FED-STD-228A
Method 8111.1
18 APRIL 2014
DIRECTION OF LAY
1. SCOPE
1.1 This method is intended for use in determining the direction of twist of any helical element such as
strands, conductors, tapes, cotton wraps or servings, jute bedding, armoring tape, armoring wire, jute
serving, etc., of insulated wire and cable. For purposes of this specification, direction of lay is defined as
the lateral direction, either right-hand or left-hand, in which an element passes over the top as it recedes
from an observer looking along the axis of the wire or cable.
2. SPECIMEN
2.1 The specimen should be a piece of the inspection unit of sufficient length to include at least two
spirals of the element to be tested from which any covering over the element to be tested has been
removed.
3. APPARATUS AND REAGENTS
3.1 The apparatus and reagents shall be as follows:
3.1.1 Wiping cloth.
3.1.2 Alcohol or other suitable solvent.
4. PROCEDURE
4.1 The covering material shall be removed from the specimen and the elements to be examined
exposed and cleaned if necessary with the solvent and cloth. The direction of lay of the element shall be
recorded as right-hand or left-hand. The following definitions shall apply to the terms right-hand lay and
left-hand lay:
(a) Right-hand lay. A clockwise twist of the element away from the observer.
(b) Left-hand lay. A counterclockwise twist of the element away from the observer.
5. RESULTS
5.1 Unless otherwise specified in the detail specification, one specimen from each inspection unit shall
be tested.
5.2 The direction of lay of the helical element of the inspection unit shall be the result obtained from the
specimen tested.
5.3 The element of the inspection unit shall be designed and its direction of lay (right-hand or left-hand)
recorded.
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