Evening All

I need to drill some new holes in 2 hubs to accept Cortina style splined studs. If I measure over the new splines with a vernier 14 mm dead what size do I make the hole? Obviously it needs to be a bit smaller to let the splines bite into the hub. I'm thinking 0.5mm smaller = 13.5 mm? The hub is cast steel.

I've also got some aluminium hubs to work on, I would think you need a bit smaller in ally, maybe - 1mm?

Cheers

Fred W B

I made some holes for some 13.3 mm studs - I made a 13 mm hole as 13.1 or 13.2 drill bits are v expensive. It worked, barely, but I think this is too tight. Snapped a vice and could barely press them in, occasionally I worry I've over-stressed the hub (doubt it though).

When I researched this I seem to recall finding that 0.15 mm difference was about ideal. So I would go for 13.85 if possible, or 13.9 if not. (You might be lucky and get an imperial size that is a good match).