Author Topic: Fork leg straightening  (Read 446 times)

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Offline craigclayton

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Fork leg straightening
« on: January 11, 2018, 10:36:36 PM »
Any recommendations for straightening a fork leg in Melbourne
Cheers C
74 Bultaco 250, 77 RM125b

Offline matcho mick

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Re: Fork leg straightening
« Reply #1 on: January 12, 2018, 09:45:48 PM »
Lightfoot Engineering??,down there somewhere?? :P
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Offline Momus

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Re: Fork leg straightening
« Reply #2 on: January 13, 2018, 02:23:04 AM »
Ian at Detroit Flame Hardening in Moorabbin straightens steel axles after heat treating; he may do your stanchion.

Offline PEZBerq

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Re: Fork leg straightening
« Reply #3 on: January 13, 2018, 11:04:51 AM »
No need to heat treat a fork tube of course.
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Offline YSS

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Re: Fork leg straightening
« Reply #4 on: January 13, 2018, 01:29:38 PM »
Conventional forks (thick walls ) are easy to straighten between V-blocks . For thinner walls V-blocks can distort the walls . You can overcome that by making half cups that will take the correct tube size .  When you get them hard chromed they also get straightened before pregrinding  and then of course the finished product is 100% straight like new . No marks and  no hair line cracks in the chrome .
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Offline craigclayton

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Re: Fork leg straightening
« Reply #5 on: January 15, 2018, 07:11:12 PM »
Ok upper fork leg has now been straightened but now sticks even more in lower leg, so I’m thinking lower leg needs straightening. Problem is lower leg is tapered on the outside so cannot see where bend is.
Any suggestions
C
74 Bultaco 250, 77 RM125b

Offline Momus

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Re: Fork leg straightening
« Reply #6 on: January 15, 2018, 11:28:49 PM »
Look for the rub witness and hone the leg with a brake cylinder hone if only slight. Other method would involve sliding the leg over the straight stanchion and heating to relieve it.

Offline tony27

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Re: Fork leg straightening
« Reply #7 on: Yesterday at 10:33:51 AM »
I'd try other stanchion in the lower first to confirm that the lower is the problem

Offline sleepy

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Re: Fork leg straightening
« Reply #8 on: Yesterday at 11:02:36 AM »
Sounds like it's time to get your own dial indicator and basic V blocks so you can check it yourself.
If it's worse after straightening could have been distorted during the straightening process. I've been doing them for about 40 years and some can be quit difficult to get straight. As was mentioned earlier about using V blocks to support in press is a bad idea, need machined half cups to match diameter of fork.
I have seen quite a few bent bottoms that can't be fixed and some that can be honed if they have a dent in them.

Offline bazza

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Re: Fork leg straightening
« Reply #9 on: Yesterday at 03:35:32 PM »
as sleepy said
Once you go black  you will never go back - allblacks
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Offline Momus

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Re: Fork leg straightening
« Reply #10 on: Yesterday at 07:45:14 PM »
A straight edge and eyeball is all that is required to check the stanchion.