The Handle
We use the
telescoping metal handle from a floor duster for our net handles. The
handle from the
Hero™
floor
duster, from Canadian Tire™ (part no. 42-9372-0, $14.99), works
well
(Photo 1). It
collapses from 47.25 down to 26.5 inches. The assembled net is
less than 42 inches long when collapsed and fits very nicely in
the back seat of a car. At the mop end of the handle, the outside
diameter is 0.76 inches and the inside diameter is 0.72 inches.
NOTE: The CTC™ web site does not show this mop with a telescoping
handle, although it came with one in January 2010. I have recently seen
a different style of
telescoping
handle at Princess Auto™. It is very reasonably priced (~ $4). I
have no
way of knowing if it is suitable. The handle diameter will probably be
different as well, so you'll have to modify the diameter of the plug to
fit into it.
UPDATE: I acquired one of the handles mentioned above from Princess
Auto™ and they work quite well. The inside diameter is about 13/16
inches, so 3/4 inch dowelling will not be big enough for the plug. They
are about a foot longer than the mop handle we have been using, which I
think is a good thing. They were selling for $2.99, which makes them
even more appealing.
Photo 1 - The Duster
The action of a telescoping handle should be tested before you buy
one.
Extend and retract it several times, locking and unlocking it at each
extreme. If it fails to lock at either end, and a few will, try a
different one.
Remove the mop head from
the handle by depressing the button on the plastic end fitting of the
handle. The handle end fitting is made
of plastic (Photo 2) and can be cut off with a hacksaw (Photo 3).
Photo 2 - Handle with end
fitting on the left. Note the pair of dimples on the shaft.
Photo 3 - The hacksaw
CAUTION -
Wear eye
protection. A hacksaw blade can be quite
brittle and if it breaks, sharp
metal fragments may fly off.
Clamp the metal part of the handle horizontally in a vise. Try to avoid
distorting the cylindrical profile of the handle while doing this.
Protect the
paint on the handle by placing a piece of thin cardboard, such as the
packaging of the duster, between the handle and the jaws of the vise.
Cut the end fitting off,
about half way between the handle and the release button, using the
hacksaw. You might want to protect the handle from accidental slips of
the hacksaw with a couple of layers of plastic tape while doing this.
Note that there is a wire spring inside the end fitting which is
aligned with the grooves and the button (Photo 4). Rotate the handle
in the vise to avoid having to cut through this. Also note that I tried
to wiggle the end fitting out of the handle and that the plastic
fatigued and broke before this happened. This was a lot of work and
failed. The hacksaw method is better.
To get the remnant of the plastic end fitting out of the handle, insert
the free end of the hacksaw blade into the handle and cut three or four
equally spaced slots through the plastic. Be careful not to cut
into
the metal handle. I cut two closely spaced
slots and it worked but four would have been better. Note the pair
of dimples near the end of the metal handle in Photos 2 and
4.
There are four pairs of dimples around the circumference of the
handle. These serve to hold the end fitting securely in the handle and
are also what make it so difficult to remove. You can see how far they
protrude inside the handle in Photo 5. Do not cut the slots at these
points. Remove segments of plastic by inserting a narrow tipped slot
screwdriver into the slots you have cut and prying them loose.
Photo 4 - Partly
removed
Photo 5 - Completely removed
The dimples make eight protrusions on the inside of the handle
which will prevent the plug
from being inserted. Use a small, round or half round file to remove
most of the height of these protrusions, without breaking through to
the
outside of the handle. You only need to remove most of a protrusion,
not all of it.
Put
the handle aside for now and move on to the hoop.
The
Hoop
A few words about wire
- The hoop is
made
of galvanized steel fencing wire. The wire we are currently using has a
nominal diameter of 0.120
inches, which is a hair's breadth narrower than 1/8th of an inch. The
only exact match for this size is 11 BWG. There are several different
systems for designating wire sizes, AWG and BWG being two of the
common ones. Many hardware store
employees
won't have a clue which system is used when they look up the wire on
the
store computer and tell you it is 11 gauge. If it happens to be 11
AWG, then it will only be 0.0907 inches in diameter and not quite stiff
enough for a net. Take a set of vernier calipers or a micrometer
with you and measure the wire's diameter before you buy it. If you
don't have calipers,
drill a 1/8th inch diameter hole in a piece of steel, aluminum or even
wood and take
it to the store. Try to fit the wire through the hole. If it is loose,
don't buy it but if it is
a close fit or won't quite fit, buy it. Stay away from annealed wire,
which
is very soft. The wire you need is quite stiff and a bit
difficult to work with but it is just right for nets.
While writing this
article, I have tried to make sure that the materials I bought several
years ago are still available. Home Hardware™ originally sold the wire
we use as item # 5421-340 (wire bottom
galvanized 100' 11GA) and it measured 0.120 inches in diameter. Four
years later, in January 2010, the same item is only 0.109 inches in
diameter,
which is 12
BWG, although it is still listed as 11 gauge. They currently have
no galvanized steel wire with a 0.120 inch diameter. Searching the web
for a substitute was frustrating, so I called a local farm supplies
company (M&R Feeds™ in Pembroke) and found 9 BWG galvanized steel
wire, which has proven to be a perfect substitute. It is slightly
larger, at 0.144 inches in diameter, but a little more stiffness isn't
a bad thing. The price is also good at $17 for 180 feet (enough for 36
nets)! You may have to look around a bit to find the right wire.
A
drawing
of the 15 inch diameter hoop, with dimensions, is shown in Figure 1.
Figure 1 - The Hoop
Forming
the hoop - You will need a piece
of wire about 4 inches longer than the finished length, so 60
inches for a 15 inch net.
CAUTION -
Wear gloves and eye protection when working with the wire. The
wire comes in a coil which may, or may not, be
under high tension. You will have to carefully release the bindings
holding the fence wire in the coiled state and if it is under tension,
it will abruptly
uncoil as you do this. Use heavy wire
cutters and
wear gloves and
eye protection when you do this, as there may be quite a bit of
energy released.
Use a flexible
measuring tape and mark a point 60 inches from one end of the coil and
cut the
wire off with the heavy duty wire cutters or a hacksaw. If you have
bolt cutters, they work
even better. Use a file to round
the sharp edges on the ends of your piece of wire.
The wire, as it comes
off the original coil, will probably have some twist in it, which will
make it take the shape of a
spiral that will not sit flat on a table top. After cutting off the
wire, pick up the hoop near one of the ends and allow it to hang
vertically from your hand. Look down,
from above, along the "plane" of the wire and you will notice where it
deviates
from a plane. Work your
way
around the hoop making small bends as you move towards the other end,
trying to flatten the spiral.
You do not need to straighten the wire out. The natural curve in the
wire is halfway to forming the hoop.
Measure the length of the wire again and mark the middle point (A in
Figure 1) with
a
marker. Now measure 1/2 the hoop circumference (47.1 ÷ 2 ≈ 23.6
inches) on both sides of the middle and mark these points (B in Figure
1) as well.
These two points are where you will bend the wire to form
the arms.
Find a piece of cardboard about 16 by 20 inches and draw a hoop
template on it (see Photo 6). A 6 inch ruler is
shown for scale. You will measure the
angles as you form the hoop and arms using this. The circle has a
radius of 7.5 inches and was drawn using a compass made from a piece of
scrap lumber and a small nail (shown in top half of circle in Photo 6).
Drill a hole near one end (on the left) just large enough so that
the tip of a permanent marker can make contact with the cardboard on
the other side. Measure 7.5 inches from the centre of this hole and
drill another hole a bit smaller than the diameter of the nail. Tap the
nail though this hole so that it protrudes about 1/8 inch on the other
side. Make a hole with the end of the nail at the cross 8" from the
left
and 8" from the bottom of the cardboard and draw the circle. Draw a
line through the hole you made with the nail to the right hand edge of
the cardboard and then draw a line through it 4 inches from where it
intersects the circle.
Photo 6 - Hoop Template
The wire is very stiff and the easiest way to bend it is to hold it in
the jaws of a vise and use a hammer (see Photo 7).
Photo 7 - Gripping the wire.
Photo 8 - Bend the wire away from the hoop.
The hoop is on the left and
in the plane of the photo.
Line up one of the pair of
marks you made earlier at B (blue mark in Photos 7 and 8) along the
top of the jaws so that the short
end
of the wire extends above the jaws and clamp it. The jaws of the vise
should be perpendicular to the plane of the hoop. Gently apply pressure
to bend the wire away from the centre of the hoop, keeping it in the
plane of the hoop and hammer at the bend nearest the vise until you
have almost a right angle (see Photo 8). Better to bend too little
than too much.
Form the other arm in the same manner.
Now check your angles against
the template and make adjustments until you have a pretty good match
(see Photo 9).
The arms will have to be held together to do this, since the wire of
the hoop still has the original curve that it had when it came off the
coil of wire. Final adjustments to the shape of the hoop can be made
after the hoop, plug and handle have been assembled. At this time, you
just want get the angles close.
Photo 9 - Angles Check
Put the arms on a flat surface and hammer any small bends out. Photo 9
was taken before this was done and you can see that the arms are a bit
kinked just to the right of Janet's finger. The arms need to be
straight or they won't lay flat in the V-grooves in the plug.
Now measure 4 inches
down each of the two arms of the hoop and draw a line with a
marker (see Figure 1). At these lines, use the vise and hammer to bend
the two tangs in
towards each other at a right angle, in the plane of the hoop. The arms
don't have to be exactly 4 inches but they do need to be the same
length, so try to make them match when bending the second tang over.
Trim the tangs off so that they are 0.25 inches long. Square the ends
with a file and bevel the edges slightly. Except for some minor
trimming, the hoop is now complete.
The Plug
The plug secures the
hoop to the handle and prevents it from sliding out of, or rotating in,
the handle. It is made from
a 5 inch long piece of 3/4 inch diameter hardwood dowelling. The
dowelling is available at hardware stores and at Canadian Tire™ (part
no.
054-9084-8, $2.49). The diameter of the dowelling is a little too large
to fit in the end of the handle, which has an inside diameter of 0.72
inches, but this can be fixed with a sanding block and about 15 minutes
of work. We use 80 grit sandpaper wrapped around a 4 inch long block of
1 x 2 inch wood.
Grip the 5 inch long section of dowelling horizontally in a vise and
start sanding.
Make 10 to 12 strokes with the sandpaper and rotate the dowelling about
1/8 of a turn and make another 10 to 12 strokes. Repeat this until you
have gone completely around the dowelling once. Bevel the ends of the
dowelling slightly with the sandpaper and try to fit it into the end of
the handle. Try one end of the dowelling and then the other. Unless you
have a calibrated wrist, you will probably sand a little more off one
end than the other. Continue until half of one end of the dowelling
fits
snugly into the handle then sand the other half until it fits snugly.
Use moderate force when inserting the dowelling and
don't insert it all the way.
You should be able to move it by gripping it firmly and using a
rotating motion. Once you have achieved a snug fit on both halves, you
can stop sanding.
The next step is to make two V grooves in the plug to hold the arms of
the hoop.
Photo 10 - Finding
Centres
Photo 11 - The Slot
Now you need to make lines
along the length of the plug on opposing sides (see Photo 10). Use
something to hold the tip
of a pen close to the centre of the end of the plug. We used a thin
block of wood but a magazine will work too.
Sliding the pen and block together make a line on the end of the
plug. Rotate the plug 180° and repeat. If the lines are not quite
parallel, don't worry. (You can always rotate the plug 90° and have
another try.) Hold the plug side-on to the pen and block. Rotate it so
that the space between the two lines on the end is centred on the pen
tip. Now, grip the plug firmly so it can't rotate and
slide the pen and block along the length of the plug, drawing a line on
it. Repeat on the other side of the plug. The lines may not be exactly
opposite each other but they are close enough.
A hacksaw will work fine for
cutting the slots but a wood saw will work better since it makes a
wider cut. Grip the plug
horizontally in a vise, with one of the lines facing up. Line up the
saw with the line and, as carefully as you can, cut a slot directly
along the line you drew (see Photo 11). The slot should only go as deep
as the diameter of the wire you are using. Once again, it needs to be
close, not perfect. Repeat on the other side.
Next, use a wood chisel to widen the slots out into two V shaped
grooves.
Wood chisels are supposed to be very sharp, so wear protective gloves
and eye protection. Note that in the Photo 11, I have already widened
the lower slot into a V shape. Photo 12 shows the appearance of
a finished V-groove.
Photo 12 - The finished V-groove.
You will need to periodically check that the groove is not too wide or
deep. The wire needs to stand a bit above the groove so that it will
bind against the inside of the handle when the plug and hoop assembly
is inserted.
Widen both grooves until about 1/4 of the diameter of the wire stands
above
the edge of the groove when viewed from the side. Take the hoop and set
one arm in each of the grooves, with the tangs hanging over the ends of
the plug, and try to slide the whole thing into the end of the handle.
If the tangs touch, file them
until they don't touch. If plug and hoop assembly goes in all the
way, with moderate to
high resistance, the grooves are wide enough. Note that the groove
in Photo 12 proved to be to deep, so go slowly and try the fit often.
Making the groove wider, rather than deeper, is advised. Since the
tangs are hanging over the end of the plug, you can clamp the part of
the hoop closest to the handle in a vise and pull on the handle to
remove the plug.
Fitting the Hoop to the Plug
You now want to drill
a 1/8 inch diameter hole between the two
V-grooves, near one end of the plug (see Figure 2). These will receive
the two tangs of the hoop. The tangs prevent the hoop wire from being
pulled out of the handle and stop it from rotating in the plug. To
locate the drilling point for the hole, line the arms
of the hoop up with the plug as shown in Figure 2. The ends of the
tangs will be resting in the bottom of the grooves at the point where
the hole needs to be drilled. To mark the location, lightly tap the
wire where it bends at the tang with a hammer. The round depression
left in the bottom of the groove is your location to drill. Once the
hole is drilled, you can give the an inch or so of the outside end of
the plug a light coating of paint with a spray can. Assemble the hoop
and plug as shown in Figure 2. The ends of the tangs should not touch
when they are fully inserted into the hole. File them to length if they
do touch. Now insert the hoop and plug assembly into the end of the
handle, leaving
about 1/16th of an inch of plug protruding. You should have to use a
moderate to high amount of force to do this. Line the hoop wires
up with
the dimples on the handle shaft. If you decide that
you need to remove the plug later, grip the part of the hoop closest to
the plug in a vise and pull on the handle.
Figure 2 - Hoop and Plug Assembly
You
now want to secure the handle to the plug using a wood screw. We use a
#4 x 5/8" flat head, brass Robertson wood screw. For our friends south
of the border, use a Phillips head. Neither of these have the sharp
edges of a slot head, which could snag the net material. Drill a 5
/64th inch diameter hole at the location of the second dimple in from
the end of the handle, as shown in Photo 13. Carefully countersink the
hole so the head of the screw only protrudes slightly above the surface
of the handle. After the netting has been assembled and installed, wrap
two layers of plastic electrical tape over the rough edge of the
handle next to the plug. This will protect the net material and your
fingers from
damage. Note that the end of
the plug has been painted black at this stage.
Photo 13 - Securing
the handle to the plug.
The Netting
The material used for the net is designer
tulle (pronounced "tool") and is available in 60 inch widths at
the Walmart™ fabric shop (item # and price not available) but
should be available at most fabric outlets. There is more than one type
of tulle material and some is fairly
stiff and not suitable for nets. The material you want is very soft and
very flexible. Photo 14 shows a close-up view of the fabric on a black
background. The scale is in inches. Note that the openings in the
fabric are hexagonal. Similar fabric with diamond shaped openings is
too stiff for a net.
The
finished edge of the fabric (solid material at the top) is called a
selvage and there is one along the each of the long edges of the fabric
as it comes off the bolt. The fabric and selvages do not stretch along
the length of the fabric ( horizontally in the photo) but are very
stretchy across the width of the fabric (vertically in the photo). This
presents some challenges when sewing the fabric.
Photo 14 -
Netting
Figure 3 - Fabric Dimensions
Figure 3 shows the dimensions of the fabric you will use. The selvages
are shown in gray. Buy at least 1.5 metres (≈ 60 inches) of fabric to
allow for squaring it up and to give you a bit to adjust the thread
tension on the sewing machine. When the fabric was cut from the bolt,
the edges may not have been cut square to the selvages. These
instructions take this into consideration.
Fold the fabric in half along the upper selvage, as shown in Figure 4,
allowing it to hang freely. If the fabric was cut square, the left hand
edges will line up. If not, you will see something like the diagonal
line on the left hand side of the figure. Keeping the selvages
aligned, lay the fabric out on a flat surface and smooth out any
wrinkles. Now pin the two layers of fabric together with a generous
number of straight pins (T's in the figure). Lay out a line 25 inches
from the fold in the fabric (dot-dash line) and carefully cut both
layers of fabric along the line. Remove the straight pins from the
fabric.
Now is a good time to take the excess material you just removed and use
it to adjust the thread tension on your sewing machine. If you are
having someone else sew the net, give them the excess fabric so that
they can do the same. Improper thread tension will result in the
stitching being either bunched up or too loose.
Figure 4 - Folding the
Fabric
Photo 15 - Pocket Layout
Unfold the fabric and fold the top edge over about 1-3/8 inches, as
shown in Photo 15. Pin it in place and edge stitch it together, along
the selvage, to form the pocket for the hoop wire (see Photo 16). Next,
fold the fabric again so that the hoop pocket is along the top edge, as
shown in Figure 5. Smooth out any wrinkles and use lots of straight
pins (light gray T's) to fasten both layers together so that all the
edges line up.
The bottom of the net can be round, square or tapered. The choice
depends on your personal preference. All will be about 36 inches deep,
measured from the top of the pocket, as shown in Figure 5. When you
have selected the form the net will take, draw it on the fabric using a
water soluble ink (a dry erase marker works well). Using more straight
pins, pin the two layers of fabric together along the net side of this
line and up the left side of the fabric, opposite the fold (on the left
in
Figure 5). Cut the excess material away (dot-dash line).
Photo 16 - Sewing the Pocket - The
pocket
Figure 5 - Shaping the Net
is on the left.
Sew the edges together, about 1/2 inch from the edge of the material
(see Photo 17). Sew only to within 6 inches of the hoop pocket (see
red line in Figure 5). If you sew any closer, you will not be able to
get the net
onto the hoop wire. If you are worried about the gap in the net you can
stitch it by hand, or by machine, after the net is on the hoop.
Photo 17 - Sewing the Edge - Note the
location of the
straight pin relative to the edge of the fabric.
The netting is now complete. Remove all the pins and turn it inside out.
Assembling the Net
Remove the hoop and plug from the handle.
Carefully thread the netting onto the hoop, being careful not to tear
the netting. Reinsert the hoop and plug into the handle, with the holes
for the wood screw lined up, and insert the wood screw. A couple of
wraps of plastic tape around the top of the handle covers up the metal
edge, preventing it from cutting your hand or the fabric.
If you are forgetful and apt to put the net down and walk off without
it, make a label using a laser printer (waterproof
ink) with your contact information and fasten it to the handle with
packing tape. Make the packing tape extend past the edges of the label
by
at least 1/2 inch for a waterproof seal.
Stand back and admire your work and be prepared for "net envy" on the
part of your fellow entomologists.
Photo 18 - The Finished Product
Net Technique
Preliminaries
During this section, I will use the following convention
regarding the net. The "hoop end" is the part of the netting attached
to the hoop and the "closed end" is the part of the netting farthest
from the hoop.
As a general rule, stealth is the preferred approach when netting
dragonflies but, as with all rules, there a many exceptions.
Experiment. What works for one species may be less successful with
another.
Basic Technique
The basic technique used with a net is to swing it over the dragonfly
until it is well into the net and then turn the handle more than
90°, so that the hoop wire seals the hoop end of the net,
preventing escape. Keep the hoop end of the net sealed in this manner
until you are ready to remove the dragonfly. Once the dragonfly is
trapped in the net, it tries to escape by flying upwards. Nannothemis
bella (Elfin Skimmer) is an exception to this rule. To remove the
dragonfly from the net you must invert the net, so that the closed end
of the net is highest, before rotating the handle to unseal the hoop
end. Hold the net handle in your left hand and use your right hand to
grab the closed end of the net. Raise the closed end up until the
netting is extended by its full length over the sealed hoop end. The
dragonfly will fly to the higher, closed end of the net and stay there,
ignoring the open hoop end of the net. Rotate the handle to unseal the
hoop end of the net and, keeping the net inverted by keeping your right
hand raised, insert your left hand into the open hoop end of the net,
up to the crook in your left elbow and rest the hoop wire on it. With
your right hand, lower the closed end of the net down near your left
hand (already in the net). Using both hands, try fold the dragonfly's
wings together behind its back and grip them between thumb and index
finger with a gentle pressure. Use the folds in the netting to restrict
the motion of the dragonfly and manipulate its wings into this
position. Now, very gently, pull the dragonfly's feet away from the
netting by pulling on the netting with your right hand. This will not
be easy. Once you have detached the feet from the netting be careful
not to let them get close to it again. Use your right hand to pull the
netting away from your left hand as you remove the dragonfly from the
net or put your right hand into the net and use it to shield the
dragonfly's feet from the
net.
I generally keep both hands on the net handle during a swing. Over
water, or in high scrub, I hold the very end of the closed end of the
net under the index finger of the hand closest to the hoop and release
it when I start my swing. This keeps the netting from getting wet or
snagged on a twig. An exception to this is the leaping swing, where you
time the top of the swing to coincide with a leap into the air. With
this technique, you can snag a dragonfly perched, or flying, up to
fourteen feet above the ground (varies with the height and agility of
the user).
Swing Variations
Dragonflies are encountered in three basic situations: perched,
hovering and flying.
Perched Dragonflies
If a dragonfly is perched on the ground, or near the end of a blade of
grass or twig, or on an isolated rock, there are two ways of getting it
into the net. If it is not too skittish, you may be able to drop the
net over it from above by elevating the closed end of the net in one
hand and swinging the net down over top of it with the other.
Push the net down over the perch as far as possible, to the ground if
you can. The dragonfly will fly up into the net and you can proceed as
above.
If it is likely to fly off when it detects motion, then you have to
attack more quickly. In the case where it is perched near the end of a
piece of grass or a twig, swing the net horizontally from behind the
dragonfly so that the lower edge of the hoop intersects the perch
two or three
inches below the dragonfly and follow through. When the dragonfly
detects your movement, and
takes off into the air, the net will brush the twig aside and be in a
good position to capture
it. If you manage to surprise it, then the collision of the hoop with
the twig will shake the dragonfly loose and into your swinging net.
Hovering Dragonflies
I have found that swinging the net up from underneath the dragonfly is
very effective when they are hovering two to three feet above the
ground or water. Approach slowly and see if you can get close enough
for the swing. If possible, approach from behind.
If you note that a dragonfly repeatedly returns to the same spot and
hovers there, try to position yourself inconspicuously while it is
away. Set your net close to the ground (or water) near the point where
it hovers and wait for it to return. Be patient.
If a dragonfly is hovering very close to the water while laying eggs,
then a horizontal swing is the best, preferably from behind. In this
situation, however, they are generally so preoccupied that Janet has
actually captured them by hand from her kayak.
Flying Dragonflies
Sometimes the darned things just won't land and you must net
them in flight. You can swing with, or counter to, the direction of
flight and there are arguments for and against both techniques. With
the direction of flight minimizes the impact of the net on the specimen
and possibly conceals the approach of the net but you have to swing
much more rapidly to catch up to it. Counter to the direction of flight
still requires a fast swing but gives it a head on view of the
approaching net and possibly results in a greater impact when it hits
the netting. From either direction, changing the direction of the swing
by 90° once the dragon fly is partly in the net helps.
Dragonflies will patrol an area, following a shoreline or a path
through the woods, in a circuit. It may take five or ten minutes for
them to fly by a particular point again on their route. Be aware of
this
behaviour and use it to your advantage.
As for other techniques, swinging from underneath requires spilt second
timing and the leaping swing requires an agility some of us no longer
possess. Try different techniques and see what works.
Dragonflies That Fly Down
As mentioned earlier, most dragonflies fly up into a net when
captured. Nannothemis bella (Elfin Skimmer) is a notable exception to
this rule. With this species, you need to capture them by swinging the
net down over them and then holding it against the ground. Lift one
edge of the hoop up a little and insert your hand to make the capture.
They are extremely small and delicate. If there is someone in your
group with small hands, they should do this. We have not tried holding
the net open with the hoop facing up but will update the page if we
have a chance to try it.
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©2010 by
Harry Adams and Janet Nelson. All rights reserved. This material
may not be reproduced, displayed, modified or distributed without the
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