SL10 is aligned to the hexagon base on two edges, SL8 is aligned to two vertices.
Finally something that is truly MILDLY infuriating. Upvote!
My guess is the SL10 is wide enough that it needs the extra space available point to point, and as such is the only one that gets precision placement during machining.
I don’t think I’ve seen a how it’s made for driver bits. Would be interesting to know what special steps are needed.
Very manipulative post.
You make it look like SL10 would be great, and SL8 would be at fault. But you could also have placed the SL8 to be perfectly vertical, then things would not look that clear cut any more!
Justice for SL8!!!
It seems intentional that they are aligned differently so you can identify them?
This is an explanation I can live with.
No one refute it, please.

