Basically you cant!!
We had a perfectly good JCB Petrol strimmer which is now in the skip! The spool bolt started to spin and could not be removed.
Apparently the story is this!
When JCB went into liquidation, a Company bought the name and as far as I know imported a load of Strimmers and badged them JCB, but failed to get any spare parts!
Our local Garden Centre in Devizes has 4 of these (and McCulloch) in their workshops for 6 months now!
The problem is the parts are not interchangeable with any other make!
Paul, May 2009