A drilling machine for thin metal foils and flashing.
by Ralph Klimek Oct 2009
It
is often necessary to drill a larger hole in a small piece of flashing.
Lately I have had to do a lot of these for assorted projects and as you
well know, drilling a large hole in very thin metal does not work, and
if it does the hole is very ugly with torn edges. This simple
machine will even permit permit holes to be drilled into light gauge
copper flashing which as you know, copper sheet is extremely
difficult to drill or ream cleanly without tearing.
This
machine is made from heavy brass angle stock. It is longer than
absolutely required to permit simple mounting in a bench vise and give
good clearance to the drill bit as it will bite and plummet into
the air, not the vise.
I have tried make this tool with
aluminium , and allthough it works, aluminium is really too
soft. Brass better resists the sideways forces of the drill bit and
does not wear.
I have allowed for the most popular hole sizes,
including a massive 5/8ths drill because many of my RF projects require
this large hole for PL259 and type N connectors.
Construction
and usage should be self evident, allthough I will say it anyway!
To use this machine, the work piece is clamped between the brass
sections.
The brass sections are held true by a couple of 6MM
screws, tapped into the bottom piece. This has proven to be
sufficiently robust.
Contruction sequence first bind the two
brass sections, then, drill two 5MM holes for the attachment
screws and tap for 6MM. Attach and screw down the two elements. Only
then drill the desired work guiding holes. This will ensure
that the work holes are absolutely true. A drill press is
essential. Cheap n nasty Chinese made ones are now available for pocket
money prices and will last long enough to give good service to the home
workshop.
The tool can be used with a drill press or hand held drill.
