These are for my concrete speaker bases.
Threaded rod same diameter as you inserts ( these are 6mm ).
I cut these into 4 cm lengths leaving a nut on before the cut to fix the thread.
A bit of masking tape around half the rod to prevent damage and insert into a variable speed drill.
Make a template to get a suitable angle to the side of a grinding wheel and spin the drill in the opposite direction to the wheel and you end up with a pretty good spike.
Threaded rod same diameter as you inserts ( these are 6mm ).
I cut these into 4 cm lengths leaving a nut on before the cut to fix the thread.
A bit of masking tape around half the rod to prevent damage and insert into a variable speed drill.
Make a template to get a suitable angle to the side of a grinding wheel and spin the drill in the opposite direction to the wheel and you end up with a pretty good spike.
