OzVMX Forum

Clubroom => Tech Talk => Topic started by: craigclayton on January 11, 2018, 10:36:36 pm

Title: Fork leg straightening
Post by: craigclayton on January 11, 2018, 10:36:36 pm

Any recommendations for straightening a fork leg in Melbourne
Cheers C

Title: Re: Fork leg straightening
Post by: matcho mick on January 12, 2018, 09:45:48 pm

Lightfoot Engineering??,down there somewhere?? :P

Title: Re: Fork leg straightening
Post by: Momus 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.

Title: Re: Fork leg straightening
Post by: PEZBerq on January 13, 2018, 11:04:51 am

No need to heat treat a fork tube of course.

Title: Re: Fork leg straightening
Post by: Wasp 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 .

Title: Re: Fork leg straightening
Post by: craigclayton 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

Title: Re: Fork leg straightening
Post by: Momus 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.

Title: Re: Fork leg straightening
Post by: tony27 on January 16, 2018, 10:33:51 am

I'd try other stanchion in the lower first to confirm that the lower is the problem

Title: Re: Fork leg straightening
Post by: sleepy on January 16, 2018, 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.

Title: Re: Fork leg straightening
Post by: bazza on January 16, 2018, 03:35:32 pm

as sleepy said

Title: Re: Fork leg straightening
Post by: Momus on January 16, 2018, 07:45:14 pm

A straight edge and eyeball is all that is required to check the stanchion.

Title: Re: Fork leg straightening
Post by: craigclayton on January 17, 2018, 10:23:49 am

Well managed to sort it, I bought a brake honing tool from the local car parts shop. I identified where it was sticking and honed from that point down. 30 minutes of honing, cleaning and then checking and now fixed.
Thank you all for your help
C