are plumbing equipment used to attempt to unblock drains
and sewers. The set normally consists of several stiff, but flexible,
rods, each approximately one meter long, which may be screwed together
end-to-end. The material is often polypropylene heavy gauge tubing.
Jointing of the plastic to metal is done in hydraulic presses and
these joints are the achilles heel of this rod type. Often, when
subjected to force, the joint breaks. Better quality ends have
securing pins through the differing materials. More expensive rods are
high tensile steel. End connections are often brass or steel, the
better steel type having cadmium plating for corrosion resistance. Two
types of threaded end can be purchased. Cheaper ones simply screw
together, male to female but have the disadvantage of needing one-way
rotation in use to prevent unscrewing. Better quality rods have their
ends formed into a square peg, mating in a matching square hole in the
adjacent rod. A captive threaded nut then screw locks both lengths
together making a firm joint. A spanner tightens the joint firmly.
In use, this type of secure fixing enables rod rotation in both
directions which is often necessary to clear blockages. Tree roots in
particular often need 'winding up' before extraction and disposal. In
addition the drain rod set usually has one or two unblocking tools.
One may be a pivoting flat metal plate of almost half the drain
diameter. It is hinged across the widest point. This tool can be
rotated to ride over poor mortar joints or dragged over the joint to
scrape any protuberance. An auger can be screwed onto one end, it may
be a single helical coarse thread or even double helix. The latter
being ideal to capture thin young tree roots. Various rubber 'washers'
and bristle cleaning assemblies can be purchased too.
The screwed together rods and tool are inserted into a drain or sewer
from an access point usually a manhole chamber, sometimes a rodding
point or a clean out, and used to attempt to dislodge a blockage.
Rodding is the act of using a drain rod. It is usual to use a twisting
motion to facilitate progress of the rods and flushing with water
eases progress. It is important, no matter which way the rods are
being moved (towards or away from the blockage) to ensure the twisting
is in the direction to tighten up the screw connections as mentioned
above. Any unscrewing of the rods whilst in the drain or sewer will
lead to their loss and further blockage.
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