As per the title, I need a longer headset cap bolt, where should I get it from?
Also does it matter what it’s made from?
FWR Fasteners on ebay - it doesn't really matter what sort of steel it is (other than corrosion protection) as it's only used to pretension the bearing before the stem is clamped up
I've got loads in the bits box, if you're anywhere need the Tweed Valley pm me and you can pop round and try them, must be one which fits
Most are a standard M6 socket cap. Get a nice alu one of you like, it's not really taking much load. Stainless is also an option if you want to avoid it going rusty.
There are some oddball cap arrangements though.
Ok I need a countersunk 40mm bolt - so from whom should I get it?
Not near the tweed valley until October unfortunately, but thanks for the kind offer.
Given it's not load bearing I would go AliExpress or if you want it now Amazon (they have ti bolts )
Stainless headset bolts are pretty chonky, I bet a ti one can save you 5 or 6g 😉