RADBMX.CO.UK

Technical & Reference Section => Tech and Restoration => Topic started by: BossHogg on September 17, 2007, 08:04 PM

Title: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: BossHogg on September 17, 2007, 08:04 PM
Hi all,

I've got this set of single pinch Redline 401's. Bit of rust here and there but pretty good nick overall.........well apart from this crack in the non-drive arm. :(
(http://www.radbmx.co.uk/archive/albums/bb318/jameshogg71/DSC01126.jpg)
(http://www.radbmx.co.uk/archive/albums/bb318/jameshogg71/DSC01123.jpg)

Anyone know if this damage can be fixed up and made good enough to ride on again?  The crack looks to be in a pretty tricky spot alright.  Could be some issues with any repairs being put under tension in that spot right there, i dunno.

Any expert opinions appreciated.

Cheers - Jim  :daumenhoch:


 

Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: CD17 on September 17, 2007, 08:08 PM
Im sure that could be fixed if you know a good tig wilder, but it would take a bit of work to get it looking right  :-\

Or even a good tig welder  ;)
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: billstup on September 17, 2007, 08:36 PM
I recon it could be repaired for show purposes, but I wouldn`t like to ride on them  :(
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: bmx xxx on September 17, 2007, 08:55 PM
i recon super super glue would do, well worth repairing though, good luck
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: sawzall on September 17, 2007, 09:09 PM
that should repair ok,the crack would need to be veed out then tig welded,then the thread would need to be re-tapped ;)
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: mark 2 on September 17, 2007, 09:14 PM
Be careful with a re-tap if it get's drilled again for the thread you'd lose too much of the original metal and then have to go up a size and knob about with different hardware for that side. Try a little weld and get it filed and polished out then a rechrome.
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: TwoBobRob on September 17, 2007, 09:41 PM
No tapping there surely?   It must be a clearance hole....  Tapped thread is on t'other bit   ;)


As for the repair, stick it in the post to Fuzzynod, have his mate repair it, then I'd say ride on it no worries  :)
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: sawzall on September 17, 2007, 10:03 PM
just noticed it was on the non thread side :D
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: mark 2 on September 17, 2007, 10:05 PM
yes, well spotted :LolLolLolLol:
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: SaMAlex on September 17, 2007, 10:09 PM
I had a crank arm rewelded (not a 401). The weld was spot on but the heat distorted the spindle boss and it didnt fit over the spindle!! Just a little something to watch out for.
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: RATTY on September 17, 2007, 10:13 PM
Before you go to the expense of welding and rechroming, there is usually a good supply of orphan arms on ebay, might be a cheaper route :daumenhoch:
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: SaMAlex on September 17, 2007, 11:23 PM
there is usually a good supply of orphan arms on ebay

Does this thread, and this comment, answer the "which is better, flights or profiles?" Question?
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: Bob_Acid on September 18, 2007, 12:22 AM
Aye, does a bit don't it?
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: BossHogg on September 18, 2007, 01:03 PM
Cheers fella's,

Plenty of food for thought there  :-\

Any ideas on cost of repair and a re-chrome vs cost of an orphan?

I was lookin to use the cranks for a rider but if there's any strength issues, maybe not.

Might just be best looking for another arm what with the cost for repair and re-chrome, and if the thing does warp from the heat and won't fit the spindle then it's neither use nor ornament eh?

Shame not to try a fix though.......

.......Bugger :buck2:

Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: TwoBobRob on September 19, 2007, 01:07 AM
Another arm is of course the easiest fix, but for a rider you could always just weld the thing and not bother about a rechrome. It'll hardly notice really. As for the heat distortion, the right welder will keep this to a minimum. Also as the splines are so very coarse, I suspect it'll always fit without much hassle   ;)
Title: Re: Redline 401 Crank Arm - Cracked Pinch Bolt
Post by: gjs on September 22, 2007, 04:28 PM
I have a pair of 401's that the arm completely snapped off,which I welded back on without rechroming,doesn't get used but I would use for everday riding no jumps etc.The repair for yours would make any difference to the strength of the crank,I don't think :daumenhoch:
(http://)(http://www.radbmx.co.uk/archive/albums/b375/nogoodthis/DSCF0429.jpg)
SimplePortal 2.3.5 © 2008-2012, SimplePortal