A long time ago when I was in high school probably in
1968, I got a chance to use a hand router plane. It’s a non-powered hand tool made out of
ductile iron that uses various sized bits to clean out and flatten the bottoms
of dado and rabbit cuts. I remember
being impressed with how easy and handy it was to use. Here is what a modern version of the tool
looks like.
I had wanted one for a lot of years but a good one is
pretty expensive for a niche use tool.
However, recently I came across a set of plans in Woodsmith® magazine
#246 for making a wood bodied one. After
putting a couple of the blades on my Christmas wish list my son got me a
pair. One is a ¼” wide blade and the other
is a ½” spear point. Here is what they
look like.
Having the blades in hand I went to SketchUp to draw up working drawings using the Woodsmith plans as a starting point. At this point I have made just a couple of
changes. First, is adding a half an inch
to both the width and length of the body.
Second, is to change the handles from a simple ball to a little more
ergonomic style of handle. Here are
above and below renderings of the plan.
Typically, one would have a single router plane and
switch the blades as needed depending on the required function. That was my original intent but then I got to
thinking as long as I am making one it’s not going to be that much more work to
make two. That’s because the amount of
time thinking how to proceed, measuring, setting up the equipment and testing
is probably more than doing the actual machining.
Selecting wood is next on the list. It gets down into the mid 20’s here in New
Mexico in the winter and since my shop is mostly unheated the lows in there at
night dip into the mid 50’s before heating up in the afternoon to the mid
60’s. When I got out to the shop there
to my surprise was a lizard sunning himself in the light coming through the
south window trying to keep warm.
Anyway, back to the wood selection. For the plane body I selected cherry (Prunus
serotina) because it’s stable, machines well and I really like it. A second wood is needed for the wearing
surface of the base. It needs to a hard
and durable wood to resist the wear and tear it will be subjected to. In my on-hand supply of material there are a
few candidates. Katalox (Swartzia cubensis), Gaboon Ebony (Diospyros crassiflora), Honey Mesquite
(Prospois glandulosa) and Texas Ebony (Ebenopsis ebano). However, as I have a very limited quantity of the Katalox and the Ebony both were eliminated from consideration. The next bit is for the wood nerds and
engineers out there. For reference I did leave the Katalox and the Ebony in.
There are a couple of indicators for wearability:
- Specific gravity (SpG) or how dense the wood is. SpG is measured as the ratio of a wood’s density compared to water. A wood the same density as water has a specific gravity of 1.00. Less than 1 and it floats more than one and it sinks. The denser a wood generally the higher the wearability.
- Janka Hardness This is the amount of pounds required to imbed a .444″ diameter steel ball into the wood to half the ball’s diameter when the wood has been dried to a 12% moisture content. This number is very useful in directly determining how well a wood will withstand dents, dings, and wear.
Wood SpG Janka
Cherry .56 950 lbs.
Mesquite .82 2,340 lbs.
Texas Ebony .97 2,820 lbs.
Katalox 1.05 3,660 lbs.
Ebony .89 3,080 lbs
As you can see from the above information both the
Mesquite and Texas Ebony are way better choices for a base than cherry and not
all that different from each other. It
is interesting that Texas Ebony with a specific gravity of .97 will barely
float.
My piece of Mesquite is half a log that was probably cut
7 or 8 years ago. The Texas Ebony has
been drying for at least 15 years and still had a lot of sapwood on it. In the photo below the Mesquite log is on the
bottom and the Texas Ebony pieces are on the top. The piece of the Texas Ebony under the plane is how it
started and the front piece is after I flattened it with the hand plane and ran
it through the thickness sander. I
decided to work both pieces down to finish usable material and see what I ended
up with as both pieces have some splits and cracks.
After using the hand plane to give me a straight edge I
used the band saw to slab off pieces of Mesquite a little over an inch thick.
Here are the slabs.
Three are an inch thick while the back one is about 2 ½” thick.
The same process is used with one of the Texas Ebony
pieces giving me the two slabs here. If
you look closely you can see the knots and some of the cracks I will need to
work around. I did not cut up the other
billet of the Texas Ebony but will hold it in reserve.
After a lot of measuring I decided to use the Texas Ebony
for the wearing base and will put the Mesquite back in storage for something
else. Once all the split ends and bad
spots are cut away here is the 4-piece glue-up I will use to build the wearing
base blank. The white triangle is used
to align the pieces so when glued up they will get put together in the correct
order and alignment.
Here is the glued and clamped up base. The two large red clamps keep all the pieces
aligned so the edges match up and are in the same plane. The two horizontal orange clamps plus the
gray one provides the clamping force for the glue joints themselves.
After an overnight cure the clamps are removed the blank
is run through the thickness sander with 100 grit paper to smooth and
flatten. That’s followed by a very light
trim of the long edges on the table saw to make sure they are parallel to each
other. With that done I rough laid out
the base shape with a paper cutout working around the flaws in the wood. The ends are then trimmed up so they are
square and the blank is a little long.
Marking the blank for ripping in half on the bandsaw to get two bottom
wear plates is next. If you look close
at the bottom edge you can see them as a very faint set of centered white
parallel lines. The bottom image shows a
closeup.
Next Up – Templates, Flattening Blanks & Hardware
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