On 2/2/2019 4:29 PM, DerbyDad03 wrote:
On Saturday, February 2, 2019 at 4:31:15 PM UTC-5, dpb wrote:
On 2/2/2019 1:44 PM, DerbyDad03 wrote:
...
I can set it all up again, shim the board and post another picture or you
guys can trust me when I say it's shimmed correctly so that all movement
is prevented. As I mentioned to dpb, every board needs to be shimmed
differently, so even if I posted a picture of *that* shimmed board, you'd
have no way of knowing of I shimmed *every* board correctly. You're just
going to have to trust me...or not.
Other way 'round ... not that we don't "trust"; you came asking for help
and from afar, _seeeing_ pictures of how you had the set up when you
actually tried to make a trial run is the only way we can see if
something shows up to us that didn't to you.
Your choice of how far to try to push the long-distance diagnostics but
the clearly obvious seems to have mostly been eliminated (other than the
very first basic test I suggested to prove the planer itself is doing
what it's supposed to).
Remember, too, you're looking for minute details...a few thou here and a
few thou there can add up to real... 
All true, no argument.
As far as "the planer doing what it is supposed to do" I have another 'test'
question, as in "should it be doing this".
I was doing some basic thickness planing today. Assume a board that was
already flat. 8/4 x 3.5" x 26", S2S.
I need to get it down to 1.5" thickness. I sneak up on the cut, half a
handle turn at a time (should be 1/32") Eventually the rollers grab the
board and pull it through without actually cutting anything. Another half
turn and I hear a full length planing sound. So far so good.
The question: If I pass the board through again, *without turning the handle*,
should I hear a full length planing sound? If I then pass it through again,
*without turning the handle*, should I once again hear a full length planing
sound?
I have found that I can pass the board through at least 3 times and still
hear it cutting. The sound is a little quieter each time, but there's no
doubt that it's more than just the rollers pulling it through.
Since it's a narrow board, I tried passing it through the middle, the left
and the right to see if it made any difference, but as far as I can tell, it
doesn't.
Should it be making a planing sound on up to 3 passes even when the head
has not been lowered?
That's a sign of what I've been thinking has to be with the little
planers; even in the big boys like the PM 180 there is _some_ mechanical
play in the various pieces in the planer itself; from the lash in the
height adjusting mechanism to the yield of the bed and head supports
plus what small compression there is in the workpiece itself as it goes
through. All of these effects add up; they're normal and basically
unavoidable no matter what the machine, only how much is dependent on
just how well-built and stiff the machine itself is constructed.
Do you have precise-enough calipers to measure the difference in
material thickness between such passes? For "ordinary" woodworking, it
would be within normal tolerances so it really isn't anything of a deal,
whether with your particular machine and the off-center work it
contributes, I really don't see that effect being the one that would
cause the end effect that you seem to be experiencing.
In short, it's normal to an extent, a second pass on the PM180 is
essentially knife-clearance except for a knot or somesuch. Of course,
it weighs 1670 lb, too...
--dpb