 The screen door closer has been used for years as an air cylinder for pneumatic
props, but how exactly do you make one of these work? I learned how to do this
with extensive research when building a
Trash Can Trauma (created by Carl Chetta)
a few years ago. After the research I decided to document all the details of how
to do this again in case I wanted to make more animatronics.
Lucky too, since I have had
occasion to use one again recently
and was happy that I was able to go
right to the store and buy the
correct parts. I also expect to use
them in the future as well, as they
are the cheapest way to achieve a
self closing air cylinder that will
work for years. This how-to will be
slightly different from the other
web sites you may find on the
internet, as this is a very
industrial type end product since
the air-in fitting is attached
properly and will last under heavy
abuse for years. The typical
instructions show how to force
large fittings into the very weak
walls surrounding the threaded
fitting of the closer. That type of
arrangement could prove not only
problematic possibly requiring
repairs, but more importantly IMHO
could be dangerous. Here are the
details for building an alternative
one that will work for a long time.
MATERIALS;
1)
"California Screen" Screen Door
Closer
(Model #VJ102CALBL)
1) Brake Bleeder Valve
(SIZE M7-1.0 x 33.8MM, Pep Boys
NO#3139551)
1) 15/64" Drill Bit
1) 7MM - 1.00 Metric Tap
1) Roll Teflon Tape
You will need to begin with a typical screen door closer like the one shown
above from your local hardware store. This one happens to be from Home Depot;
"California Screen" closer model #VJ102CALBL.
 The fitting needed to
get the air IN to your cylinder is an automotive brake bleeder fitting from Pep Boys,
the technical dimensions (this is important in the event you need to go to
another place to find the exact size that works with the bit and tap as
documented here.) is M7-1.0 x 33.8MM and the part number from Pep Boys for one
is #313955.1.
You will also need a 15/64" drill bit & 7mm - 1.00 Metric Tap as shown
here. Remove the air bleeder screw from the back of the door closer and using
the 15/64" bit, drill the adjustment screw hole out until you reach the end
of the aluminum, but do not drill all the way through. Stop the bit just before
the end so the air fitting will have something to stop solid against. While
drilling this out you should keep the closer and drill bit pointed upward to
keep all the aluminum shavings from going down into your cylinder cylinder . Now you
will tap threads for the automotive bleeder screw but stopping just shy of the
end of the hole just as you did with the drill bit. You will notice the bleeder
fitting has a hole running down the center of it that then stops at a junction
that routes the brake fluid to each side of the screw. Since you want clear,
uninterrupted air flow to your cylinder and also need the threads to run to the very
end of this fitting, you must cut
off the end of the screw that is
smooth as shown on the right of the
two fittings shown here. Use some
Teflon tape around the
threads on the fitting so your connection will be airtight and thread into the
back of the door closer. When you are done your cylinder should look like the photo
on the right.
This air cylinder produces 4 3/4" throw when fully extended and will require
about 30 lbs of pressure to actuate.
This should help you in your quest of creating your own pneumatic animatronic of
your own vision or to complete a project that refers to the screen door air cylinder
but doesn’t go into detail on how to do it and what parts to buy. If you would
like to see the air cylinder in use, you can visit one of my other how-tos on this
like the
Aerial Executioner.
Or, you can go directly to the next step you will need to activate your ram,
making an
Air Trigger.
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