stripped threads in Deore XT thumbshifters- Mtbr.com
Results 1 to 16 of 16
  1. #1
    bullmoose
    Reputation:
    Join Date
    Aug 2007
    Posts
    19

    stripped threads in Deore XT thumbshifters

    I have a technical question: I want to drill out the stripped threads in my plastic (ca. 1989) Deore XT thumbshifters (see photo) and use a longer bolt and a nut to secure the shifter to the handlebar. There seems to be enough material there to make this work. Has anyone tried this? Might you have suggestions?

    Thanks.

  2. #2
    mtbr member
    Reputation: deluxe's Avatar
    Join Date
    Aug 2004
    Posts
    174

    Retapping Thumbies

    Problem is that a bigger diameter bolt usually has a bigger head that won't fit into the recessed space for the bolt head.

    What I have done in the past, is alcohol the threads clean, then fill them somewhat with metalized epoxy, then re-drilled and tapped ""the original"" thread size. Then you can use the original bolt.
    Get the kind that says you can drill and tap it on the instructions, some aren't tough enough. Even so, you'll have to exercise care when tightening that bolt in the future.
    Wanted: Phil Wood front hub, one orphan WTB shifter mount.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Oct 2005
    Posts
    2,721
    is a bunch of things you can do besides drill the whole way ..

    for example You can always try to drill a little farder into the casting, being careful not to damage the already wasted threads, then tap the bore with the 6mm bit and use a longer bolt,

    A 1 to 1 ratio of the diameter/deep is accepted (1.5 of the diameter is optimal for load bearing structures), so 6mm bolt with 6mm of useful threads will be sufficient, even less if is just to clamp down.

    Using a 1/4 fine thread bolt with a Phillips head (so you don't need to carry a SAE allen around) is also really simple ..

    Or If you want to go even more sophisticated you can use a "Time sert" or a helicoil or a specific epoxi resin to rebuild the damage hole, a company call "Delcon" is the Cats Piyammas on this segment.

    in short don't lose your sleep over is no big deal at all.
    Last edited by patineto; 07-11-2008 at 06:44 PM.

  4. #4
    mtbr member
    Reputation: chefmiguel's Avatar
    Join Date
    Dec 2007
    Posts
    1,512
    In a pinch I had to drill through my xt shifter. I had to break out the dremel tool to shave some material too accomodate the new nut and bolt. A dozen years later its still works and holds on to my handlebars.

  5. #5
    Fat City Michael
    Reputation: Fatmikeynyc's Avatar
    Join Date
    Jun 2005
    Posts
    605

    stripped threads in Deore XT thumbshifters

    Quote Originally Posted by chefmiguel
    In a pinch I had to drill through my xt shifter. I had to break out the dremel tool to shave some material too accomodate the new nut and bolt. A dozen years later its still works and holds on to my handlebars.
    I've done the same thing as chefmiguel and I used whatever nut and bolt fit in the hole at the time and it worked fine and that also happened back in like 1996 on a Wicked Fat Chance...I think that shifter is currently on my Ti Fat Chance with the crappy bolt/nut combo and still works to this day...Just don't tighten it too much as it'll eventually crack since it's not really meant to drill out from the top.
    FATMIKEYNYC

  6. #6
    Schipperkes are cool.
    Reputation: banks's Avatar
    Join Date
    Feb 2004
    Posts
    4,156
    Heil-Coil.
    Quote Originally Posted by mikesee
    Better suited to non-aggressive 125# gals named Russell.
    I ride so slow, your Garmin will shut off.

  7. #7
    bonked
    Reputation: IF52's Avatar
    Join Date
    Jan 2004
    Posts
    2,129
    Quote Originally Posted by banks
    Heil-Coil.
    Yup, or Time-sert.

    Actually if you haven't completely mangled the hole with a drill yet, you can actually use a bolt that is about a milimeter longer than stock. The stock bolt is kind of short, combined with the weak threads in the base material, so you wind up only catching a few threads to begin with. The slightly longer bolt will grab the remaining threads. And from now on always tighten these shifters just to the point where they don't move easily on the bar.
    Quote Originally Posted by banks
    That is one big f'n dude!
    Yes I am!

  8. #8

    Reputation:
    Join Date
    May 2008
    Posts
    114
    Do not do that. It will not work. Besides, the mount is aluminum. You are better off drilling and tapping for a larger bolt, or to add a coil tap so you can use the original bolt size. There is no room for a nut if you drill all the way through. It will interfere with the shifter. You might want to try a little longer bolt since there are extra threads in the mount.

  9. #9
    Carsten
    Guest
    before you drill try the same type bolt but a little longer one. often the threaded part goes deeper than the lenght of the original bolt and then a few threads might be left that are undamaged. has worked a few times for me.

    that's not plastic btw, it's aluminum...
    Carsten

  10. #10
    bullmoose
    Reputation:
    Join Date
    Aug 2007
    Posts
    19
    Great suggestions, all. Thanks.
    I like the longer bolt idea as a first simple attempt at solving this. I'll try to rustle up something that fits the bill. I'm familiar with helicoils and such, but that seems a bit overkill since this is not a high stress part, and it is plastic after all. Elegant certainly, but I don't really see myself tracking down such a tiny helicoil (or is there an obvious place one would look for such a part).
    I'll let you know how it turns out.

    Thanks again.

  11. #11
    bullmoose
    Reputation:
    Join Date
    Aug 2007
    Posts
    19
    Oh. My mistake on the material. I'm glad it is aluminum. Makes more sense now that I think about it.

  12. #12
    Illuminati
    Reputation: scant's Avatar
    Join Date
    Jan 2004
    Posts
    1,727
    sometimes its just the obvious things in life I just tried the longer bolt suggestion & it worked for me, thanks guys

  13. #13
    mtbr member
    Reputation:
    Join Date
    Aug 2006
    Posts
    119
    I'd go with Carsten's simple solution on this one - every set of Xt thumbies that I've ever threaded I've just taken the bolt out and replaced with one thats a few mm longer. I'm using a set of those on my Bradbury Manitou right now with no worries. Don't know why but they used really short bolts on those shifters but threaded much deeper and as long as you were using original shimano bolts when you threaded them you'll still have loads of good threads in there.

  14. #14
    bullmoose
    Reputation:
    Join Date
    Aug 2007
    Posts
    19
    Well I tried the longer bolt, but it didn't take. Then I rummaged around in my bolt bins for something that might work. After some fiddling and a bit of drilling I got it. Not the most elegant solution, I admit, but very effective, and no trouble with clearance for the shifter movement.


  15. #15
    Fat City Michael
    Reputation: Fatmikeynyc's Avatar
    Join Date
    Jun 2005
    Posts
    605

    stripped threads in Deore XT thumbshifters

    That's pretty much what mine looks like except I was lucky enough to find a flat-head screw the was recessed into the hole up top, making it less noticeable. Good Job!
    FATMIKEYNYC

  16. #16
    mtbr member
    Reputation:
    Join Date
    May 2020
    Posts
    1

    Stripped 7 speed Shimano Deore XT shifter housing - fixed it!

    I recently had a stripped 7 speed XT thumb-shifter, instead of drilling through it, I tapped it to the next size bolt, super simple. Here is a pic of the tools I used, basically an inexpensive tap set, 10 minutes, done!
    Attached Thumbnails Attached Thumbnails stripped threads in Deore XT thumbshifters-ebff2472-b58b-4963-92e2-8a076f196a7e.jpg  

    stripped threads in Deore XT thumbshifters-19f8e3fe-abb0-4e94-b5d0-d9d87d2c57a7.jpg  


Members who have read this thread: 14

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.