I have a Qualcast HTEG 55A corded hedge trimmer, , the blades spin, but do not cut the hedge.
I have removed the plastic cover at the base of the handle- cleaned out the grease and leaves etc.
What lubricant should be used for the gearing if any?
Likely if you've had it a few years the blades blunt, gears are metal and need grease use high melting point grease ask at garden centre or repair shop. May be you could get right type also from Halfords..