HEADING 73.18 - SCREWS BOLTS NUTS COACH SCREWS SCREW HOOKS RIVETS COTTERS COTTER-PINS WASHERS (INCLUDING SPRING WASHERS) AND SIMILAR ARTICLES OF IRON OR STEEL (+) .

62 COMMODITIES

- Threaded articles :

7318.11 - - Coach screws

7318.12 - - Other wood screws

7318.13 - - Screw hooks and screw rings

7318.14 - - Self-tapping screws

7318.15 - - Other screws and bolts whether or not with their nuts or washers

7318.16 - - Nuts

7318.19 - - Other

- Non-threaded articles :

7318.21 - - Spring washers and other lock washers

7318.22 - - Other washers

7318.23 - - Rivets

7318.24 - - Cotters and cotter-pins

7318.29 - - Other

(A) SCREWS BOLTS AND NUTS

Bolts and nuts (including bolt ends) screw studs and other screws for metal whether or not threaded or tapped screws for wood and coach-screws are threaded (in the finished state) and are used to assemble or fasten goods so that they can readily be disassembled without damage.

Bolts and screws for metal are cylindrical in shape with a close and only slightly inclined thread; they are rarely pointed and may have slotted heads or heads adapted for tightening with a spanner or they may be recessed. A bolt is designed to engage in a nut whereas screws for metal are more usually screwed into a hole tapped in the material to be fastened and are therefore generally threaded throughout their length whereas bolts usually have a part of the shank unthreaded.

The heading includes all types of fastening bolts and metal screws regardless of shape and use including U-bolts bolt ends (i.e. cylindrical rods threaded at one end) screw studs (i.e. short rods threaded at both ends) and screw studding (i.e. rods threaded throughout).

Nuts are metal pieces designed to hold the corresponding bolts in place. They are usually tapped throughout but are sometimes blind. The heading includes wing nuts butterfly nuts etc. Lock nuts (usually thinner and castellated) are sometimes used with bolts.

Blanks for bolts and untapped nuts are also included in the heading.

Screws for wood differ from bolts and screws for metal in that they are tapered and pointed and they have a steeper cutting thread since they have to bite their own way into the material. Further wood screws almost always have slotted or recessed heads and they are never used with nuts.

Coach screws (screw spikes) are large wood screws with square or hexagonal unslotted heads. They are used to fix railway lines to the sleepers and to assemble rafters and similar heavy woodwork.

The heading includes self-tapping (Parker) screws; these resemble wood screws in that they have a slotted head and a cutting thread and are pointed or tapered at the end. They can therefore cut their own passage into thin sheets of metal marble slate plastics etc.

The heading also covers all unpointed drive screws (or screw nails) and also those which are pointed provided that their heads are slotted. Drive screws have very steep threads and are often driven into the material with a hammer but often can be withdrawn only by use of a screwdriver.

This group excludes :

(a)Pointed screw-nails with unslotted heads (heading 73.17).

(b)Screw stoppers (heading 83.09).

(c)Threaded mechanisms sometimes called screws used to transmit motion or otherwise to act as an active part of a machine (e.g. Archimedian screws; worm mechanisms and threaded shafts for presses; valve and cock closing mechanisms etc.) (CHAPTER84).

(d)Piano pegs and similar threaded parts of musical instruments (heading 92.09).

(B) SCREW HOOKS AND SCREW RINGS

These are used to suspend or fix other objects and differ from the hook-nails of the preceding heading only in that they are threaded.

(C) RIVETS

Rivets differ from the goods described above in that they are non-threaded; they are usually cylindrical with round flat pan shaped or countersunk heads.

They are used for the permanent assembly of metal parts (e.g. in large frameworks ships and containers).

The heading excludes tubular or bifurcated rivets for all purposes (heading 83.08) but rivets which are only partly hollow remain classified in this heading.

(D) COTTER-PINS AND COTTERS

Cotter-pins usually of bifurcated form are used for fitting in holes in spindles shafts bolts etc. to prevent objects mounted thereon from moving along them.

Cotters and taper pins are used for similar purposes but are usually larger and more solid; they may be designed like cotter-pins to pass through holes (in which case they are often wedge-shaped) or for fitting into grooves or slots cut round the shaft spindle etc. in which case they may be of various shapes such as horseshoe or conical.

Circlips are produced in different forms ranging from a simple ring with a gap to more complex shapes (with eyelets or notches to facilitate application by means of special pliers). They are always intended whatever their shape to be placed in a groove either around a shaft or inside a cylindrical bore to prevent the relative movement of parts.

(E) WASHERS

Washers are usually small thin discs with a hole in the centre; they are placed between the nut and one of the parts to be fixed to protect the latter. They may be plain cut split (e.g. Grower's spring washers) curved cone shaped etc.

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Subheading Explanatory Notes.

Subheading 7318.12

The term " screw " does not cover screw hooks and screw rings; these are classified in subheading 7318.13.

Subheading 7318.14

This subheading covers the Parker (self-tapping) screws described in Explanatory Note to heading 73.18 Part (A) eighth paragraph.