Getting parts machined?

..... · Quote Me Happy Joined: 15 Jan 2005 Karma :

After a bit of drunken ebaying I have some parts for my bike that don't really fit. However, with the Yanks being the ambitious chaps that they are, many of them have done the same thing and have kindly produced some drawings to help me out.

I'm putting a set of CR250 forks onto my XR. This seems a well documented process over on some Yank forums. I need to get a CR steering stem machined to fit into the CR yokes but accept XR bearings so it can fit the frame IYSWIM.

A chap over on Thumpertalk has produced these pictures -

Standard CR Stem

https://img.photobucket.com/albums/v619/baldgit/crstem.jpg

What the modified CR stem should end up like

https://img.photobucket.com/albums/v619/baldgit/crstemmodified-1.jpg

And a bushing needs to be made up to be pressed into the top yoke

https://img.photobucket.com/albums/v619/baldgit/toptriplebushing.jpg

If I took all the bits to a machining/engineering place would they know what to do from looking at those diagrams?

I also need the stem pressed into the bottom yoke and a bearing pressed over the stem and the new bushing pressed into the top yoke.

Would anyone like to give a rough estimate of the price I'd be looking at? As a total noob to stuff like this I don't know whether I'm looking at a £20 job or a £200 job.

Thanks.

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

The biggest problem is those threads, they are such an odd size (23.82 diam ffs!). If your machine shops has a die then it is relatively easy but I guess they will need screw cutting on the lathe. Even then the guy will need a female thread to try them into (fork leg?).
Cost... at a guess two hours work, £100.
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..... · Quote Me Happy Joined: 15 Jan 2005 Karma :

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

$180 looks cheap IMHO, the bushes look straight forward enough to make.
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Bezzer · World Chat Champion Joined: 14 Apr 2005 Karma :

It isn't an odd thread size at all, it should be M24x1, being from a U.S. site they don't work much with metric and obviously don't realise a metric thread measures slightly under it's nominal size.
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Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

Right! so 25.83 is actualy 26mm. I still think $180 is a fair enough price
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Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Like Bezzer said, M24 tolerance is -0.05mm > -0.4mm. Mid point is -0.2mm which gives... 23.8mm.

I wouldn't think it would cost that much if you can get your hands on a CR stem, just some minor mods. The bushes are a few minutes work.
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