I was going to mount the STIHL FixCut 25-2 head on my trimmer, but found out that there was not a Mounting Nut in the package. Since some of you may lose these from time to time, or know what size nut (thread? sae or metric?). Would you let me know, so I may run down to ACE tomorrow and get a nut. There is no Dealer/Repair in town, so I have a problem. Maybe I can call the nearest dealer tomorrow. Anyhow, you might let me know. THANKS!