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Post by greenbat on Oct 8, 2015 22:11:58 GMT
Morning all. Apologies for a non modelling question, but it is machining related and I reckon this is a good place to find knowledgable people.
I've been asked to make a new steering stem for some motorcycle fork yokes, for someone who is building a special. What would be a good steel grade? I reckon EN16T, being toughened high tensile, but want to be certain before I do anything. It would be most embarrassing if the bit I made makes the front fall off!
(For anyone interested, bloke is fitting some modern ZXR forks to a mid 70's Kawasaki KH500 triple.)
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Post by Doug on Oct 9, 2015 6:38:45 GMT
Morning all. Apologies for a non modelling question, but it is machining related and I reckon this is a good place to find knowledgable people. I've been asked to make a new steering stem for some motorcycle fork yokes, for someone who is building a special. What would be a good steel grade? I reckon EN16T, being toughened high tensile, but want to be certain before I do anything. It would be most embarrassing if the bit I made makes the front fall off! (For anyone interested, bloke is fitting some modern ZXR forks to a mid 70's Kawasaki KH500 triple.) this is quite a well traveled path, i myself looked into fitting R6 forks into an FZR oddly the stem tube is normally replaced by threaded rod holding the two parts of the tripple tree together i always thought this a bit bodgy so a stem using EN16T would be very good indeed with either a fine thread 20mm top and bottom or some large high tensile cap screws M14 size. i personally would go for a M20 fine thread and nuts as its easier to get the tension correct on the stem bearings. all the best Doug |
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Post by gwr14xx on Oct 9, 2015 6:55:17 GMT
Hi, It will depend on what material the bottom yoke is made of, and how the stem is fitted. If the stem is welded into the bottom yoke, you will need to use a material that is compatible and not result in brittleness around the weld. If the stem is just clamped in, then EN8 or EN16 should be fine.
Regards, Eddie. |
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Post by andyhigham on Oct 9, 2015 11:25:27 GMT
The majority of modern sports bikes use aluminium for the stem.
If you think about the forces involved, the only forces applied to the stem are at the point where the bearing meets the yoke, there will be a shearing force here. there will also be a (slight) tension force along the axis of the stem caused by the bearing pre-load
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Post by greenbat on Oct 9, 2015 22:13:15 GMT
oddly the stem tube is normally replaced by threaded rod holding the two parts of the tripple tree together Urrrgh!   I'll go with EN16T then, found you can get a metre of it posted for £30. Gives me 3 attempts at mucking it up. Thanks for your help |
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