Machine Screw

Types of Machine Screw

Pozi Drive

Triangular Thread

Set Screw

Shoulder Screw

Truss Head

Socket Head

CSK Head

Button Head

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The Guide To Machine Screw

Guide 1

What are the Machine Screws?

Guide 2

Parts Name of the Machine Screw

Guide 3

Machine Screw Material

Guide 4

Designation of the Machine Screw

Guide 5

Inspection of Machine Screws

Guide 6

Packaging of Machine Screws

Guide 7

Production Time of Machine Screws

Guide 8

Inquiry Required Content

Guide 1

What are the Machine Screws?

The term used for a threaded fastener, with or without a head(headless – as in set screw) so designed as to permit it to be properly assembled in a pre-formed internal threaded hole (or capable of forming its own thread) and secured by means of tightening the head.

Guide 2

Parts Name of the Machine Screw

Head: The head of the Machine Screw is performed on the top to provide a bearing surface.

Head Diameter: It is the diameter at the largest extremity of the head

Head Style: The type of head or top that is on the fastener. Such as a Round head or Hex head.

Length: The length of a headed fastener is the distance from the intersection of the largest diameter of the head with the bearing surface to the extreme point.

Shank: The shank is the smooth part of the Machine Screw which lies below the head and above the threads.

Thread: A thread is a triangle profile of a uniform section in the form of a helix in the external or internal surface of a cylinder. This is known as a straight or parallel thread to distinguish it from a taper thread, which is formed on a cone or frustum.

Pitch: Pitch is the distance; measured parallel to the fastener axis between corresponding thread profile points on adjacent threads and on the same axial plane. Used mostly in metric, where it is expressed in millimeters.

Thread Length: the distance between the extreme points of contact on the pitch cylinders or cones for two mating threads.

Guide 3

Machine Screw Material

Carbon Steel- Unhardened

Unless otherwise specified, machine screws shall be non-heat-treated low
carbon steel, such as 1006 through 1022, with a hardness of Rockwell HRB69-HRB100.

Carbon Steel – Hardened

When hardened machine screws are specified, they shall be made from low or medium carbon steel, such as 1018 through 1038, with or without boron, through-hardened to Rockwell C25- C38.

Stainless Steel

When specified, stainless steel screws shall comply with the chemical requirements of ASTM F837.

Guide 4

Designation of the Machine Screw

INCH FASTENERS

Machine Screw shall be designated by the following data in the sequence shown:
(1) product name, including head type and driving
provision and designation of the standard
(2) nominal size (number, fraction, or decimal equivalent)
(3) threads per inch
(4) nominal length (fraction or decimal equivalent)
(5) header point, if desired
(6) material
(7) protective coating, if required

See the following examples:

EXAMPLES:

(1) Slotted pan head machine screws, ASME B18.6.3, 1/4″- 20 x 1-1/4″, hardened carbon steel, zinc plated per ASTM F1941, Fe/Zn 3A.

METRIC FASTENERS

Machine Screw shall be designated by the following data in the sequence shown:
(1) product name, including head type and driving
provision and designation of the standard
(2) nominal size
(3) pitch
(4) nominal length
(5) header point, if desired
(6) material
(7) protective coating, if required

See the following examples:

EXAMPLES:

(1) Cheese head screw ISO 7048 – M5x20 – 4.8 – Tpye Z – ZP per ISO 4042

Guide 5

Inspection of Machine Screws

Vernier Caliper

Will use vernier calipers to measure the basic dimensions of Machine Screw, like head diameter/height, length and so on.

Thread Plug&Ring Gauge

Will use thread plug&ring gauge to test GO/NO GO, including metric thread (Coarse&Fine), inch thread (UNC&UNF).

Depth Gauge

Will use depth gauge to measure the depth of screw slot, such as hexalobular slot, cross recess, and other slots.

Coating Thickness Gauge

Will use coating thickness gauge to measuere the thickness of the coating layer, such as zinc electoplated.

Guide 6

Packaging of Machine Screws

Usual Packaging

Label: black text on white, no pattern and barcode

Carton: standard double corrugated neutral carton, bulking packing, maximum load bearing: 25kg per carton

Pallet: Europe Fumigation Pallet, 36 cartons per pallets, Width 800mm x Length 1200mm

Guide 7

Production Time of Machine Screws

Flow 01: Need 3 Days – Analyze Customers’ PO and Place Orders to the Factory

Flow 02: Need 10 Days – Purchase the Raw Material

Flow 03: Need 15 Days – Make Production Plan and Wait for Starting Production

Flow 04: Need 15 Days – Formal Mass Production

Flow 05: Need 7 Days – Send Out to Do Heat Treatment (if exist)

Flow 06: Need 7 Days – Send Out to Do Surface Treatment (Finish)

Flow 07: Need 7 Days – Packaging, Make the Shipment

Total Time: 60 Days to 70 Days

Guide 8

Inquiry Required Content

Let us know who you are, and we can contact you in time.

We will give you a more reasonable price.

Let us know your needed product well.

Let us know if the products need to do the heat treatment.

Zinc Electoplated or Hot Dip Galvanized Coating or Zinc Flake Coating…

Our MOQ is about 1 pallet (900KGS) per size.

If it is a customized package, we will send the carton/label to you by courier for confirmation before packaging.

We will make a more suitable production plan for you.

FOB (We usually quote based on FOB ), CIF, FCA

This information is important before mass production. We will adjust the production plan according to your requirement.

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