. Measure twice and then recheck your calculations

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    Senior Member miamijim's Avatar
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    Chrome can be removed with a belt sander. I've removed plenty of chrome from forks in the past. It takes all of an extra 3 minutes to thread a fork 7cm versus 1 cm.

    How much did they quote you?
    WWW.CYCLESPEUGEOT.COM 2005 Pinarello Dogma; 1991 Paramount PDG 70 Mtb; 1976? AD Vent Noir; 1989 LeMond Maillot Juane F&F; 1993? Basso GAP F&F; 1989 Terry Symmetry; 2003 Trek 4700 Mtb; 1983 Vitus 979

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    Quote Originally Posted by urbanknight
    Deadsailor, you mean just cutting it down and using it as a threadless setup? The only problem with that is I would need to buy a new headset and stem to do that. Aside from that, it would work right?

    The shop I have in mind has done it for me before with no problems, but those threads only needed to be extended 1 cm, not 7. The steerer is not chromed, but considering the length, I don't want to find out that it takes the poor guy an hour to do it.
    How can you use a threaded fork with a threadless setup? The fork steerer is not long enough almonst other issues. OP - How much is TOO much for the LBS to do this job? Love these posts where the part/labor whatever is too expensive with no refrence to the cost.

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    Quote Originally Posted by oilman_15106
    How can you use a threaded fork with a threadless setup? The fork steerer is not long enough almonst other issues.
    In this case the steerer might be long enough to remove all the threaded portion and still be long enough to work with a threadless stem/headset.

  18. #18
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    caution - some forks are butted to save weight. Cutting threads into the thinner butted portion of the steerer tube will cause serious problems down the road. Usually you can do a cm or two but that's about it.

    cdr

  19. #19
    In beaurocratic limbo urbanknight's Avatar
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    Oilman, I'm lucky enough that the fork is off a 61cm bike frame while mine is a 55cm, so I have over 2 1/1 inches of extra steerer tube. The threading on this one is about 1 inch, so that SHOULD leave me enough room. As for the cost, that's not really the issue since if I can't find a fork with these odd dimensions I'll need a new frame instead. Sorry if I was confusing, but I meant "too much work" as in not wanting to wear out my welcome with the shop. They know me and charge fair rates, and also feel bad about the run of bad luck I've had, but I don't want to walk in with a job that makes them grumble after I walk out the door.

    Carpediemracing, aside from feeling around the inside, how might I know if it's butted? It's a stock fork off a mid grade Bianchi Campione, so it's probably a fork that has straight tubes so they could just take it off the shelf and cut it for the bike on the aseembly line. If it is butted, will the threadless option work or will the stemsquish the tube?

    For anyone who's interested, this is what I bought. I am leaning towards keeping it threaded, but will decide when I see it in person and measure it carefully myself. Thanks for all the help.

    http://cgi.ebay.com/ws/eBayISAPI.dll...140871687&rd=1

    The only risk is the rake might be 5mm short, but it's worth a shot because my next move is buying a whole new frame... one with a longer top tube and standard fork so I don't have to play this game again to get it fitted correctly

  20. #20
    vjp
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    Quote Originally Posted by carpediemracing
    caution - some forks are butted to save weight. Cutting threads into the thinner butted portion of the steerer tube will cause serious problems down the road. Usually you can do a cm or two but that's about it.

    cdr
    A steerer is butted at the bottom for strength, I have never heard of a steerer being butted at the top and bottom.

    vjp

  21. #21
    Sometimes knows stuff. rmfnla's Avatar
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    Quote Originally Posted by vjp
    A steerer is butted at the bottom for strength, I have never heard of a steerer being butted at the top and bottom.

    vjp
    +1

    Butting at the top could cause problems with a quill stem.

    FWIW extending threading is not a big deal assuming the shop has the threading tool. Beware if a "professional" balks at this type of work; he/she is a parts replacement nosepicker (remember that?), not a skilled wrench.
    Today, I believe my jurisdiction ends here...

  22. #22
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    My bad, I was trying to remember why threads shouldn't be cut on a fork. It isn't butting but it does have to do with minimum wall thicknesses.

    It's that the threads can be rolled onto a steerer instead of being cut into it. This means the material is sort of squished into shape versus carved out (same like forging versus machining).

    The way to tell if you have rolled threads is to see if the threads increase the diameter of the steerer. If you look down the steerer, the threaded part will seem wider in diameter with rolled threads. This is because the rolling processes squishes some of the metal up (the metal moved from the valleys have to go somewhere).

    If the threads aren't raised above the plain tube height the threads are cut into the steerer.

    The problem with rolled threads is usually the steerer wall thickness is minimal - it's designed to be strong enough for rolled threads, not for cut threads. If you cut threads, there is minimal material left at the bottom of the thread "valleys". It's almost like you're perforating the fork. In extreme cases you can see gaps in the metal where there is no material left at the bottom of the threaded valley.

    Sorry for misinformation. Hopefully this clarifies it.

    cdr

  23. #23
    In beaurocratic limbo urbanknight's Avatar
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    Thanks for the clarifications. What I gather here tells me it should be no problem to have them cut threads into this particular fork. My old Bianchi one was cut, not rolled, and I'll check this new one when it arrives to be sure.

    I'll be happy to get my top tube level again, but man what a PIA it has been!

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