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Correcting a cross-threaded bottom bracket?



 
 
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  #11  
Old October 13th 15, 11:57 PM posted to rec.bicycles.tech
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Default Correcting a cross-threaded bottom bracket?

On Monday, October 12, 2015 at 5:27:58 AM UTC-7, AMuzi wrote:
On 10/12/2015 4:06 AM, Sir Ridesalot wrote:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


A piloted tap set can remove occlusions and ensure both
threads are on the same axis.

Taps however are subtractive machining. You won't have any
more thread height than now, and likely less. Some
inspection, measurement, analysis and advice from someone
who does this work regularly would be a good start.

--
Andrew Muzi


You are absolutely correct but should add that steel bottom brackets in older bikes have MORE than enough thread length and depth to be strong enough unless the threads were almost completely stripped out by repeatedly cross threading..
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  #12  
Old October 14th 15, 12:04 AM posted to rec.bicycles.tech
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Default Correcting a cross-threaded bottom bracket?

On Monday, October 12, 2015 at 7:00:11 AM UTC-7, Sir Ridesalot wrote:
On Monday, October 12, 2015 at 9:44:49 AM UTC-4, John B. wrote:
On Mon, 12 Oct 2015 02:06:12 -0700 (PDT), Sir Ridesalot
wrote:

I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


Depending on how badly the threads are deformed it may be possible to
recut the threads sufficiently to install a new bottom bracket
bearing.

If that fails there are "threadless bottom brackets" that can be used
to repair it. Velo Orange, and probably others, sell them, see
http://store.velo-orange.com/index.p...-brackets.html
--
cheers,

John B.


I'm taking the frame to a shop tomorrow(closed today due to it being Thanksgiving Monday here in Canada) and see what they charge to chase the threads. The threadless bottom braket might be the easiest way to go though. It's a very nice frame ideally suited for conversion to a drop bar touring bike for fire/logging/mining roads touring.

Cheers


I do not believe that they offer a system that would be compatible with yours. Unless you're willing to update to the newer style cranks with feed-through type connections. And since these are 10 speed the six or seven speed chains aren't compatible. etc. Andrew's suggestion of cleaning the threads was the best way. This will almost never give you any problems.
  #13  
Old October 14th 15, 12:09 AM posted to rec.bicycles.tech
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Default Correcting a cross-threaded bottom bracket?

On Tuesday, October 13, 2015 at 2:16:16 PM UTC-7, Sir Ridesalot wrote:
On Monday, October 12, 2015 at 5:06:19 AM UTC-4, Sir Ridesalot wrote:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


I used an old pair of bottom bracket cups to make a tool to cleanup the threads. I cut some grooves into a fixed cup and made a spacer to fit inside the fixed cup and adjustable cup. I screwed the adjustable cup inmost of the way and then started the fixed cup supported by the internal spacer as I threaded the fixed cup in I backed out the adjustable cup which with the spacer kept the fixed cup square to the bottom bracket shell. Surprisingly, by working very slowly on it, it worked and I was able to cleanup the cross threading and then install a sealed cartridge bottom bracket. Everything tightened up okay. i guess my next step will be to strip the frame and repaint it. i also need to either get a riser quill stem, a quill to threadless stem adapter and stem, or an adjustable stem to get the bars uo to where I most prefer them. A shakedown ride today shows that all's well except I'd prefer a bit longer reach on my stem.

Cheers


Old BB cups are not made with metal hard enough to clean threads properly. That's why taps are made of extremely hardened steel. To the point where they can be broken if mishandled.
  #14  
Old October 14th 15, 12:19 AM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 5,270
Default Correcting a cross-threaded bottom bracket?

On Tuesday, October 13, 2015 at 7:09:22 PM UTC-4, wrote:
On Tuesday, October 13, 2015 at 2:16:16 PM UTC-7, Sir Ridesalot wrote:
On Monday, October 12, 2015 at 5:06:19 AM UTC-4, Sir Ridesalot wrote:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


I used an old pair of bottom bracket cups to make a tool to cleanup the threads. I cut some grooves into a fixed cup and made a spacer to fit inside the fixed cup and adjustable cup. I screwed the adjustable cup inmost of the way and then started the fixed cup supported by the internal spacer as I threaded the fixed cup in I backed out the adjustable cup which with the spacer kept the fixed cup square to the bottom bracket shell. Surprisingly, by working very slowly on it, it worked and I was able to cleanup the cross threading and then install a sealed cartridge bottom bracket. Everything tightened up okay. i guess my next step will be to strip the frame and repaint it. i also need to either get a riser quill stem, a quill to threadless stem adapter and stem, or an adjustable stem to get the bars uo to where I most prefer them. A shakedown ride today shows that all's well except I'd prefer a bit longer reach on my stem.

Cheers


Old BB cups are not made with metal hard enough to clean threads properly.. That's why taps are made of extremely hardened steel. To the point where they can be broken if mishandled.


Maybe not but that tol I made worked well. if there were no threads and i was cutting threads then i know i'd need a special tool. Bike shops with the proper tools and people who know how to use them are not that close to where i live. i have to either bicycle to tthe shop or take an inter-city bus.

As far as the cartridge bottom bracket goes, I have a number of NOS ones here suitable for triples and i have some for doubles and singles too. There's a shop 25km (15 miles) from me that has lots of NOS square taper bottom brackets including Italian threaded ones at very low prices i.e. $5.00 to $10.00 on average. that's only a 50 km round trip ride but I need to find out what days he's open.

One thing I really like about tthe old school cranks like the Deore and sugino that I've collected as replacementsa is that I can get a very low Q-factor with them.

Cheers
  #15  
Old September 23rd 17, 07:09 PM posted to rec.bicycles.tech
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Default Correcting a cross-threaded bottom bracket?

segunda-feira, 12 de Outubro de 2015 Ã*s 10:06:19 UTC+1, Sir Ridesalot escreveu:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


Worth a try....desperate times - desperate measures. Cut 3 grooves in an old shell with a cutting disk as has been suggested and weld on a bar for leverage. Another "**** or bust" technique, not for the faint hearted...if you can get the cup in a few threads and can see it is skew by one thread (as often happens)give the part of the cup which protrudes more a SHARP TAP (a judicious blow)with a hammer! Then continue with the cup wrench and see if it goes in. THEN SELL THE KLUNKER POST HASTE! Or keep it (as in my case) ;-)
  #16  
Old September 23rd 17, 07:45 PM posted to rec.bicycles.tech
AMuzi
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Default Correcting a cross-threaded bottom bracket?

On 9/23/2017 1:09 PM, wrote:
segunda-feira, 12 de Outubro de 2015 Ã s 10:06:19 UTC+1, Sir Ridesalot escreveu:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


Worth a try....desperate times - desperate measures. Cut 3 grooves in an old shell with a cutting disk as has been suggested and weld on a bar for leverage. Another "**** or bust" technique, not for the faint hearted...if you can get the cup in a few threads and can see it is skew by one thread (as often happens)give the part of the cup which protrudes more a SHARP TAP (a judicious blow)with a hammer! Then continue with the cup wrench and see if it goes in. THEN SELL THE KLUNKER POST HASTE! Or keep it (as in my case) ;-)


A more circumspect technique would be to clean the BB shell
well, inspect for visible thread damage in good light with a
magnifier. If damage is found, correct that (tap to larger
size or fill and thread).

If not visibly damaged, run your go-nogo thread gauges on
the cleaned threads to evaluate before jamming something in
them.

Note that taps are subtractive only. Missing material cannot
be completely corrected by cutting, although smashed threads
may have sufficient height once cleared.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #17  
Old September 23rd 17, 11:02 PM posted to rec.bicycles.tech
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Default Correcting a cross-threaded bottom bracket?

On Saturday, September 23, 2017 at 11:46:01 AM UTC-7, AMuzi wrote:
On 9/23/2017 1:09 PM, wrote:
segunda-feira, 12 de Outubro de 2015 Ã s 10:06:19 UTC+1, Sir Ridesalot escreveu:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


Worth a try....desperate times - desperate measures. Cut 3 grooves in an old shell with a cutting disk as has been suggested and weld on a bar for leverage. Another "**** or bust" technique, not for the faint hearted...if you can get the cup in a few threads and can see it is skew by one thread (as often happens)give the part of the cup which protrudes more a SHARP TAP (a judicious blow)with a hammer! Then continue with the cup wrench and see if it goes in. THEN SELL THE KLUNKER POST HASTE! Or keep it (as in my case) ;-)


A more circumspect technique would be to clean the BB shell
well, inspect for visible thread damage in good light with a
magnifier. If damage is found, correct that (tap to larger
size or fill and thread).

If not visibly damaged, run your go-nogo thread gauges on
the cleaned threads to evaluate before jamming something in
them.

Note that taps are subtractive only. Missing material cannot
be completely corrected by cutting, although smashed threads
may have sufficient height once cleared.


It should also be stated that it is rare that ANYONE could install a bottom cross threaded enough that simply chasing the threads wouldn't restore full use. Though as someone that has apparently done it, it is possible.
  #18  
Old September 24th 17, 12:53 AM posted to rec.bicycles.tech
Sir Ridesalot
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Default Correcting a cross-threaded bottom bracket?

On Saturday, September 23, 2017 at 6:02:16 PM UTC-4, wrote:
Snipped
It should also be stated that it is rare that ANYONE could install a bottom cross threaded enough that simply chasing the threads wouldn't restore full use. Though as someone that has apparently done it, it is possible.


I know a guy who managed to screw a RIGHT-hand pedal onto a LEFT crankarm. I asked him did he not notice that it was REALLY HARD to screw that pedal on. He said he did notice that.

Cheers
  #19  
Old September 24th 17, 01:13 AM posted to rec.bicycles.tech
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Posts: 6,374
Default Correcting a cross-threaded bottom bracket?

SAAR ? or equivalent bike tool many ...

has a BB tap for you. I'm on immobile device n cannah see what but look at 'Bike tools ect'

Go to a machine shop.

Review Locktite products...beyond Red there is a loose plain bearing liquid.

If the new BB case is prob vinyl or plastIC I'm a sure there's a shock proof vi yl cement or epoxy to beef in the thread clearance to 0

That's a new area for me so ? I used red on butchered Stihl chain saw casing threadS 30 years ago worked ok. The case was prob vinyl kinda cardboard compared to today
  #20  
Old September 24th 17, 03:52 AM posted to rec.bicycles.tech
John B.[_3_]
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Default Correcting a cross-threaded bottom bracket?

On Sat, 23 Sep 2017 11:09:29 -0700 (PDT), wrote:

segunda-feira, 12 de Outubro de 2015 às 10:06:19 UTC+1, Sir Ridesalot escreveu:
I was finally able to get the bottom bracket off of a friend's steel frame English threads bottom bracket bike. Whew what a job! The fixed cup cup was cross-threaded. He wants to put in a standard square-taper spindle cartridge bottom bracket. The problem is since the fixed cup was cross-threaded I can't get the new cartridge to thread in properly. Does a decent bicycle shop have a way to correct the cross-threaded threads in the bottom bracket shell? If so what's a ballpark price for doing it?

Thanks and cheers


Worth a try....desperate times - desperate measures. Cut 3 grooves in an old shell with a cutting disk as has been suggested and weld on a bar for leverage. Another "**** or bust" technique, not for the faint hearted...if you can get the cup in a few threads and can see it is skew by one thread (as often happens)give the part of the cup which protrudes more a SHARP TAP (a judicious blow)with a hammer! Then continue with the cup wrench and see if it goes in. THEN SELL THE KLUNKER POST HASTE! Or keep it (as in my case) ;-)


Depending on how much money you want to spend there are "threadless
bottom brackets" that are intended for the repair of damaged bottom
brackets. One source states that "Grand Cru threadless bottom brackets
fit most frames, even those with Swiss threading. And they work on
frames with damaged BB shells, even if the existing threading is
totally stripped."

see
https://store.velo-orange.com/index....-brackets.html
--
Cheers,

John B.

 




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