> Doug Dawson wrote:
>  
>    It seems like you can, i.e. that's what people are measuring,
>    more or less, _provided_ you apply the requisite amount of
>    downward pressure, which was ten pounds in that case.  I chose
>    that figure, because I kind of doubt that people would ever be
>    applying _more_ than that, _downwards_, during normal planing.
>    Remembering that we're usually applying force to the plane
>    during planing, in a downwards/forwards direction, the
>    downwards force will typically ( methinks ) be no more than
>    half the total applied force.  Think of pushing a 30 pound
>    weight around for some length of time...  It's semi-clear to
>    me that that's the upper limit of what we'd be willing to
>    tolerate for an supposedly functioning plane.  But I could be
>    wrong!  I.e., I don't have the measuring apparatus to determine
>    how much force I'm applying to a plane in use.  Anybody willing
>    to do some experiments on this, by all means we'd be grateful
>    for you're help.

I was using a little hand held force gage just yesterday at work.  I
playing with a prototype fixture I'd built for a hand assembly line and
had borrowed it from one of the Industrial Engineers to check the
ergonomics.  Turns out it takes about 12.5 lbs to insert the part in
my fixture, so at the moment I have a good feel for what 12.5 lbs feels like.
It ain't much.  Based on my experiments yesterday with this device I 
wouldn't be the least bit surprised if the downward component of planing
was at least ten pounds.  In fact, some of the beefier galoots probably
have hands that weigh more than 10 lbs.  :-)

Keep in mind that all these theoretical calculations don't amount to
anything if the plane isn't concave.  All bets are off if the plane is
flat and is supported by the wood along it's entire length.  (Sheesh,
next thing you know I'll be blowing the dust off my Timenshenko strength
of materials book).

It's a fun discussion, but if I wanted my tabletops to be planed flat within
0.001" I wouldn't have gotten into oldtools.  :-)

-- 
Scott Post   spost@n...
Just say we're exceeding the anal retentive stage here...