Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

BB cross threaded

Notices
Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

BB cross threaded

Old 11-11-19, 01:29 AM
  #1  
Ben clegg
Newbie
Thread Starter
 
Join Date: Jun 2018
Location: Dubai UAE
Posts: 2

Bikes: Gravel, MTB , aero

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
BB cross threaded

Hi
Does anyone have any tips on how to rethread the BB?
I've had the frame resprayed and the thread is now clogged with paint, i've managed to get the right side in but am struggling getting a straight start to the thread on the left (none drive side).
The frame is aluminum .
Any ideas out there?
Ben clegg is offline  
Old 11-11-19, 01:48 AM
  #2  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 26,884
Mentioned: 213 Post(s)
Tagged: 0 Thread(s)
Quoted: 15732 Post(s)
Liked 3,157 Times in 2,352 Posts
Paint or powdercoat?

Many older bike shops should have thread taps, and chasing the threads should be relatively easy if there is enough to catch the original threads.

You can also "face" the bottom bracket which will clean any paint off of the outside edges, and get yourself a nice square face to work with.
CliffordK is offline  
Old 11-11-19, 02:27 AM
  #3  
Unca_Sam
The dropped
 
Unca_Sam's Avatar
 
Join Date: Oct 2018
Location: Columbus, OH
Posts: 2,243

Bikes: Pake C'Mute Touring/Commuter Build, 1989 Kona Cinder Cone, 1995 Trek 5200, 1973 Raleigh Super Course FG, 1966 Schwinn Deluxe Racer, 1960/61 Montgomery Ward Hawthorne "thrift" 3 speed, by Hercules

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 1603 Post(s)
Liked 899 Times in 620 Posts
Clifford has the best choice. If you're strapped for cash, try a brass brush rotated along the threads to expose more of them, then chase with a well lubricated cup a few times.
Unca_Sam is offline  
Old 11-11-19, 09:43 AM
  #4  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 103 Times in 81 Posts
Paint stripper, carefully applied.
AnkleWork is offline  
Old 11-11-19, 09:52 AM
  #5  
ign1te
Senior Member
 
Join Date: Dec 2015
Posts: 78
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 25 Post(s)
Liked 11 Times in 7 Posts
Use a power drill + wire brush wheel of appropriate size inserted directly into BB shell. If your drill is even moderately powerful, the paint will come off.
ign1te is offline  
Old 11-11-19, 01:44 PM
  #6  
Crankycrank
Senior Member
 
Join Date: Jan 2009
Location: San Diego, CA
Posts: 2,965
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 621 Post(s)
Liked 566 Times in 433 Posts
Originally Posted by ign1te View Post
Use a power drill + wire brush wheel of appropriate size inserted directly into BB shell. If your drill is even moderately powerful, the paint will come off.
I would avoid any power tools on aluminum threads. It will destroy them pretty quickly.
Crankycrank is offline  
Old 11-11-19, 01:59 PM
  #7  
Reynolds 
Passista
 
Reynolds's Avatar
 
Join Date: Jul 2005
Posts: 7,363

Bikes: 1998 Pinarello Asolo, 1992 KHS Montaña pro, 1980 Raleigh DL-1, IGH Hybrid, IGH Utility

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 790 Post(s)
Liked 489 Times in 278 Posts
You can make thread cleaning taps with old steel cups and a Dremel.
Reynolds is offline  
Likes For Reynolds:
Old 11-11-19, 02:02 PM
  #8  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 26,884
Mentioned: 213 Post(s)
Tagged: 0 Thread(s)
Quoted: 15732 Post(s)
Liked 3,157 Times in 2,352 Posts
Originally Posted by Reynolds View Post
You can make thread cleaning taps with old steel cups and a Dremel.
Probably.

Although a real tap kit will hold the tap into alignment as long as it can catch the first thread.
CliffordK is offline  
Old 11-11-19, 02:25 PM
  #9  
Bill Kapaun
Really Old Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Posts: 13,048

Bikes: 87 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.

Mentioned: 17 Post(s)
Tagged: 0 Thread(s)
Quoted: 1476 Post(s)
Liked 735 Times in 540 Posts
Originally Posted by Reynolds View Post
You can make thread cleaning taps with old steel cups and a Dremel.
And use them as "plugs" before painting-
Bill Kapaun is offline  
Likes For Bill Kapaun:
Old 11-11-19, 03:27 PM
  #10  
Unca_Sam
The dropped
 
Unca_Sam's Avatar
 
Join Date: Oct 2018
Location: Columbus, OH
Posts: 2,243

Bikes: Pake C'Mute Touring/Commuter Build, 1989 Kona Cinder Cone, 1995 Trek 5200, 1973 Raleigh Super Course FG, 1966 Schwinn Deluxe Racer, 1960/61 Montgomery Ward Hawthorne "thrift" 3 speed, by Hercules

Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 1603 Post(s)
Liked 899 Times in 620 Posts
Originally Posted by Bill Kapaun View Post
And use them as "plugs" before painting-
Yeah, masking off important threads shouldn't be overlooked. An ounce of prevention...
Unca_Sam is offline  
Old 11-11-19, 03:36 PM
  #11  
dedhed
SE Wis
 
dedhed's Avatar
 
Join Date: Apr 2005
Location: Milwaukee, WI
Posts: 8,917

Bikes: '68 Raleigh Sprite, '02 Raleigh C500, '84 Raleigh Gran Prix, '91 Trek 400, 2013 Novara Randonee, 1990 Trek 970

Mentioned: 32 Post(s)
Tagged: 0 Thread(s)
Quoted: 2094 Post(s)
Liked 2,063 Times in 1,282 Posts
Are you first turning it in the wrong direction and feeling for it to "drop" and align? I realize with the fine threads of a BB feeling the drop isn't like coarse threads.
dedhed is offline  
Old 11-11-19, 05:07 PM
  #12  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 26,884
Mentioned: 213 Post(s)
Tagged: 0 Thread(s)
Quoted: 15732 Post(s)
Liked 3,157 Times in 2,352 Posts
Originally Posted by dedhed View Post
Are you first turning it in the wrong direction and feeling for it to "drop" and align? I realize with the fine threads of a BB feeling the drop isn't like coarse threads.
The other point, of course, is that:

For standard English/ISO threading, pedals are right/right, left/left

Bottom brackets are just the opposite.

Right hand side, left threads.
Left hand side, right threads.

So, if the OP has already gotten the right hand side in, then that shouldn't be an issue. But, it is always worth considering.
CliffordK is offline  
Old 11-11-19, 05:45 PM
  #13  
3alarmer 
Friendship is Magic
 
3alarmer's Avatar
 
Join Date: Nov 2010
Location: The Big Tomato
Posts: 20,542

Bikes: old ones

Mentioned: 292 Post(s)
Tagged: 0 Thread(s)
Quoted: 23296 Post(s)
Liked 6,711 Times in 4,802 Posts
.
...find someone with a set of piloted taps. Takes 5 minutes with the right tool, and the repair costs if you genuinely cross thread it the entire length of one side will far exceed whatever someone charges you to do it. We have a set of piloted taps at the bike co-op here, (both English and Italian). See if there's a similar bicycle co-op near you. If you already have one side working well, the pilot shaft will make short work of getting the other side started properly.

3alarmer is online now  
Old 11-11-19, 06:06 PM
  #14  
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Posts: 8,424

Bikes: 85 team Miyata (modern 5800 105) , '84 Team Miyata,(dura ace old school) 80?? SR Semi-Pro 600 Arabesque

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 1709 Post(s)
Liked 1,275 Times in 796 Posts
Originally Posted by CliffordK View Post
Paint or powdercoat?

Many older bike shops should have thread taps, and chasing the threads should be relatively easy if there is enough to catch the original threads.

You can also "face" the bottom bracket which will clean any paint off of the outside edges, and get yourself a nice square face to work with.
+1 for the win
squirtdad is offline  
Old 11-11-19, 07:32 PM
  #15  
Mad Honk 
Senior Member
 
Join Date: May 2019
Location: Bloomington, IN
Posts: 1,886

Bikes: Schwinn Paramounts, Patelli Professional, Othon Ochsner, Masi, Faggin

Mentioned: 56 Post(s)
Tagged: 0 Thread(s)
Quoted: 795 Post(s)
Liked 788 Times in 556 Posts
Triple alarmer,
Those taps aren't cheap! the last set I bought were $160, so any bike shop doing thread chasing is gonna want some compensation for the tools and the job.
But the best way to do a thread cleaning is with the piloted threading tools. I have a number of vintage bikes that were sent out for recovering with powder coatings and the best option was to use the piloted taps for cleaning the threads after the painting. My advice to anyone with this problem is to look to a professional for help. The cost are just too high for the home mechanic. Smiles, MH
Mad Honk is offline  
Old 11-11-19, 09:52 PM
  #16  
3alarmer 
Friendship is Magic
 
3alarmer's Avatar
 
Join Date: Nov 2010
Location: The Big Tomato
Posts: 20,542

Bikes: old ones

Mentioned: 292 Post(s)
Tagged: 0 Thread(s)
Quoted: 23296 Post(s)
Liked 6,711 Times in 4,802 Posts
.
...I bought some Cyclus ones through an online Dutch website about 8-10 years ago (for about 100 bucks a set, with the handles) when I got tired of always dragging my projects over to the co-op. In my case, they've more than paid for themselves, but I have a lot of projects.

I see they're up to 118 bucks American now. But unless you have some other stuff to order at the same time, the shipping costs are another 30 bucks. Nonetheless, they seem to be pretty solid tools based on my experience with them. I wish I could get a set of French threaded ones somewhere, instead of using my trusty single tapered tap in that size, one side very carefully at a time.
3alarmer is online now  
Old 11-11-19, 10:10 PM
  #17  
Gresp15C
Senior Member
 
Gresp15C's Avatar
 
Join Date: Sep 2014
Posts: 3,763
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1017 Post(s)
Liked 587 Times in 380 Posts
Sometimes, if just one or two threads are dinged up, you can use a hand tap of the same pitch but a smaller diameter, as a scraper to clean internal threads. An old machinist taught me that.
Gresp15C is offline  
Old 11-11-19, 10:21 PM
  #18  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 10,402

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 111 Post(s)
Tagged: 0 Thread(s)
Quoted: 3395 Post(s)
Liked 2,146 Times in 1,397 Posts
If these are English taps and they cannot be saved and you want to keep this frame there is always the Italian thread option. Italian BBs are enough bigger that any English, French or Swiss BB shell threads at any state of disrepair can be drilled and tapped to Italian and basically be like new. (But care for them. There is no place to go if you mess them up.) You will have to find the shop that has the taps and they will want real money to do this.

I've never had to do this but have known of this for the past 40 somethng years.

Ben
79pmooney is offline  
Likes For 79pmooney:
Old 11-12-19, 07:00 AM
  #19  
wheelreason
Senior Member
 
Join Date: Aug 2009
Posts: 733
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 110 Post(s)
Likes: 0
Liked 10 Times in 9 Posts
Originally Posted by Mad Honk View Post
...any bike shop doing thread chasing is gonna want some compensation for the tools and the job...
MH
Greedy LBS! I live for roadies coming in with stuff where they bit off too much, the algorithm says CHARGE!
And yes, it takes longer to take the tool out of the case, clean it, and put it away that the job itself, but hey, the only tool I like more than taps (grinder doesn't count) is my Abbey HAG.
wheelreason is offline  
Old 11-12-19, 09:29 AM
  #20  
Ronsonic 
Senior Member
 
Join Date: Dec 2005
Location: Sunny Tampa, Florida
Posts: 1,540
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 100 Post(s)
Liked 44 Times in 36 Posts
On a recent build my favorite shop gave the new-to-me frame a full inspection and did a needed "chase and face" on the BB shell for $35.

I cannot tell you how much better a build goes together with this sort of treatment. I used to just work with what I got and then after a couple of builds with properly serviced Headtubes and Bottom Brackets and aligned Drop-Outs, etc. I am not going to skip this stuff again.

I am cheap, would rather DIY whenever I can, but ...

Really, it's worth it.
Ronsonic is offline  
Old 11-12-19, 09:30 AM
  #21  
hokiefyd 
Senior Member
 
hokiefyd's Avatar
 
Join Date: Feb 2017
Location: Northern Shenandoah Valley
Posts: 3,833

Bikes: '18 Redline Zander, '14 Surly Pugsley, '97 GT Vantara, '97 Trek MultiTrack 750, '70 Peugeot UO-18 Mixte

Mentioned: 33 Post(s)
Tagged: 0 Thread(s)
Quoted: 1319 Post(s)
Liked 584 Times in 443 Posts
Originally Posted by Reynolds View Post
You can make thread cleaning taps with old steel cups and a Dremel.
I have done this, and it's worked great on a few occasions. This video should help you (or anyone) out, if all you truly have to do is clean paint or other garbage out of otherwise good threads:

hokiefyd is offline  
Likes For hokiefyd:
Old 11-12-19, 12:14 PM
  #22  
AnkleWork
Senior Member
 
Join Date: Jan 2013
Location: Llano Estacado
Posts: 3,702

Bikes: old clunker

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 684 Post(s)
Likes: 0
Liked 103 Times in 81 Posts
OP: Is it cross-threaded or just clogged with paint?
Some in this forum default to the most destructive methods first and forget that taps only remove metal, not "restore" it. Using a tap should follow after some other (nondestructive) methods have been tried, and only when proven necessary. Also as mentioned above, even brass wire brushing will damage aluminum threads if not done gently. Excessive brushing work-hardens and distorts the surface making subsequent remediation much more difficult.

Last edited by AnkleWork; 11-12-19 at 01:57 PM.
AnkleWork is offline  
Old 11-19-19, 01:27 AM
  #23  
Ben clegg
Newbie
Thread Starter
 
Join Date: Jun 2018
Location: Dubai UAE
Posts: 2

Bikes: Gravel, MTB , aero

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Hi People
Thanks for all the advice , I didn't want to take it to the shop nor buy a special tool that I would only use once in a blue moon, as I wanted to see if I could do this myself. So this is what I eventually ended up doing.

Faced the edge with a packing knife blade, this made it easier for me to see what I was up against.
I then used the packing knife in the grooves of the thread, I was surprised how easy this was to get out a lot of the paint.
Eventually I used the "RJ guys" method (thanks hokiefyd) of using an old square type bottom bracket to re-cut the rest of the threads . Did this on both sides and now I can screw the new bottom bracket all the way in and out with my fingers.

Thanks to everyone for all the suggestions, really appreciated
Ben clegg is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.