With the ferrules done I could start working to mate them
to the wood handles. The first step is
to mount one of the roughed-out handle blanks in the scroll chuck centered on
the live tail center then turn the bottom half of the handle down fairly close.
With that done I marked the limit of the
dado cut where the ferrule will go.
Next, using a parting tool cut the dado deep enough so
the ferrule will fit snugly. The
difference between being too tight and too loose is measured in a few thousands
of an inch. I approach the depth very
carefully. You can always cut it a
little deeper but if you go too deep you cannot go back. The other thing is to make sure the cut into
the blank is square or very slightly back-cut.
Otherwise, the ferrule will not fit tight up against the cut edge. The top photo shows the finished cut and the
bottom is of the parting tool.
Here you can see how the ferrule fits on the blank. Each one is for a particular handle just in
case there is any variation in the interior diameter of the ferrules. Note the wood is a little proud of it. That way once I have the piece epoxied in
place I can come back and turn the wood down so there is a perfectly smooth transition
between the two.
Once all the ferrules are fitted I mixed up some two-part
black epoxy spread it on, twist the ferrules around to make sure there are no gaps
or voids in the epoxy bed then set them aside to cure overnight.
The next day the blanks are back in the lathe to
finish the transition between the wood and the copper ferrule. Here everything is ready for turning.
Using a gentle touch with the lathe tools I turn the wood
down until it matched the ferrule. In
addition, I also turned the end flush with the ferrule. Some finish sanding of the wood plus a little
light work with a file rounding over of the sharp edge of the ferrule and the
bottom half was pretty much done.
With that done I could work on the top half. To mount the blanks so I could turn them I
needed to use a simple fixture that is just a small cylinder with a hole
centered and counter sunk. This lets me
run a screw into the hole drilled in the blank to pull it up tight against the
fixture. Here are all the pieces ready to
be screwed together. There is a reason I
did not just mount the blank between centers and that will be obvious pretty
soon.
Once the blank is screwed onto the fixture I can clamp
the fixture into the scroll chuck and run the live center tail stock up to the
piece.
Next, I mark the finished length of the handle and
starting working the end down. Here I am
about half done.
Once I get pretty close to the finished shape I pencil
mark two lines near the end for a set of grooves. They are for decoration and to increase the
handle’s grip. Once marked I use an awl
to make a shallow reference cut then using the parting tool cut deeper. Last is to use hold some thin wire in the
groove while the lathe is on using the heat generated by friction to actually
burn the grooves. After the grooves are
burnt in I lightly sand with 400 grit paper to clean up any roughness generated
by the wire when burning. The pictures
below show the progression.
I can now finish turning the end down to where there is
only a small bit holding the waste next to the tail-stock on. A fine-tooth Japanese pull saw cuts the waste
off close to the end then I turn the remaining nub off, make the final shape
adjustments and do final sanding. Now you see why I could not mount the handle between centers. Here
is first one done with five to go.
Because they are going to be in a “set” I will need to take careful
measurements so they are matching.
After turning all of the handles, I finished them with
three coats of Danish Oil Finish. I used
this rather than my usual lacquer finish because these will be working tools
and I think that over time the handles will get a little beat up. If that happens I can clean the handles and
just give them another coat of oil. If I
used lacquer then re-finishing is a little more involved but still way less
than polyurethane. If they were a
presentation set then I would have considered lacquer.
I gave the oil on the handles about three days to cure
then buffed them with a cloth wheel loaded with carnauba wax.
Last is to mount the rifflers into the handles. The rifflers are manufactured in Italy so
naturally they are metric. The shafts
are about 3mm in diameter. My actual
measurement was .121” or just under 1/8”.
When I drilled a 1/8” hole in a test piece the riffler would not go in. The hole was too small. I double checked and the bit was 1/8” so it
should have fit or at least I should have been able to twist it in but no
way. I checked the hole with a digital
caliper and found that even though the bit was 1/8” the hole was about
.118”. The only thing I could think of
was there was some spring back from the wood fibers after the hole was
drilled. Going with this idea I ran
drill in and out of the hole several times which helped a little but not
enough. Going up 1/64” made the hole too
big. I could have epoxied the rifflers
in the handle but wanted to be able to remove them if the situation called for
it. What I needed to do was to ream the
hole out or compress the fibers just a smidge.
To do that I took a 16-penny galvanized nail put it in the lathe and filed
it down to .122”. The photos below show
the before and after of that process.
To use my custom “reamer” I started the lathe then by
hand ran the handle in and out on the nail.
That helped. I think it burnished
the wood fibers but not quite enough.
What did work was to use the heat generated by the friction of the nail
spinning in the hole to melt a little wax on the nail then run it in and
out. I don’t know if it was the wax that
added a little lubrication or if it held the compressed wood fibers in place
but it worked. Here is the finished
product, six rifflers mounted in matching cherry handles.
Next Up – Case Plans & Roughing out Blanks
No comments:
Post a Comment