Originally Posted by
Kuromori
Is that a front or a stoker stem? I suspect you know this, but the reason for 7/8" is because the ID of the steerer is 7/8" to fit quill stems, and for these threadless-style stems a smooth piece of 7/8 OD tube was brazed into the steerer for it to camp onto, instead of clamping directly onto the steerer like a modern aheadset front end.
Yes, I was thinking as I rode home this evening that I probably wasn't clear enough on that. This is a front stem, for me because I'm too tall. I am making it before I make the stoker stem because I want to gain experience doing a simple copy before I go on to the more advanced work of making something from pictures.
Oh and in case anyone is wondering, the bars are 25.4 or 1". Standard French fare and a fairly available size in general, which is nice. The bars I have are probably pretty rare though. I haven't looked for a logo yet.
If it is a front stem, then also note that the bottom edge of the steerer side clamp tends to follow the line of the stem body instead of being perpendicular to the brazed in tube, since unlike an aheadset, there are no spacers to preload. It's one of those small details that lends to the elegance of the components and prevents from looking kinked or bent, unless that's just a reference plane to bore the steerer clamp hole.
Yeah, I needed a flat surface to drill into (and more importantly for reaming), and I was being generous when roughing with the bandsaw because I didn't want to regret it later. I can always shave more off. My original stem has the slightest bend to it, as you can see here.
Originally Posted by
ThermionicScott
Good stuff, @
scarlson. If you're interested, there's an article on making RH stems in BQ#17 (the tire issue). But since your stoker stem will clamp on both ends, I have no doubt you'll be able to figure it all out yourself.
I would like to know how they made the quill stems, and I may not have that issue. Given how easy this is going so far, I'm kind of inspired to make a quill one for my Ron Cooper, maybe incorporating a USB charger from the dynamo and a light switch. I think a compact USB plug and Buck converter would fit pretty nicely in a milled pocket in the side of the stem, if I shortened the slot a bit. Pot it in gray resin and it would be waterproof and look nice!
I have a hunch it's a taper, that's what my machinist friends tell me, to lock the quill to the horizontal portion.