Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: AMuzi Newsgroups: rec.bicycles.tech Subject: Re: Machine Shop Date: Tue, 4 Mar 2025 14:07:12 -0600 Organization: Yellow Jersey, Ltd. Lines: 150 Message-ID: References: <4edkrj13v11bkgfpmgcr58psf6v64j906f@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 04 Mar 2025 21:07:12 +0100 (CET) Injection-Info: dont-email.me; posting-host="6062ce5ab24ada80c861793245b7922c"; logging-data="2132346"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19to7hcdDgvZlI95bNzUFKh" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:L3/sD/z/50siUY8eY34B+z4g7ho= In-Reply-To: Content-Language: en-US Bytes: 6798 On 3/4/2025 11:24 AM, Zen Cycle wrote: > On 3/4/2025 12:44 AM, AMuzi wrote: >> On 3/3/2025 5:30 PM, Jeff Liebermann wrote: >>> On Sat, 22 Feb 2025 17:21:55 -0500, Frank Krygowski >>> wrote: >>> >>>> On 2/22/2025 4:06 PM, Jeff Liebermann wrote: >>>>> On Sat, 22 Feb 2025 19:58:29 GMT, cyclintom >>>>> >>>>> wrote: >>>>> >>>>>> On Fri Nov 8 14:03:46 2024 Frank Krygowski  wrote: >>>>>>> It doesn't exist, Tom. You can't pop a dent out a >>>>>>> bicycle frame tube by >>>>>>> riding the bike. Thinking you can is a sign of insanity. >>>>>> >>>>>> If you have a slight dent in high performance steel. >>>>>> the tubing can revert to its natural shape under stress. >>>>> >>>>> Tom.  The only steel that might do that is spring steel >>>>> (1095, 1060, >>>>> 1075, 1080, etc).  Bicycle frames are not made from >>>>> spring steel.  If >>>>> they were made from spring steel, they would ride like >>>>> the proverbial >>>>> wet noodle. >>>>> >>>>> So, what's the SAE/AISI number for such a spring steel >>>>> bicycle frame >>>>> and who is selling such bicycles? >>>>> >>>>> Since you claim that you fixed the dent on YOUR >>>>> bicycle, could I >>>>> trouble you for the maker and model number of this >>>>> bicycle so I can >>>>> determine steel alloy that was used?  Some photos of >>>>> the dent, before >>>>> and after, would also be nice. >>>>> >>>>> Note that I'm not talking about shape memory metal alloys: >>>>> >>>>> >>>>> I'm also not talking about hydroforming, which doesn't >>>>> work at >>>>> removing dents in steel tubing without high pressure >>>>> hydraulic >>>>> assistance.  It's commonly used for bending aluminum >>>>> frames.  You >>>>> obviously don't have the necessary equipment in your >>>>> garage workshop >>>>> because you claimed that the dent popped out after >>>>> simply riding the >>>>> bicycle: >>>>> >>>> ding-removal.html> >>>>> >>>>>> Where the hell do you get off not knowing the >>>>>> properties of tempered steel and commenting on it? >>>>> >>>>> Frank, he's all yours now. >>> >>>> Sorry, I'm going to disagree with you about spring >>>> steel. AFAIK there is >>>> _no_ steel that would spontaneously cure a dent in a >>>> bicycle tube from >>>> riding stresses. If the steel is dented, it's been >>>> stressed in that >>>> location beyond its yield point. There's no practical >>>> way for that to >>>> spontaneously reverse itself. >>> >>> That's correct.  However, you're reading too much into my >>> mention of >>> 1095 steel being "spring steel". >>> >>> 1095 is a steel alloy that can be used for making steel >>> springs.  It >>> can also be used for making knife blades, where the a >>> springy steel >>> makes the blade more durable.  The major difference is >>> the steel >>> spring is fairly thin, while the knife blade is much >>> thicker.  Same >>> spring effect, but very different products. >>> >>>> While Andrew knows much more than I about the applicable >>>> shop >>>> techniques, I think you might be able to partially >>>> remove a dent in a >>>> tube if, like a seat tube, you had access to an open >>>> end. Perhaps >>>> forcing in a series of mandrels of increasing diameter >>>> could gradually >>>> force the dent outward. (Something similar is done to >>>> repair dents in >>>> the tubing of brass instruments like trumpets.) But I >>>> doubt it would >>>> give a perfect result, and I think cosmetic repair >>>> (maybe Bondo?) would >>>> be needed to get it really pretty. >>> >>> Some kind of flexible automobile body putty (usually an >>> epoxy) would >>> work.  I had the left seat stay, on my Miyata 610 touring >>> bicycle, >>> repaired professionally.  I didn't paint it.  I'm sure if >>> I had, there >>> would be no evidence of the repair remaining. >>> >> Miyata-610.JPG> >>> It's the rust colored section of the left seat stay. >>> Unfortunately, I >>> didn't see the work and cannot describe how it was done. >>> >>>> What Tom is describing is his usual mix of lying and >>>> fantasy and ignorance. >>> >>> Yep.  After so many years of cultivating Tom's fertile >>> imagination, >>> all that has grown were poisonous flowers and ugly weeds. >>> >>> >> >> For a typical dent, this Waterford for example: >> http://www.yellowjersey.org/wfd12a.jpg >> >> the tube is rolled to reform the greater part of the >> deformation: >> >> http://www.yellowjersey.org/wfd12b.jpg >> >> then the remaining low spots are filled with polyester >> bondo or with metal (brass, silver, lead. I use lead): >> >> http://www.yellowjersey.org/wfd12c.jpg >> >> and finished: >> >> http://www.yellowjersey.org/wfd12e.jpg >> > >  Would you consider this type of repair on an aluminum frame? > Nope. Someone else might but it's really not my area. -- Andrew Muzi am@yellowjersey.org Open every day since 1 April, 1971