Problems with LoSpec brakes leaking

[chrisj]

I've had some billet 4 pot calipers on my car for a while now, but due to a variety of reasons they have only covered about 300 miles.
I've already had to replace one leaking piston seal in the drivers side caliper (caused by swarf and chips of ally left over from machining....) but since putting the caliper back on the car and bleeding the system, the outermost bleed nipple on the same caliper won't seal.
We've tried tightening it to varying degrees up to about as tight as we dare but it still leaks.
I have a spare caliper (that would be the first drivers side one they sent where they 'forgot' to drill out the internal fluid passages....) so I had a good look at the bleed nipples on that and noticed that the finish on the taper was pretty rough.
Maybe this was tearing the ally when it was tightened so no seal could be created?
I tried cleaning down the end of one of the spare nipples hoping that a smooth finish would sort the problem.
Tried that last night and no change.

So, has anyone else had the same problem?
When I asked LoSpec they said they had a batch of nipples a while back where the taper was too pointy, so I should 'grind a bit off the end as that's what we do'.

Any help or suggestions would be greatly appreciated, I daren't drive the car when the brakes are like this, and if it's not sorted they'll be going in the bin to be replaced by Wilwood Midilites.