Max Quinn Posted June 13, 2005 Report Share Posted June 13, 2005 Hey the chainring bolt (i think thats the name? It bolts the chainring to the cranks arm) on my BMX is an allenkey bolt and has rounded off so that a 5mm allen key slips around but a 6mm still won't quite fit, i need to get it off to fit my new sprocket but i don't have a clue how? Is there any methods of getting it off and if the method involves destorying the bolt where would i go to get hold of a new one? Thanks very much, Max. Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted June 13, 2005 Report Share Posted June 13, 2005 use the search...and go to your bikeshop/nick it off another bike :mellow: there's loads about getting bolts out.. adam Quote Link to comment Share on other sites More sharing options...
Corish Posted June 13, 2005 Report Share Posted June 13, 2005 Smack a torch drive in if you have one thats just a little bigger than the rounder bolt. Quote Link to comment Share on other sites More sharing options...
Max Quinn Posted June 13, 2005 Author Report Share Posted June 13, 2005 Smack a torch drive in if you have one thats just a little bigger than the rounder bolt. ← Sorry i haven't a clue what one of them is so i doubt i'll have one. :mellow: use the search...and go to your bikeshop/nick it off another bike pinch.gif there's loads about getting bolts out.. adam ← I searched but can't really seem to find anything specific enough to help me, was waiting for someone to say that though :-. Thanks for any help, Max. Quote Link to comment Share on other sites More sharing options...
Ashley Smith Posted June 13, 2005 Report Share Posted June 13, 2005 Smack a torch drive in if you have one thats just a little bigger than the rounder bolt. ← either try that or have the bolt machined out with a carbide cutter, thats how we get broken bolts out at work :mellow: regards ash Quote Link to comment Share on other sites More sharing options...
Corish Posted June 13, 2005 Report Share Posted June 13, 2005 Its Torx, not Torch silly me. Heres what they look like: :mellow: Quote Link to comment Share on other sites More sharing options...
Sam Nichols Posted June 13, 2005 Report Share Posted June 13, 2005 OR just get loads of allen keys together (metric and imperial) then find one that fits reasonably snuggly - then fill the bolt with super glue and stick the allen key in and put superglue around the edges and what not. Leave it for an hour or so to be sure it has definitely dried, then away you go :mellow: Quote Link to comment Share on other sites More sharing options...
Ashley Smith Posted June 13, 2005 Report Share Posted June 13, 2005 OR just get loads of allen keys together (metric and imperial) then find one that fits reasonably snuggly - then fill the bolt with super glue and stick the allen key in and put superglue around the edges and what not. Leave it for an hour or so to be sure it has definitely dried, then away you go :mellow: ← not sure superglue would work like but try it at least if not another way would be to put an old smaller allen key into the bolt head then put a tack of weld onto the bolthead and the allen key and then it should be fine............. :- regards ash Quote Link to comment Share on other sites More sharing options...
guineasmithpig Posted June 13, 2005 Report Share Posted June 13, 2005 East Outs don't faff about. get some/one o these. makes the job far far easier. similar to a thread tapping tool, but with an anti-clockwise thread. so u drill a hole smaller in diameter than the bolt through the head downwards, and screw in the Easy Out until it gets to wide for the hole. keep twistin and it unscrews the bolt. saves u supergluin the bolt in by mistake, or meltin anythin tryin to weld somethin to the top. Easy peasy. i would get a set maself, but i don't round bolts of (N) smithy Quote Link to comment Share on other sites More sharing options...
JIX Posted June 13, 2005 Report Share Posted June 13, 2005 If/when I round bolts off I just find a screwdriver that is just bigger than the allen key slot and bang it in with a hammer. It should cut into the softer metal of the bolt, and then you can twist it out. Quote Link to comment Share on other sites More sharing options...
Ali C Posted June 13, 2005 Report Share Posted June 13, 2005 get a hacksaw, cut a slot in the bolt and remove with a screwdriver, that usually works if you have good access to the bolt Quote Link to comment Share on other sites More sharing options...
guineasmithpig Posted June 13, 2005 Report Share Posted June 13, 2005 It should cut into the softer metal of the bolt, and then you can twist it out. or it cud knacker the end of ur screwdriver, renderin it useless for, saaaaay, screwin screws? (i love u jaime) haha. if u do this, use an old one. but i'd love to know, if u can undo it with a screwdriver, how do u manage to round it off with an allen key? (N) smithy Quote Link to comment Share on other sites More sharing options...
tipsy Jock Posted June 13, 2005 Report Share Posted June 13, 2005 get a hacksaw, cut a slot in the bolt and remove with a screwdriver, that usually works if you have good access to the bolt ← None of these fancy pants ideas, Hacksaws all you need (N) Quote Link to comment Share on other sites More sharing options...
RicH_87 Posted June 13, 2005 Report Share Posted June 13, 2005 get a hacksaw, cut a slot in the bolt and remove with a screwdriver, that usually works if you have good access to the bolt ← ditto, that's what i was going to suggest when i opened the thread so just backing Ali c up. (N) if you're careful you may be able to re-use the bolt and re tighten it using the screwdriver. Quote Link to comment Share on other sites More sharing options...
Bionic Balls Posted June 13, 2005 Report Share Posted June 13, 2005 go easy with the grooooove you cut...you can make it a whole lot worse by twisting off half of the head (N) if you do...there is usually a "bump" where the head was and if careful, you can hit this round with a chisel (and hammer) thus undoing ze bolt. Otherwise, drill a hole in though it and getting it out become sooo much easier. adam Quote Link to comment Share on other sites More sharing options...
JIX Posted June 13, 2005 Report Share Posted June 13, 2005 but i'd love to know, if u can undo it with a screwdriver, how do u manage to round it off with an allen key? With the power of 20 men!!!!! Some times bolts get rounded through repeated bad tightening and retightening. Like not putting the allen key in proper like. Once you got the screwdriver in properly you can attatch some mull grips and other such devices. (love you too smithy) Quote Link to comment Share on other sites More sharing options...
yoyoyo Posted June 13, 2005 Report Share Posted June 13, 2005 a 5mm allen key slips around but a 6mm still won't quite fit, ← Dont suppose youve got a 5.5 mm allen key Quote Link to comment Share on other sites More sharing options...
Max Quinn Posted June 13, 2005 Author Report Share Posted June 13, 2005 Dont suppose youve got a 5.5 mm allen key ← Nah that's what i was thinking a minute ago. Can you get them? I'll try some of the other ideas but i don't really have access to welding thingamibobs and suchlikes. No idea how the bolt got rounded, it's a second hand bike and this is the first time i've needed to take the chainring bolt off. Thanks for all your help, Max. Quote Link to comment Share on other sites More sharing options...
JTM Posted June 13, 2005 Report Share Posted June 13, 2005 An imperial shitty allen key that is slightly too big, hammer it in and then there you go Quote Link to comment Share on other sites More sharing options...
Phatmike Posted June 13, 2005 Report Share Posted June 13, 2005 None of these fancy pants ideas, Hacksaws all you need :D ← *Angle grinder. Simply anglegrind (or dremmel if you're being dainty) the head of the bolt off, so it will allow the chainring to slide over the top. You'll then be exposed with a few mm (depending on the thickness of the chainring) of bare thread, with no pressure on it, which you will be able to unscrew by hand. (N) All this will take about 5 seconds, tops. Dont suppose youve got a 5.5 mm allen key ← I've got one, if you're not man enough to get out the power tools, and none of the other methods work, give me a Pm, and i'll fire it your way. Mike. (Y) Quote Link to comment Share on other sites More sharing options...
Ali C Posted June 13, 2005 Report Share Posted June 13, 2005 the bolt that fitted my chainring onto my bmx was impirial, so maybe yours isnt rounded but just needs an impirial allen key? Quote Link to comment Share on other sites More sharing options...
Swize Posted June 13, 2005 Report Share Posted June 13, 2005 (edited) Hacksaw the bolt head so you can the put a flat headed screwdriver in, and then unscrew it. Edit: Oh crap, i've seen lots of other people have suggested this lame idea, sorry for posting! Sam Edited June 13, 2005 by samthebiker Quote Link to comment Share on other sites More sharing options...
will Posted June 13, 2005 Report Share Posted June 13, 2005 Scenario 2: I have the same issue however the top of the bolt is below the top of the chainring, so sawing grooves, angle grinding wouldnt work. Also the chainring bolt in there is ~2years old and was initially put in with loctite. :"> The chainring does need replacing so if destroying it with a grinder is the only option then so be it (N) Any ideas on how to extract bolt and salvage chainring? Will. Quote Link to comment Share on other sites More sharing options...
onzamad Posted June 14, 2005 Report Share Posted June 14, 2005 use a hammer and a small chissel, be very careful but you can actually turn the head of the bolt by hitting the bolt anticlockwise, using the chisel, it takes a while but it does work, i have had to do it before. if you are struggling use a small dot punch instead of the chisel, this should give you enough clearance, but if i was you the best way would probably to get the imperial equivelant of 5mm/5.5mm, thats either 13/64 for 5mm or 7/32 for 5.5mm, hope that helped. Quote Link to comment Share on other sites More sharing options...
biketrialler Posted June 14, 2005 Report Share Posted June 14, 2005 Superglue works fine, just put an allen key in, loads of glue, let it dry overnight then turn the bolt out in the morning :( Does the job fine. Thanks. Tim Henman. Quote Link to comment Share on other sites More sharing options...
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