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Technical & Reference Section => Tech and Restoration => Topic started by: RATTY on July 16, 2007, 06:40 PM

Title: Flite crank help??
Post by: RATTY on July 16, 2007, 06:40 PM

Well, I am gutted. I managed to snap the chain-ring bolt that locks the chain-ring to the crank arm. Its an original redline bolt so would be hardened steel. Has anyone managed to drill a hardened bolt out before? Got any hints or tips before I start to cry :'( Oh and has anyone got a spare bolt just in case I can get it out :daumenhoch:

Title: Re: Flite crank help??
Post by: theRuler on July 16, 2007, 06:57 PM

is it an old school flite or a new twin pinch?

Title: Re: Flite crank help??
Post by: RATTY on July 16, 2007, 07:04 PM

Single pinch, 80s, shouldnt have been racing on them, gutted now..

Title: Re: Flite crank help??
Post by: theRuler on July 16, 2007, 07:11 PM

no worries
get the arm off
if the bolt is proud you are laughing
either way it shouldn't be tight in the hole!

i reckon it's an m8 bolt, like a stem bolt

get one of them and file it down a bit

it doesn't need to be super tight, but put some threadlock on it

Title: Re: Flite crank help??
Post by: RATTY on July 16, 2007, 07:19 PM

Gra, its broken about 5mm inside the arm, and its imperial sizes, I found the head of the bolt, so I will try locktite first, but it broke under pressure and looks well chewed

Title: Re: Flite crank help??
Post by: bof on July 16, 2007, 07:21 PM

It wont be metric Im sure of that. It should be really easy to take out. Just use a punch or a small metal chisel and tap it round until it comes out. then when there is enough to grab grab it with pliers or mold grips and carry on turning. or another alternative is to hacksaw across the top of it and take it out with a screwdriver. :)

Title: Re: Flite crank help??
Post by: theRuler on July 16, 2007, 07:22 PM

buy an internal stud extractor

you drill a 1/8" hole in the bolt, then screw in the extractor - when it bites it starts to undo (as it screws in opposite)

Title: Re: Flite crank help??
Post by: GREMLIN on July 16, 2007, 07:23 PM

As above  ;)

Title: Re: Flite crank help??
Post by: RATTY on July 16, 2007, 07:46 PM

I was going to try the stud extractor but what i needed to know was can you drill hardened steel?

Title: Re: Flite crank help??
Post by: GREMLIN on July 16, 2007, 07:57 PM

I should think so. The Redline bolts aren't the toughest. The 401's i bought the other week had to go to an engineers to have a snapped off bolt removed the day before i got hold of them  :daumenhoch:.  G.

Title: Re: Flite crank help??
Post by: showtime on July 16, 2007, 08:26 PM

try a left handed drill bit Tony
as soon as it bites into the remains of the bolt it should unwind it right out  ;)

you obviuosly need a reversible drill to do this though mate!

Title: Re: Flite crank help??
Post by: Rombloke on July 16, 2007, 09:01 PM

exactly what adam said....good engineer supplies should do the bit

Dave

Title: Re: Flite crank help??
Post by: RATTY on July 16, 2007, 10:32 PM

Cheers guys,  :daumenhoch:

Title: Re: Flite crank help??
Post by: Gary72 on July 16, 2007, 10:46 PM

should be able to get my hands on some stud extractors from work if you want, save buying, what damage did it do to the chainring???


I saw this happen and he went over the bars :LolLolLolLol: :LolLolLolLol:


Also the comment from a lady at the side was "Imagine if that had been a kid" :idiot2:

Title: Re: Flite crank help??
Post by: RATTY on July 16, 2007, 11:52 PM

Yes please Gaz, I just hope I can do it in time for thursday night :daumenhoch:

Title: Re: Flite crank help??
Post by: Webdawg on July 17, 2007, 12:46 AM

Pretty sure i have enuff Redline stuff to fix this  babe, 4 sets of single pinch bolt flights n Ti axles n all will be happy by Thursday :)

Title: Re: Flite crank help??
Post by: diesel on July 17, 2007, 09:05 AM

Steve:

I should have a spare bolt kicking around, if you can't get hold of one give me a shout

Dan