Swingman wrote in
:

On 3/8/2013 8:39 AM, Mike Marlow wrote:
Swingman wrote:
On 3/7/2013 1:25 PM, Mike M wrote:

I had to look at that drawing a bit to grasp how much that 1/16"
caused the measurement to change. The sketch up is definitely
something I'm slowly learning.

Being an ex-artilleryman I'm not a stranger to angular deviation,
but I was struck by the magnitude of this particular situation
myself.

Likewise (although not with the artillery background), I am familar
with the fact that the deviations will result in greater deviations
over distance, but I too was surprised at what such a seeminly small
tweak resulted in with your chair.

It makes sense when you think about it. Visualize this:

Rotate a vertical line, 40 1/4" high (which is roughly the height of
the center point of the curved chair leg), 1.4 degrees around a point
16 13/16" (the height of the top of a side apron) from the bottom of
the line.

That rotation moves the top and bottom points of the line just shy of
1" away from each other on the vertical plane (13/32" on the bottom,
and 19/32" on the top +/-).

Being aware of that is what got me to checking ... (I was really
looking for a way around routing mortises on the edge a compound
angled apron).

Although the Multi-Router makes that operation a piece of cake, the
fact of mirror images and references edges with grain direction being
involved, made mistakes inevitable ... and this job has a razor thin
margin for material costs.

Another option would have been to angle the face of the leg at the
mating point appropriately, but that causes just as many consequences
that needed to be guarded against.

Oh well, all's well that ends well ...

Yes, that is also the way leverage works. I think you're making great
reproductions now (not like the watches on the streets of NY at all!!
smirk). I even understand the angling on the face of the leg ...

Great work, annd great explanations, as usual!!

--
Best regards
Han
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