Norm once talked about the "squares" method. Say your drawing is on a
1/4" square grid and you need to enlarge it 4 times. Draw a 1" square grid
and copy each mark from the drawing to the larger grid.
As for getting Sketchup to do it, you may have to draw the grid yourself.
And if Leon did it that way, what sort of curve did he use? As
It was an arc, a partial circle. After drawing the doors as if there
would be no arc then I added the continuous arc starting on either side
and extending to the opposite side. The line/ark was then pulled up to
a desired amount. All very easily done with Sketchup.
Print to scale, and there is a trick to that so ask one of us how to do
that. Simple to do when you know what has to be done. For larger
pieces like the center arc you simply continue to print to scale but
tape the pages together where the lines start and stop.
I think by definition the weight of the curve would come into play
however perhaps that would reverse the curve, lower in the center and
higher on the sides. I tried several variations including parts of an
ellipse and this seemed to look the best in this situation. Actually
looking at an angle the curve appears more elliptical.
Exactly! In Sketchup I drew the top unit and added an arc starting at
the bottom of the left door top rail and ended it at the bottom of the
right door top rail. Then in Sketchup I erased the parts of the ark
that were not actually touching cabinet parts. I then built the doors
and top center rail with no arc. I printed scale drawings of the arc's,
to glue to each piece, to guide me while cutting the arc's.
Maybe I'd use a
That's sort of what I would (do) do. The first thing I would do is decide
whether I want the doors to be conventional (as Leon did) or if I wanted the
door stiles to butt into the rails (which would give one continuous curve,
uninterrupted by the stiles. In the latter case, the tops of the stiles
also have to conform to the curve; harder but not insurmountable.
The second thing to do is determine the length of the board. If
conventional, one needs a board equal in length to the inside width of the
cabinet less the combined width of the stiles. Plus a fudge factor. If
non-conventional, the board needs to be the length of the inside width of
the cabinet. Plus a fudge factor.
The third thing is to make a template; plywood, hardboard, MDF are all
possibilities. I like 3/8" ply. To strike a fair curve on it, I generally
use a batten (thin piece of wood, maybe 1/8" x 3/4" x longer than the curve
will be) or a piece of 1/2" PVC pipe. Mark the batten/pipe at the center
and at each end where the curve ends will be, drive a couple of nails into
the template material where the ends of the curve will be, align the
batten/pipe at the ends and bend it from the center upwards against the
nails; when you have the curve you want, drive another nail into the
template material to hold it in place and draw the curve. If you are using
pipe, be sure to keep the pencil vertical. Cut out the template with band
or saber saw, clean up with plane and/or sanding.
When laying out/cutting the template, be sure to keep at least one square
edge so that it can be properly layed out on the finish board. If you layed
out the curve of the template relative to the edge that will remain straight
you can always use that to reference the template to the finish board; still
nice to have square edges though and they are absolutely necessary if the
finish board is to be curved at top and bottom and if one screws up and cuts
the curves before cutting the finish board into its various lengths. BTDT.
To cut the curve into the finish board, draw the curve from the template
onto it, cut out with band/saber saw leaving the line, tape template to
finish board and cut to template with router and pattern bit.
You asked about making the template half length and flopping it. I've done
it both ways but prefer making a full length one. IME, flopping it can
induce errors - especially at the center - if the alignment is off a bit.
If it should wind up a bit less than symmetrical side to side, that isn't a
catastrophe; unless it is gross, it won't affect joining and will never be
One other thing for your consideration is this: if the board that is going
to wind up as the top rails of the doors is wide enough, one could cut a
piece off the top of it to use as the top rail of the face frame. Also
depends on the look one wants and the grain pattern of the other pieces of
the face frame.
What sort of plane does one use to "clean up" the concave side of a
piece of stock? In case it's not clear, I don't mean this in a snarky
way; I'm not knowledgeable enough for that yet. :)
I mean, I'm guessing such special-purpose planes exist, but is there
something I'm missing here? Could such a thing be reasonably done with a
standard block plane?
Stanley #20 or Stanley #113 or record/kunz versions of same.
(Amazon.com product link shortened)
How well a block plane would work depends upon how much curve there is in
the wood and how the plane is held relative to the work; the closer it is
held at 90 degres to the work the less contact of the sole and the more it
will clean up.
A round or curved rasp works too. Ditto scrapers.
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