Halo Fix-G

Need to make sure wide base singlespeed cogs were used though as the thinner ones may be dodgy for fixie skidder types as they always left quite a mark on freehubs when I used thin cogs.
yep, and the splined freehub body really suffered if it was aluminium.

The Hal Fix-G hub features a fixed HG spline machined as part of the alloy main hub body
Doh!

I think it will last five minutes with a narrow (standard BMX) sprocket and a hoxton skidder.

Purely with all the reciprocating forces it will receive, not long before both sides of the splines are worn so bad the cog bites through and slips round (or strips/pushes off the lockring)
In any case, re-inventing the wheel again, nothing wrong with standard track hubs and cogs, HTFU