Rather than try to file an oval, it
occurred to me that drilling at an angle will do the trick easily

Make sure to use a drill bushing regardless of the tool you eventually
choose. It'll keep that drill from wandering "downhill" or off your
intended mark. If tolerances are not too critical, you might be able to get
away with not using one... And if teh holes are large enough.
--


Regards,
Joe Agro, Jr.
http://www.autodrill.com
http://www.multi-spindle-heads.com

V8013

On Sat, 11 Dec 2004 19:41:31 -0600, Australopithecus scobis wrote:

Greetings,
I'm starting a project to make some moulding planes from scratch. A
hollow plane requires an oval cutting edge, to account for the bedding
angle of the blade. Rather than try to file an oval, it occurred to me
that drilling at an angle will do the trick easily. Now, how to do it. I
have available a benchtop drill press and lots of clamps. I'll probably be
using 1/8" O1 for the blades. My plan is to drill an undersize hole
straight through, then jig up the blade and re-drill with the final size
bit. The undersize hole should give the larger bit a place to bite. Is
this an approach that will work, O wise metalworkers?

I'll still have to grind and file the matching rounds, of course.

While it might seem a difficult task, in 1/8" O1 in the soft state rough
grinding and filing to shape goes surprising fast. I usually hog out the
waste with a small angle grinder, use files to come up to the line and,
if necessary, finish out with Dremel or die grinder. Then harden/temper
the iron and sharpen.

--
The instructions said to use Windows 98 or better, so I installed RedHat.

It is possible to layout the distorted shape by hand. At some
point, you might want to get yourself a copy of the knifegrinding (as
in moulder and wood shaper knifegrinding) manual from Charles G. G.
Schmidt in Montvale, N.J. As I remember there's a pretty good chart in
there that will show you how to distort your profile so that it cuts
what you actually want. The principals are the same. Profile grinding
machines take care of this by simply grinding the knife blanks already
mounted at an angle in their cutting heads. Then the task becomes one
of simply following a pattern with a stylus, just like reproducing a
key in a hardware store.

Charles Morrill