bearing upside down
over the bushing.
• Add the remaining
1/8” bushing and
then the lock nut.
Since this is a dry fit,
you may want to use
a standard #6 hex nut
to ease disassembly.
■ FIGURE 4
■ FIGURE 5
■ FIGURE 6
connecting wires to the reed sensor.
6-32 Tap — This is needed to tap a
small piece of brass tubing. These can
be purchased for a couple of dollars at
your local home center.
part epoxy on the edges before
inserting. Make sure you don’t get
epoxy on the center surface area of the
bearing or it won’t turn freely. The top
of the bearing should be flush with the
top of the PVC cap, as in Figure 4.
• Two-Part Epoxy — Needed to attach
a couple of the components.
STEP 3: Tap a small bushing.
Take a piece of 5/32 brass tubing
and using the 6-32 tap, add about half
of the threads to the end of the rod.
The best way to do this is to add a few
drops of machine oil. Make sure you
tap a single thread, then back it out to
clear the material. Once you have
1/2” of the brass tubing tapped, cut it
off. This will yield you a small 5/32
piece of threaded tubing.
At this point, you
should be able to
rotate the cap freely while holding the
hub in your hand. As you rotate the
PVC cap, you will probably notice
hat it is not perfectly centered. Mark
the point on the cap where it is the
furthest from the inside of the
anemometer hub, i.e., the area with
the most clearance.
• PVC Glue — Needed for connecting
various PVC pipe sections permanently.
• Hacksaw — This is needed to cut the
various lengths of PVC pipe.
Please note that you will most
likely need all these tools for all
three of the anemometers except for
the #6-32 tap.
STEP 1: Prepare the anemometer hub.
Drill a 1/8” hole into the center of
the anemometer hub. There is already a
small hole that will act as a guide (Figure
2). Once you have the hole drilled, use a
6-32 tap to thread the hole. As an
option, you can drill a slightly larger hole
and forego the threading. Make sure you
keep the drill straight as you proceed.
STEP 4: Create more bushings.
Cut a 1/8” piece of 3/16 brass
tubing and a 1/4” piece of brass tubing. Clean the edges so that they are
free from burs. It is important that the
cuts are straight or the anemometer
STEP 5: Dry-fit the assembly.
STEP 6: Attach the magnets.
Remove the PVC cap and bushings
from the assembly. Leave the machine
screw in place. About 3/8” down from
the edge of the anemometer hub,
attach one of the small Neodymium
magnets with some two-part epoxy.
Mix only a small amount of epoxy since
you can only mount one magnet at a
time. Do not get any epoxy on the protruding machine screw. Once the
epoxy has hardened, place a second
magnet on the opposite side of the
hub in the same position. Use the
protruding machine screw to help you
line up the second magnet. Again, mix
up some two-part epoxy and glue in
place. It is important that the magnet is
not more than 3/16” thick or there
won’t be enough clearance for the reed
that we will install later.
STEP 2: Prepare the PVC cap.
Drill a 5/16” hole into the center of
a 1/2” PVC cap. I recommend you
make the hold slightly off-center about
1/16” of an inch or so. This will give you
a bit more clearance when mounting
the reed. You should not be able to
press-fit the 5/16” bearing into the hole.
This is done by placing the cap upside
down on top of the bearing and gently
tapping the PVC cap. If the bearing
does not have a tight fit, use some two-
• Place a #6 stainless steel washer
onto a 1-1/4” #6 machine screw ( 6-32
is good), then insert the assembly
through the top of the hole you drilled
into the anemometer hub.
• Thread the threaded bushing onto
the machine screw that is protruding
inside the anemometer hub.
• Now place the 1/4” bushing over the
• Insert the 1/2” PVC cap with the
STEP 7: Prepare the reed.
If you purchased a reed relay from
RadioShack, you need to remove the
glass sensor from the relay. This is a
very simple process. Bend both of the
contact leads so that they are in line
with the relay. One of the contact leads
will be protruding through an opening
that is large enough for the glass
element to pass through. Simply pull on
this lead and the reed will separate
from the relay. One end of the reed has