In uk.rec.gardening Chris J Dixon wrote:

Further investigation is currently blocked, as one of the screws
in the top moulding, which is the first step to dismantling the
machine, has a one way head, looking rather like this:

http://www.alliedboltinc.com/product/10-24-X-1-inch-ONE-WAY-R/H-MACHINE-SCREW-STAINLESS~2263.aspx

and it fits in a recess.

I have seen rather expensive removal tools, with a couple of
pins, but the reviews are, at best, mixed.

The simplest, and crudest, solution is the attack the screw head
with a Dremel cutting disk, and attempt to cut a sharp enough
edge to engage a screwdriver. This will inevitably cause damage
to the surrounding plastic.


If the screw is close to an edge you may be able to Dremel through the shank
along the join-line.

If you have [access to] a mill and the part is sufficiently robust you can
mill the top off the bolt.

If you have a drill press you might try putting a pair of holes in the
flats and making a pin-tool from a screw-driver (though the "like-this"
part you link to is stainless and hence likely to be tricky to drill).

Extremely unlikely is a through-hole - but if so you could drill through
from the other end; often this will make the screw unscrew.

Tools that won't come apart are for girls.