Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: toontra on 08 November, 2008, 03:26:08 pm
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Anyone know where I can get hex bolts (for standard frame braze-ons, rack-mounts, etc) with washers attached? You find them on some stem face-plates and other accessories.
I'm fed up of my rack bolts shaking loose and dropping out, and if I use separate split-ring washers they get lost when I take the bolts out. As I take the rack off regularly I don't want to use any kind of glue.
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Blue Loctite Threadlocker (http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10151&storeId=10001&partNumber=526632&langId=-1&source=td) is strong enough to stop a bolt shaking loose without preventing you from removing and refitting, and you don't have to keep re-applying it. It still works when dry. It works by bunging up the thread and adding friction, rather than being a glue. Don't saturate the whole thread if you don't want the bolt too hard to remove.
It is a good idea to use washers anyway. Sorry I don't know where to find bolts with washers attached right now.
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Ta-da!
Socket Cap Head Screw with Captive Washers - Product Picture From Zhejiang Jinggu Standard Part Co., Ltd. (http://jinggu.en.alibaba.com/product/50117572/51517723/Sem_Screws/Socket_Cap_Head_Screw_with_Captive_Washers/showimg.html)
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Ta-da!
Socket Cap Head Screw with Captive Washers - Product Picture From Zhejiang Jinggu Standard Part Co., Ltd. (http://jinggu.en.alibaba.com/product/50117572/51517723/Sem_Screws/Socket_Cap_Head_Screw_with_Captive_Washers/showimg.html)
Yes, those are the things, but those particular ones are too long for cycle use I think - they would foul the cassette if using as rack mounts and would probably be too long for my skinny steel frame.
I tried fiddling about looking for alternatives on the website but no luck. I'd email them but I don't know what diameter or thread bicycle bolts are!
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Do you have a vice and junior hacksaw (with 32 tpi blade)? It's dead easy to shorten a screw if so. Screw a nut on first - which cleans the thread when unscrewed.
Or buy a bag of 100 washers - then it won't matter if you loose a set every time!
M5 is most common for rack fixings.
Here are some titanium ones! (http://cgi.ebay.co.uk/NEW-Amoeba-Titanium-Ti-Bolt-M5-18mm-w-washer-1pc_W0QQitemZ230297588530QQcmdZViewItem?hash=item230297588530&_trksid=p3286.m63.l1177)
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Not sure how you reason, those flat washer do nothing to prevent the bolts to unscrew! ???
Biggsy's right, use Loctite threadlock - it is the only thing that last. Similar compound is used by the industry for example on the bolts that attach the brakes to the frame, as the manufacturer might get sued if these go missing! ;)
edit:
Another better way is to tread a extra long bolt from the inside of the dropouts and put a nylock-nut on the outside! That way you never lose the bolt and if it break you can easily remove what remain. I would still use thread locking compound as it also prevent the threads to oxidise/rust.
Also use big washers to spread the load to a larger surface to prevent cracks on the rack. That's what they are for...!
Just make sure the head of the bolt clears the chain on the drive side. :thumbsup:
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Not sure how you reason, those flat washer do nothing to prevent the bolts to unscrew! ???
Biggsy's right, use Loctite threadlock - it is the only thing that last. Similar compound is used by the industry for example on the bolts that attach the brakes to the frame, as the manufacturer might get sued if these go missing! ;)
edit:
Another better way is to tread a extra long bolt from the inside of the dropouts and put a nylock-nut on the outside! That way you never lose the bolt and if it break you can easily remove what remain. I would still use thread locking compound as it also prevent the threads to oxidise/rust.
Also use big washers to spread the load to a larger surface to prevent cracks on the rack. That's what they are for...!
Just make sure the head of the bolt clears the chain on the drive side. :thumbsup:
Yes, this all makes sense. I was probably looking for a solution that didn't exist. As you say, the flat "captive" washers probably don't help shaking loose but rather are to spread the load. I probably just need split (or wrinkled) washers.
If I was going a long trip then your advice about the lock nut on the outside is a good one. However I need to take the rack off regularly (and quickly). Also my bottle cage bolts shake loose and this solution wouldn't work there.
Are people sure that Loctite Threadloc continues to work after the bolt has been removed several times? Seems a bit counter-intuitive to me.
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Threadlock isn't necessary if you can get a bolt really tight because then there is enough compression in the threads to make it such a tight fit that it won't shake loose. Grease helps you get a bolt tight*. But you can't always, or don't always want to tighten a bolt that much (e.g. when afraid of stripping the thread or rounding the head), then threadlock is handy.
I use threadlock sometimes. It works best when applied wet, but does still work quite well when it's dry as the bolt is fitted - you can feel extra friction as extra force is needed to turn the allen key. You might want to add some more after a few removals and refits if some of it has scraped off.
* If you currently fit your bolts dry, you could try grease before resorting to threadlock. How's that for counter-intuitivity!
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Why are you using washers at all?
Bolt Science (http://www.boltscience.com/) suggests that "plain washers are best avoided if possible and certainly, a plain washer should not be used with a 'lock' washer" (http://www.boltscience.com/pages/faq.htm#11) and "conventional spring lock washers are no longer specified, because it has been shown that they actually aid self loosening rather than prevent it" (http://www.boltscience.com/pages/vibloose.htm).
If you are taking your rack off frequently, you may have damaged the threads on the frame so there is play between the bolt and threaded hole. In this case try using a slightly long nut and fitting a nut to the end that sticks through the frame (a nyloc nut might be best).
[edit: I just noticed Mr. Pither suggests nyloc nuts too.]
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Wow. Having just watched the Bolt Science video I'm sure that the split washer is not the way to go. However, they didn't mention the crimped washer (usually a darker colour and thinner material). I have to say that from my personal experience a bolt fitted with one of these has never worked loose. Not very scientific I know, but many, many times rack or bottle cage bolts on thier own have loosened, and on 3 occasions fallen out altogether, twice with bad consequences.