[Public-List] right and left hand lay-- is this better?

[Randy Katz]

> Greetings, All,

>          Here is some hard core info about the lay of lines.  Some of this
pertains to wire rope.
> I was interested to learn what difference it makes whether one uses one or
the other of the lay directions. Apparently it may make some difference for
us in our uses.

>        I'm always surprised that such a seemingly simple quest for info
can lead to so much detail!
>
> Regards,
> Randy Katz
> #249
> Bellingham/Seattle, WA.
>
>      Read on....

> The characteristics of each lay are as follows:

>  from
http://www.starlifttrading.com/index.php?option=com_content&view=article&id=53&Itemid=122

Right Lay                     The most common lay

> Left Lay                       Used in a few special applications – cable
tool drilling line, for example

> Regular Lay                less likely to kink and untwist, easier to
handle, more crush resistant than langs lay.  Relatively poor wearing
qualities due to the point contact on the crown wires in the strand.
>
> Langs Lay                   Increased resistance to abrasion due to the
surface pressure being spread over a longer length of wire, greater
flexibility and fatigue resistance, has a tendency to kink and untwist and
so recommended only for use where the rope and load are secured against
rotation.

> RHRL or RHOL has the widest range of applications and meets the
requirements of most equipment.  In fact, other lay specifications are
considered exceptions and must be stated when ordering.  There are however,
the following exceptions.  Langs lay is recommended for much excavating,
construction and mining applications, including draglines, hoist lines,
dredgelines and other similar lines.  This is because langs lay ropes are
more flexible than regular lay ropes and they also have greater wearing
surface per wire than regular lay ropes which results in increased
resistance to abrasion.
>
> Where properly recommended, installed and used, langs lay ropes can be
used to greater advantage than regular lay ropes.  However, langs lay ropes
are more susceptible to the abuses of bending over small diameter sheaves,
pinching in undersize sheave grooves, crushing when winding on drums and
failing due to excessive rotation.  Left lay rope has the greatest usage in
oil fields on rod and tubing lines, blast hole rigs and spudders where
rotation of right lay rope would loosen couplings.  The rotation of a left
lay rope tightens a standard coupling.
>
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> from Wikipedia
>
> Left and right hand lay
>
> Left hand lay or right hand lay describe the manner in which the strands
are laid to form the rope. To determine the lay of strands in the rope, a
viewer looks at the rope as it points away from them. If the strands appear
to turn in a clockwise direction, or like a right-hand thread, as the
strands progress away from the viewer, the rope has a right hand lay. The
picture of steel wire rope on this page shows a rope with right hand lay. If
the strands appear to turn in an anti-clockwise direction, or like a
left-hand thread, as the strands progress away from the viewer, the rope has
a left hand lay. (The rope in the left hand lay photo shows one left hand
lay rope from left to right and top to bottom, with 5 right hand lay
strands, and part of a sixth in the upper left. It is not 5 right hand lay
ropes adjacent to each other.)
>
>
>
> [edit] Ordinary, Lang's and alternate lay
>
> Ordinary and Lang's lay describe the manner in which the wires are laid to
form a strand of the wire rope. To determine which has been used, first
identify if left or right hand lay has been used to make the rope. Then
identify if a right or left hand lay has been used to twist the wires in
each strand. (On ordinary lay, the outer wires approximately follow the
alignment of the rope: with Lang's lay they are cross at an angle of about
45°.) Lang's laid rope is able to flex over sheaves easier (with less
damage) but it has the disadvantage of having a high torque tendency (it
tends to untwist when tension load is applied) compared with ordinary laid
rope. Untwisting can be dangerous with a steel-cored rope: load is shed from
the strands and may cause the core to fail as it becomes higher loaded. For
this reason, swivel termination units can be dangerous.
>
> Ordinary lay--  The lay of wires in each strand is in the opposite
direction to the lay of the strands that form the wire.
>
> Lang's lay--  The lay of wires in each strand is in the same direction as
the lay of the strands that form the wire.
>
> Alternate lay--  Strands alternate between Lang's lay and ordinary lay;
e.g.: in a 6-strand wire, 3 strands are ordinary lay, and 3 are Lang's lay.
>
> Regular lay--  Alternate term for ordinary lay.
>
> Albert's lay--Archaic term for Lang's lay.
>
> Reverse lay--  Alternate term for alternate lay.
>
> Spring lay-- This is not a term used to classify a lay as defined in this
section. It refers to a specific construction type of wire rope.