Correct
screwdrivers can be found in one of two ways, depending on
the
size you need. For the small sizes, get
watchmaker screwdrivers.
For
larger sizes, get gunsmith screwdrivers. Both
have hardened tips,
hollow ground so the point that fits in the slot of the screw has
parallel sides, not tapered sides. With those you can work those
screws
without damaging them, even if they are quite
tight.
Another way to find larger HG sizes is to get a (good) set of power-
drive bits that will fit a screwdriver socket handle. Although this
has its problems with getting into tight spaces, sets of hollow-
ground hardened power bits are comparatively easy to find.
Good point. However, those (and hardware store flat bits in general)
come only in a few sizes. You get a choice of width but not (as far as
I have seen) a choice of thickness. By contrast, a decent gunsmith
screwdriver set has a lot more widths, so you can more closely match the
screw diameter, and it will also offer a given width in 3 to 6
thicknesses, so you can find the bit that is a nice snug fit for the
screw head you're working on.
It may be that slotted screws are well enough standardized that this is
overkill, but I suspect not. Certainly not in guns, where the
nonstandard is usual. :-)
paul