Interfacing Pipe to the Real World
Speed Rail (c) (pipe) is normally attached to the rest of the world with flanges
or the pipe set into concrete. The floor and wall flanges are very useful to
us in the film business. Drilling a few holes for drywall screws is very handy
for lighter load applications. Drill your holes to maintain as much strength
of the fitting. I find that 4 dry wall screws into wood will hold moderate loads.
Don't hesitate to jump on, shake or rattle a rig to see if it will take more
than the load that you intend to put on it. Remember the stress when thing accelerate,
decelerate and get bumped.
6" stubs of pipe welded to about 3" square plates of 3/16" or 1/4" metal can
be very useful. If you use aluminum, make sure that it is weldable. It can be
coded with blue paint markings and 3000 or 6000 alloy numbers. Red paint and
2000 or 7000 alloy numbers are usually alloys that are not weldable. Check with
your metal supplier. I have welded for almost 40 years, but still send out my
structural welds to a certified welder. DON'T TAKE CHANCES.
If you are attaching to plywood, flat head bolts can be useful to maintain the
flat surface on the plywood. A triangular wall flange will require a flat head
bolt if the pipe needs to go through the fitting. A washer and nut has to go
on the other side. Washers are desirable under nuts and bolts to prevent them
from pulling through the plywood. You might consider buying one sheet of "marine"
plywood which has no voids inside and often has more ply. A coat of paint will
help preserve the plywood and color-code it "for rigs only". The paint might
also make it slightly more "professional" looking. Leave enough plywood near
a fitting so that the plywood doesn't fail from the holes that you have put
in the plywood.
When attaching to metal, taping the holes is often best, IF THE METAL IS THICK
ENOUGH. A 3/8"x16 taped hole in 3/16" steel would be safe, but in aluminum 1/4"
is barely strong enough. Holes taped in cast aluminum are weaker yet. Using
Helicoils will increase the strength of a taped hole and prolong the life of
the hole. Do not attempt to drill and tape holes with a hand drill without some
method to assure straight holes and tap alignment. Taping drill size and taped
holes in a block of aluminum done on a drill press can assure aligned holes
and taps when drilling by hand. Hold the block securely against the surface
being drilled and taped. Drilling and taping is not often a field process. Nuts
on the other side usually do the job in the field.
Always consider a more rigid shape than flat metal when attaching to something.
Angle and channel are stiffer per pound than plate. A triangle brace can greatly
increase stiffness. Larger, but thinner pipe can be much stiffer, although harder
to find or make fittings for. Fortunately in the larger pipe sizes, pipe telescopes
or almost telescopes so that fittings can be fabricated from the next size pipe.
Be careful to not score the wall of an inside tight fitting pipe with a set
screw and jamming the pieces together. Tight fitting aluminum joints can jam
when metal is pulled loose and piled up. Smooth surfaces, some lubrication and
anodizing will prevent jamming. For thinner sections of pipe consider a plug
inside the pipe to prevent the set screws of Speed Rail (c) fittings from collapsing
the pipe. Sked. 5, 1-1/4" pipe makes a very light weight (5 lb. per tube) overhead
frame for up to 12' x 12'. Be careful that the hi roller attachment doesn't
crush the pipe.
Drilling holes in pipe can provide bolt holes for attachment of things, BUT
HOLES WEAKEN THE PIPE. A 3/8" hole in 1-1/4" pipe doesn't effect it much, but
a 3/4" hole would greatly weaken the pipe.
Remember, ALMOST ALL THE PIPE THAT WE USE IS MUCH STRONGER THAN THE FITTINGS
THAT WE USE WITH IT. Steel Scaffold fittings are stronger than Speed Rail (c)
and Kee Klamp. Well placed triangulated braces can reduce the strain on anything
that you build.
Consider perforated telescoping square tubing for some applications. Unfortunately
the best sizes will not fit into Speed Rail (c) clamps. Consider perforated
steel angle, "Dexion" is a brand. Dexion makes a shear that cuts their angle
in a stroke.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.