Flattening the Stanley #6 Shooting Plane

A couple weeks ago I noticed that my #6 that I use as a shooting board plane was not exactly flat on the sole.  Holding a straightedge across the bottom revealed quite a gap.  I didn't measure the gap at the time, but when I sharpen the plane and made test cuts on the edge of a 1/2" thick board I got a much thicker shaving in the middle of the plane than at the sides.

To start the job, I made sharpie marks across the sole and got out my plate glass reference surfaces that have sandpaper glued on.  Eighty grit on one plate and 180 grit on another.

A few minutes on sandpaper reveal the low (darker) areas

After a little time on the 80 grit paper that sheet was worn out and I had no more paper in that grit.  So I went to the 180 grit and went through a few sheets over the next half hour.  Most of the sharpie marks were gone, but more importantly I got a nice flat surface around the mouth.  Here is a photo of the sole of the plane looking from the heel to a straightedge laying across the sole about an inch ahead of the mouth.  Just the slightest hint of light.

Looking down the sole - very little light coming through

I have a set of feeler gauges that I bought many years ago from an auto parts supplier.

Cheapie set of feeler gauges

The smallest gauge in the set says 0.0015" on it, so I tried to fit it under the straightedge to measure the gap in the previous photo.

0.0015" (or 0.038 mm) gauge

It didn't fit in the gap, but I thought something was not right so I measured the gauge.

WTF??!!  0.0060" !!

You know what Belushi said to Flounder in the movie "Animal House"  -  "Face it Flounder, you f---ed up.  You trusted us."  Maybe I won't trust these gauges again without verifying them first.  Well, the next larger gauge was 0.003" and I verified it.  It didn't fit in the gap and I'm comfortable that 0.0015" also wouldn't fit.  Maybe 0.001" would fit, but I'm OK with that.

After having flattened the sole, I tested it on the edge of a half inch board and got consistent shavings all across the sole - left, center and right.  Then the obligatory test cut using the shooting board got nice shavings (with freshly sharpened blade) in cherry.

Fluffy end-grain shaving

One problem, though.  The end grain did not come out square to the reference edge.  I had to shim the work piece in the shooting board to get it to square.

See the paper shim (double thickness) between the work piece and fence?

Arrgh!  It's always something ...

EDIT, Added 06-May-2016

Ralph of the "Accidental Woodworker" blog suggested in the comments below that my shooting board fence might not be square to the plane sliding track.  Well it didn't take long to find out he was right.

Checking the shooting board fence for 90°

A closer picture shows the gap on the right.

Tiny gap on the right side, none on left

It's hard to imaging how this could be since the fence sits in a dado that was created with one wall square to the track.  But wood moves and compresses.  The fence is made from poplar and the rest of the board from pine - both very soft woods.

So I tried a couple of things.  First, I checked the 90° wall of the dado.  It didn't seem perfect, so I knifed another line about 1/2 mm away and chiseled a new wall.  When the fence was re-installed, it was still not square to the track.  That meant that the fence had to be adjusted.  So for my second idea, I shaved off a little from each side of the fence and re-fit it to the dado.  At first I took full length shavings from both edges, thinking that I shouldn't change the angle of the wedge-shaped fence.  The shavings showed where the fence had compressed against the dado walls, but the problem persisted.  So I shaved a little more off the left side of the fence, primarily the part that extends past the base of the shooting board.  I was concerned that the fence wouldn't match the angle of the dado now, but this worked and the board is now shooting squarely again.  No pictures, unfortunately.