A Round Metal
When you first purchase
the plans for a T-14 Purple Martin House, they give instructions on
how to build and mount it to a square treated lumber pole.
However, I have all round steel poles at my site and because of all
the questions I've been asked about how I mounted my T-14 to a round
metal pole, I decided to create some drawings that would show my
method. I realize that not everyone is mechanical in nature,
so I hope my drawings are clear enough for all to understand.
Hopefully between the drawings and descriptions, you'll be able to
make the pulley, safety strap and build the frame that mounts your
T-14 to a round pipe as I show on my page. It is important
that any housing for purple martins allows the vertical raising and
lowering of the house. This set-up does just that and it does
it easily without any effort on the landlords part. Since the
house is too heavy to handle by hand, it is assumed that a winch
with a 1/8 th or 3/16 th steel cable is used to lift the load.
The pulley at the top of the pole is grooved to accept any cables
within that size range.
DO NOT USE ROPE
FOR THIS DESIGN.
Rope is not
strong enough to handle these loads.
T-14 and Pipe Mounted Pulley System
following is the detail view of the pulley and safety strap at the
top of my pole that holds my T-14 martin house up. As can be seen,
the pulley is imbedded in the end of the pipe and held in place by a
5/16" x 2 3/4" long bolt. The pulley is centered in the slot with
washers piled onto the bolt on each side of it to keep it
centered. Any commercial machine shop can manufacture these
pulleys. Simply print out this drawing and bring it to
The dimensions for the pulley are:
2 3/4" Outside
.32" Diameter hole in the middle
wide x 1/4" deep cable groove, centered on width
width equals outside dia of pipe being used.
hole = clearance for bolt being used.
down 2" from inside of bend.
Width = 1"
This design works very well with a winching
The safety strap over the pulley is required to
prevent the cable from accidentally coming out of the pulley groove
and can be made from either steel or aluminum, however if made from
aluminum, rust is not an issue and it's much easier to work
The slot can be cut in the end of the pipe using a
hand held hacksaw. Take your time and make it as close to the
dimensions as possible. Then, drill the hole and add your
pulley and safety strap. Assuming you have already mounted
your winch, feed the cable through the pulley insuring you are
inside the safety strap. Then, string it down to the area
where you will be adding your frame. Add a goof thick washer
first, then double the cable back on itself and add a small cable
clamp to the end of the cable. This forms a knot at the end of
the cable which does not allow it to pull through the frame cable
hole. The washer simply gives it a smoother and flatter
surface to ride on the frames wooden surface.
The Mounting Frame
can be made from one 8 foot long piece of treated 2 x 4
lumber. Make sure you get one that is as straight and free of
knots as possible. This makes for a better job to start with.
following graphic shows the dimensions for the two blocks required
to mount the T-14 style house to a pipe. These blocks are
nothing more than 2 x 4's, and are used to make a frame that the
house sections are mounted to. The T-14 is made in 4 sections,
each mounting separately to the frame. To make the frame,
measure the width of the back of your T-14. That is the
dimension for the length of your two horizontal members. Now,
cut and make 2 of the following parts. A hand held drill and
jig saw are the only two tools required to make these parts.
While cutting, cut 2 - 18" long pieces of 2 x 4. These are the
vertical members that will be used to make the final frame
the holes are drilled in the two , use your jigsaw and cut them in
half along the centerline indicated. It is best to mark the
parts so they can be kept together. The cuts from a jigsaw may
not be perfect, but if kept together, the two parts will mate
your jigsaw, clean out the material between the two 1/4 inch
holes. This makes a slot when the parts are re-assembled which
allows the cable freedom for movement when raising and lowering the
house with the winch.
assembly can now begin.
the two rear portions of the horizontal members, screw them on to
the ends of the vertical members as shown in the 'Final Frame'
drawing below. This will give you a basic frame that doesn't
have any front halves to the horizontal members.
the frame to the pipe where it is to be mounted. Might need
two people to hold all the parts in place until assembly is
final. The following is said assuming the cable has been
threaded through the pulley at the top of the pole and is dead ended
on the downward end. (Dead ended refers to adding a clamp to
the free end of the cable forming a knot large enough so that it
won't pull through the cable hole).
frame is held to the back of the pole, place the up side of the
cable, (from the winch) in the half cable slot of BOTH horizontal
members. Repeat this procedure for the knot end of the cable
placing it in the half holes with the knot on the underside
of the lower horizontal member. Now place the front
half of the lower horizontal member in position and insuring the
cables are in proper position, screw it in place. Repeat for
the top front half horizontal member. This now gives you a
frame mounted on your pole as shown below.
will be greatly increased structurally with the addition of the 4
housing sections, but first I strongly suggest using some wood
preservative and then painting the frame before mounting the
the back of each house section, measure up 21 " from the bottom and
draw a horizontal line. Now screw a small block of wood about
a 1/2" thick and 2" long to the back of each unit with the bottom of
the block resting on the line. I used these blocks of wood to
rest my house sections on the TOP horizontal frame member so that it
would be easier for me to work with. The 21" allows for the
bottom of the house to be flush with the bottom of the frame.
You may want to make adjustments to this dimension depending on how
you want to mount your house. I mounted my long sections of
the house first.
and drill 4, 1/8" holes into the back of each long house unit about
the middle of the horizontal member, 2 holes for each member.
Then, using 4, 1 - 5/8" long galvanized decking screws, screw
each long unit in place. Now, the shorter sections of the
house can be added in the same fashion screwing into the vertical
members of the frame. When all done, you should have a T-14
mounted to a round metal pole as shown below.
can make a winch run of your house. As you turn the winch and
the house raises, notice the cable in the bottom cable slot.
It moves with the increase or decrease of the size of the winch
pulley. This is why there has to be a slot on the winch side
of the frame.
look closely under the house in the picture, you can see how I made
my lower horizontal members of my frame a little longer. This
allows my shorter units of the house to sit on top of the lower
horizontal and to be raised the thickness of the 2 x 4. I
preferred this look a little better than a perfectly aligned
other thing I do for all my martin poles. I make ground
sockets so that I can easily lift the main pipes out of the ground
should they require any kind of maintenance or to put them away for
the winter. My main pipes are Schedule 40, but if you feel
this may not be strong enough, then Schedule 80 is stronger and is
readily available, but the cost is higher.
Below is a
drawing showing how to make a ground socket from Schedule 40 pipe.
The main pipe diameter is 1.9 inches Outside Diameter. The socket
inside diameter is 2.06 and will allow the main pipe to fit down
inside of it very easily. Cut the notch at the bottom of the main
pipe to prevent twisting once installed. This ground socket should
be buried in concrete with the top of the socket at ground
level. Then the main pipe can be removed when ever
required. Also, with the top of the socket at ground level, no
one will trip over them and also, the mower will slip over the top
of them without ruining the mower blades. Then the main pipes
can be replaced any time you like.
pipes fit fairly loose in the socket, so what I do is push the main
pipe to one side and then place 2 - 16 penny spikes beside it down
into the ground socket. The heads of the spikes hold the pole
to one side so that it doesn't rock in the ground socket and can
easily be removed when the main pole needs to be removed.
If you decide on pipe sizes other than given, make sure the two
pipes will fit together before you do any work.
Back to Chuck's Purple Martin
This page created and
by Chuck Abare
The Registry of Nature Habitats
Copyright 1999 -
All Rights Reserved