andybeau said:
If you have not already done so I suggest trying to find some suitable hex bolts and nuts to mount the OC9 firmly in the headshell, the OC9 body is pretty deep and if I recall correctly you need 19mm bolts to do the job properly.
Comventional screws and nuts are not tight enough, they easily work lose and this has an unpleasant effect on SQ.
Ideally you should use tweezers to fit cartridge tags, needle nose plyers are fine if they are small enough but do make sure the tags are a tight fit on the pins.
Don't know why you would think this, cap hd screw, philips hd screw,etc will tighten the same as a hex screw/bolt
def of bolt thread length 1.5 times dia
def screw threaded all the way to head
All bolts/screws will loosen over time unless you use spring washers or nyloc nuts or thread lock
Really not sure what you are getting at Andy unless it is that I am not being precise enough on my classification of bolts and nuts.
I have never found conventional screws of sufficient quality to mount m/c cartridges firmly, the screw heads are to soft and easily damaged and have to be fitted from the top making it extremely difficult to hold the nut securely enough to get a tight fit. This is a practical matter, not a matter of engineering specification.
The use of hex bolts, fitted from underneath and secured by a nut that can be firmly held in place by a suitable spanner is, in my experience mandatory for metal body m/c cartriges. The vibration generated by low compliance cartridges of this type will work lose an inadequately tightened scew/bolt in a mater of weeks, properly tightened hex bolts can stay tight for years.