"A Door for your Train Shed or Warehouse."
The following is an idea for making a overhead
door, and shows the basic set up needed to make your own. The
door can be used for any number of applications. I believe a
small DC electric motor can be used to open and close the door,
using the set up I used in the following, with out to much
trouble.
Making the door track.
When making the door tracks lay one over the other
to check that they are a good matched pair, before the glue sets
up all the way in case an adjustment is needed. Use 3/8" "I" beam
made by Plasti-strut to make the door track. The length of "I"
beam needed depends on the height of the door. The "I" beam I
used was 12" long. An extra length of beam had to be added to the
top to finish the door track. Your can make the cuts in the beam
on a band saw or with a hack saw blade. The lower end of the
curved section of the door track should be above the door
frame.
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| About 1" from one end of the
strut, cut slots through one side of the beam about 1/8" apart
for 3-1/4". Be careful not to cut into the other side of the
beam. |
Cut a 4" piece of beam and make a
45 degree cut on each end to glue in temporarily to hold cut
section in place till the rail is installed, then it can be
removed. Clamp the track in position till the glue
dries. |
Align the start and end cuts to
the 2" marks on the square to get the right bend in the
beam. |
Check for square after glue
dries. |
After the beams have dried you want to smooth the
inside of the beam so the door will slide freely. On the back side
web of the beam, in the curved section, fill with glue or green plastic filler to add strength to the cut portion of the beam.
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| Build your basic building and
door frame to size. Add track supports. Notice How the wood base,
[3/4" X 3/16"] for the track is covered with metal, from the edge
of the track to the siding. |
The track has been lengthened on
the top by gluing a piece of "I" beam to the curved section. A
piece of 1/4" dowel can be glued to the back side of the spliced
sections for extra strength. The track needs supported on
top. |
The door track support needs a
brace to stiffen it at the bottom of the doorway. For a better
look a solid square block can be used on a finished model then a
brace like I used. |
With the temporary brace removed,
finish the under side with a little green plastic filler to
smooth the cut part of the beam. Check that the distance between
tracks is the same from one end to the other. |
Making the Door
The door is made of S-core "plastic cardboard".
First cut a piece of s-core about 4" longer and a little wider than
the door opening to cut for fit. 1/8" smaller than the distance
between the web of the track beams was right for me. Make sure
when you cut the s-core that the cuts are square. You want to
make the door length from bottom to the upper the end of the
curved section.
Cutting the s-core
I ground off and rounded the tip of a blade for a
utility knife to use in cutting the slits in the back of the
s-core to make it flexible.
Leave the last three cells at the bottom of the door and five
cells 0n the top intact, you need the top section to help raise
and lower the door.
It looks better if all of the slits are close to the same
location in each cell. To make the long cuts in the cells, make a
small cut next to each rib to start, I have found it easier to
get straighter cut this way. Place the blade in the small cut
tipping the blade placing the tip of the knife against the bottom
of the cell next to the rib and using that as a guide make the
long cut.
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| Blade of utility knife modified for use
cutting slits in the s-core. |
Recycled s-core cut to size for door. |
Placement of blade to cut slit. |
Slits in s-core, they are not all straight but
it bends OK. |
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| Feed door in from bottom of frame. |
Holding the top of the door. Move it up and
down to check for points where it might bind. Smooth the track if
needed. |
The door should move freely to operate. If
you use the bottom of the door to move it has a tendency to
stick, but holding the top to move it doesn't. Notice on the bottom
of the door, three cells were not cut, this makes the door run in the track easier. |
How to open and close the door.
The operation of the door is relative simple. Just
a piece of line a couple of old thread spools, 1/4" dowel rod,
some scrap paneling, a rubber band from a bunch of Broccoli and a
small drive drum from an old tape deck. The motor is from a
Aristo-craft K-4 Pacific. The motor is just about worn out, but
is good enough to do the job.
The main part of the operation is how the line goes on the drum.
I believe that the pictures below show how the line goes on the
drum and I do not have to go in more details here.
A piece of bent copper tubing on the front acts as a guide for
the line. A pulley of some kind could be used if wanted. But the
tubing works just fine.
Wiring
schematic
for motor operation. The circuit is simple, two limit switches and a
*DPDT switch. The limits, upper and lower, stop the door travel and turn off the motor. The *DPDT switch controls motor direction and door travel. When the switch is thrown in either direction, open or close, the limits stop the door automatically, until the switch is thrown in the opposite direction, the door will go in the other direction till it trips the other limit.
Double pole, double throw switch.
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| Glued to the front of the model is a piece of
copper tubing to guide the line. The line is fastened to the top
of the door. A little slack in the line is OK, that way the motor gets a chance to start without a load. |
The two ends of the line pass through the end
to the drum [thread spool]. |
Note the difference in the two pictures of the
drum. In the left door is up, right door down. |
Any source can turn the drum. But I used and
old motor out of a Aristo-craft K-4 Pacific. I tried some other
motors that were bigger But they didn't have enough torque to do
the job. |
Movie clips of door operation.
Thanks for visiting.
