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Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Frank Krygowski <frkrygow@sbcglobal.net> Newsgroups: rec.bicycles.tech Subject: Re: Stuck BB Date: Tue, 17 Sep 2024 22:11:23 -0400 Organization: A noiseless patient Spider Lines: 95 Message-ID: <vcdcsb$3rsol$1@dont-email.me> References: <vc9riq$2vnl9$1@dont-email.me> <vc9v87$2vi8l$4@dont-email.me> <vca3mv$31h84$2@dont-email.me> <vcbt40$3gqp9$1@dont-email.me> <vcbv4o$3h5s3$2@dont-email.me> <vccn3c$3gqp9$2@dont-email.me> Reply-To: frkrygow@gmail.com MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 18 Sep 2024 04:11:24 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5aee23de4c420d561d19952da48c6468"; logging-data="4059925"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19FcFaHa2NYRd9dmRGQHY3UaiCDKv2l1yA=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:9oQFza2Qnd0VqBtRvzFNx6Yh2Ac= Content-Language: en-US In-Reply-To: <vccn3c$3gqp9$2@dont-email.me> Bytes: 5527 On 9/17/2024 3:59 PM, Zen Cycle wrote: > On 9/17/2024 9:10 AM, AMuzi wrote: >> On 9/17/2024 7:36 AM, Zen Cycle wrote: >>> On 9/16/2024 4:16 PM, AMuzi wrote: >>>> On 9/16/2024 2:00 PM, Zen Cycle wrote: >>>>> On 9/16/2024 1:57 PM, Mark J cleary wrote: >>>>>> My Wilier has a stuck right cup BB. At the moment the cranks spin >>>>>> fine. It has an FSA Mega Exp crankset that is the one that is not >>>>>> pinch bolts but uses self extracting allen key to put on drive >>>>>> side crank arm. Has the wavy washer in the set up. I think that is >>>>>> why the bearings went bad because it allows moisture to get in not >>>>>> sealed like a regular shimano crank and external BB. >>>>>> >>>>>> The BB is of course and external BB from FSA. The let side cup >>>>>> bearings went bad so I used a Shimano BB60 cup because I had a >>>>>> spare one. The crankset works beautiful now. However I would like >>>>>> to simply try and use the whole Shimano BB60 bracket. I cannot >>>>>> however get the right side cup off. I realize it is left hand >>>>>> threaded but it is really stuck. I tried putting in a vice and >>>>>> using the bike to turn but no luck. >>>>> >>>>> I was going to suggest that. >>>>> >>>>> >>>>>> I have managed to chew the notches pretty good but it will take >>>>>> the wrench at this point. >>>>>> >>>>>> Any suggestions on how to get the cup free. I actually think it >>>>>> would be easier to simply hacksaw the cup and take it out but I >>>>>> don't want to mess up the treads in BB of the bike. I will take >>>>>> any and all suggestions on how to get this cup off. At the moment >>>>>> the cranks spin fine because the bearings are fine on the right >>>>>> side cup but I just don't like the set up. I may even go to a >>>>>> shimano R7000 crankset. ] >>>>> >>>>> >>>>> I'm sure Andrew may have some sage advice, but if you're beginning >>>>> to see damage to the cup, I'd suggest taking it to a shop. >>>>> >>>>> If you still want to DIY, get one of these to match your threading >>>>> first. >>>>> >>>>> https://www.amazon.com/HOZAN-C-402-Bottom-Bracket-Tap/dp/ B000BSBSLQ/ >>>>> >>>> >>>> Some people do like owning esoteric tools but I strongly dissuade >>>> most customers from buying dies, reamers, mills, taps. They are only >>>> and always subtractive, that is, they can (and often do) damage >>>> material but they cannot add material. >>>> >>>> In his aluminum shell, >>> >>> Something else just occurred to me - If his frame is aluminum and the >>> bearing cup is aluminum, it may have galled. In that case, even >>> notching the cup isn't going to work. In fact, doing so may damage >>> the cup such that it won't be possible to replace the bearing, you'll >>> basically have to toss the thing. >>> >>> The question is, how do you tell if it's galled or just stuck from >>> corrosion or some adhesive? >>> >>>> a small stainless brush is plenty for cleaning up crud from the >>>> threads. >>> >>>> >>>> https://www.sears.com/forney-70488-wire-brush-stainless- steel-with- >>>> plastic/p-00920078000P >>>> >>> >> >> Even with a lot of displaced material, a slit or at the extreme two of >> them will relieve the pressure and allow removal. >> > > I'm not an ME, but that's not how I understood galling works. I was told > the two surfaces bond on the molecular level, I suppose one might be > able to 'peel' the two components apart, but that would either leave > and/or remove enough material such that the remaining threads would be > likely damaged beyond use. > Not being an expert in this area, I might have some misunderstanding. I'm a Mechanical Engineer, but I think we need a Metallurgical Engineer at this point. But we've been talking about parts that are not in motion. As I understand it, galling requires relative motion. The problem with aluminum and steel, as in this situation, is different. It's a layer of aluminum oxide forming at the interface, which adds thickness to the aluminum and causes the aluminum component to essentially clamp onto the steel component. AFAIK there's no metal-to-metal bonding. But it's a famous problem with aluminum seatposts in steel frames. Searching online will show that problem is pretty common and quite difficult. -- - Frank Krygowski