I changed the disc springs to be in 3's instead of pairs but as I suspected the travel was too short and it wouldnt grip the pull stud. I stripped it down again and removed half of the discs and put them back to pairs and this time there was enough travel to grip but its just on the edge for releasing. I will keep an eye on it but so far all holders I have release ok. Anyway I shoved the force gauge in and it was now reading 2000 PSI so thats 666.666 lb-f, so was quite a bit better but still lower than I was thinking it should be. I had tried to get info on what it should have been from a few more sources but no one knew, then out of the blue I got a phone call from Chiron. The guy didnt know what the force should be on my machine but he said that the 40 taper machines of the vintage of mine had a force of 4.5kn, that works out at 1000lb-f approx.
I looked up the PDF I had found earlier with usual forces and divided the 4.5kn into the 10.23kn that it said for a 40 taper, I then divided what it said for a 30 by that result and lo and behold the number that popped up was 527lb-f just around what I got when I replaced the discs. So now I am wondering if I should keep it at the higher value or put it back to pairs again, decisions decisions
Hood