Yesterday was headset day, I'm still not entirely sure why I bother, no-one notices a headset (unless it doesn't work), and they're easily available to buy.
So why the DIY approach? Well I reckon my time is pretty much worthless, quality headsets are expensive, and if using you're using some fork brands on custom frames, the headsets just don't fit properly. They leave a big gap above the fork crown, or if using 1 1/4" tapered steerers there is limited availability, Chris King make the Inset 8 for mega-bucks, people do use Hope 1.5" headsets and custom build a bearing seat to fit. The latter looks ugly and is a bit of a bodge.
What do I do then? First buy a pair of quality stainless bearings, this alone sets you back more than a cheap off the shelf headset. Then I set to and make the bearing cups. I'm sure the likes of Hope can churn these out in a few minutes but it takes me a solid day, and given my tendency to make numerous mistakes, often a couple of days.
I'll outline the process:
-Take a large bar of good aluminium (careful - if the quality is shoddy it won't anodise well).
-Spend all morning getting the band-saw to cut straight as it's been wayward for at least a year.
-Cut a suitable chunk off, mount up in lathe and set too.
-Rough it out, then measure, measure and measure again, the bearing should be a nice snug fit, although location is accounted for by the 45 degree shoulder on the bearing and in the headset cup.
-Have loads of fun getting the shape "just right", Chris King curves or Hope edges, curves all the way IMO.
-Make sure the interference press fit for the frame is just right, botch this and you'll have to start all over again, been there, done that, got the tee-shirt(s).
-Polish out all marks from shoddy machining operations.
-Clean thoroughly and don't touch without gloves before anodising.
-Anodise in the super sophisticated (see photos) anodising tank.
-Apply stencils, in the absence of a laser engraving system this is the next best thing, but it's monumentally fiddly to get right. Repeat until they're either straight, or you're so fed up you no longer care.
-Pop into the dye and cross fingers. Due to the shonky DIY anodising system this always ends up being a matter of luck, I've failed to achieve consistency here. The reasons for lack of consistency are probably/possibly a failure to calculate anodising time wrt surface area, poor control of voltage, poor control of temperature, poor control of electrical contact, poor control of sulphuric acid strength. In summary poor control of everything and also "unknown unknowns".
-Repeat as many times as is necessary to get a decent result, by stripping anodising off with a caustic soda solution and starting again.
-Polish carefully on the buffer with a loose mop and jeweller rouge or similar.
By the way, get a very good quality bung for the steerer, ideally it should support all of the clamping pressure from the stem, Columbus sell a good one. If it's too short, or positioned badly the stem will compress the unsupported carbon steerer, which will then delaminate and you'll have to junk a pair of expensive forks. The Cannondale steerer/top cap bung is probably the best example of how not to do it.
Final stage: Fit to bike, admire, realise no-one will notice or care, pretend it was easy.
WARNING
Don't try this at home without a great deal of care, electricity, acids, alkalis, noxious fumes and nasty stuff all round, or do try, but don't blame me.
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