I assumed the as cast LM4 while being a bit goey would be wonderfull for rollforming threads, which wasn't the case however this batch of castings are LM25 TF, what a differance, all the machining is better, the roll formed threads are so differant, you would belive it was the same process, they have plenty of depth and look nice. I drilled the holes a tenth[mm] small, which makes them very tight, the studs fit beutifuly.
they are so nice I now have to buy roll taps for all the other holes in the casting.
The cost was an extra £5 on a 50 quid casting, I didn't ask how much extra was the heat treatment and the LM25 individualy?
-- richard