I would, but this isn't the first time I have noticed this. It has happened
with maple and cherry as well. I just thought I would finally post and see
if I am the only one that has experienced this, AND it looks like I am not
alone (see Rick above).
Beautiful work! Your website is elegantly done (the photographs of your work
are stunning), and your "What I Believe" statement is reflected in
everything you see therein.
All in all, visiting your site and seeing your work is an inspirational
experience, providing food for thought for every serious woodworker. Thanks
for the sharing!
Here's my take:
I believe it is an issue of differential compression -
Suppose we have a block that measures 2"x2"x2", and try to
The block will compress less when the force is applied to
the end grain.
I suspect that then you are cutting the end grain mortise,
the forces of each cut (yes, they are happening fast, but
they are really a series of individual cuts) compresses the
stock more than when cutting into the cross grain. After
each cut, and the compression it causes, the wood springs
back to its original position. Because of that differential,
the end grain mortise is smaller than the cross grain
mortise, even though they are cut with the same setup.
These things are hard to describe. I hope that what I've
written makes some sense.
All the best,
*SNIP* of interesting mechanical hypothesis
That could could have some validity, except that those using the Multi-
router find that to be untrue. Same exact approach to the application
except the difference in the jig. If they don't squeeze up on the
Multi-router (read: tank-like jig) then I am thinking as mentioned
above it could actually have to do with the cutting itself.
It isn't a hard stretch to think that (especially a mortise cut with a
router) would deflect away from one side or another. And if you clean
up the middle as you go, the bit might lean a thousandth or two
towards the empty area, away from the solid sides. Remember, if it
only leaned ONE thousandth in on each side, that would make it two
thousandths in aggregate, and that would make a really snug fit.
My thoughts exactly... Kenneth beat me to the punch.
I think that the longitudinal wood fibers are "compressing" slightly as the
cutter makes a "shearing" cut along the same axis as the grain.
One way to test this theory would be to make both the end grain and cross
grain cuts and then measure the mortises with a dial caliper. I wouldn't be
surprised if the difference is more than a few thousands... and that would
confirm this theory.
The remedy I favour is a swipe or two with a sharp shoulder plane. Veritas
makes a nice one:
Message posted via CraftKB.com
As long as you're testing this, test it with a straight cutter vs a sprial
cutter (OP stated he was using a spiral cutter). I would think that the
compression, if present, would be worse with the straight cutter.
my $.02, ymmv, etc....
The point I was thinking of when bringing up that particular jig is
that it holds the router in a perfect position, rock solid, and
creates a near perfect cut.
Since the only voice we have heard from that indicates no difference
in the fit from end cuts to face cuts when using that particular jig,
I suspect that the jig may have something to do with it.
In the end, I don't really know. It is too easy to run the tenon over
the belt sander for a great fit.
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