UNF, 5/16", Socket Cap Screw, High Tensile/ 12.9, Zinc, DIN 912.

UNF, 5/16", Cap Head, Socket Screw/ Allen Bolt, High Tensile (12.9) BS 2470. ZINC Fixaball sells lengths of zinc, 5/16", UNF cap screws. What is a socket cap screw/ bolt? The, ‘Socket...
£2.90

UNF, 5/16", Cap Head, Socket Screw/ Allen Bolt, High Tensile (12.9) BS 2470. ZINC

Fixaball sells lengths of zinc, 5/16", UNF cap screws.

What is a socket cap screw/ bolt?

The, ‘Socket Cap Screw/ Allen Bolt,’ term is used to describe a fastener that is either fully or partially threaded. A screw is fully threaded and a bolt is partialy threaded. Some engineers may call them screws if the person uses the shorter length range of sizes. The thread stays the same length as the fastener gets longer and the maximum length of thread is equal to 2.5 times the diameter (or thereabouts). ‘Socket,’ refers to the hexagon shaped indentation found on the top of the fasteners’ head. Here, you can use a hexagon key (Allen Key) to tighten and loosen the fastener. 'Cap' refers to the cylindrical shaped head.

 

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Fixaball – Specialist Fixings and Fasteners

UNC/ UNF Socket Cap Screws

Conforming to ASME/ ANSI B18.3 1960 Series

All measurements in Inches

 

Pitch TPI

Head Diameter

Shank Diameter

Head Height

Hex Key Size

Diameter

UNC

UNF

Max

Max

Max

Nom

0

   

0.096

0.06

0.06

0.05

No. 1

   

0.118

0.073

0.073

1/16

No. 2

   

0.140

0.086

0.086

5/64

No. 3

   

0.161

0.099

0.099

5/64

No. 4

40

48

0.18

0.11

0.11

5/16

No. 5

40

44

0.21

0.13

0.13

3/32

No. 6

32

40

0.23

0.14

0.14

3/32

No. 8

32

36

0.27

0.16

0.16

1/8

No. 10

24

32

0.31

0.19

0.19

5/32

¼

20

28

0.38

0.25

0.25

3/16

5/16

18

24

0.44

0.31

0.31

7/32

3/8

16

24

0.56

0.38

0.38

5/16

7/16

14

20

0.63

0.44

0.44

5/16

½

13

20

0.75

0.50

0.50

3/8

5/8

11

18

0.88

0.63

0.63

½

¾

10

16

1.00

0.75

0.75

9/16

7/8

9

14

1.13

0.88

0.88

9/16

1

8

12

1.31

1.00

1.00

5/8

1.1/4

7

12

1.75

1.25

1.25

¾

1.1/2

6

12

2.00

1.50

1.50

1

High Tensile – 12.9 Grade.

Available Materials: Plain/ Self Colour and Zinc Plated.

Material/ Finish

Appearance

Level of Corrosion Resistance

Typical Application

High Tensile Steel

Self-Colour (black with no surface treatment)

Low, without further surface treatment

-          No exposure to moisture

-          Often Greased/ Oilied

High Tensile Steel - Zinc

Bright Shine – Blue to Yellow

Internal

-          Low exposure to moisture

 

 

UNIFIED THREAD STANDARDS 

The basic American standards for fastening screw threads as agreed upon by standard bodies of Canada, the United Kingdom, and the United States. They are a complete and integrated system of threads for fastening purposes. Their outstanding characteristic is general interchangeability of threads achieved through the standardization of thread form, diameter-pitch combinations, and limits of size

 

Unified National Coarse (UNC) is a thread form with a 60 degree flank angle rounded roots and flat crests. For a given diameter it has a larger thread pitch than an equivalent diameter UNF thread. The unified thread is based on inch sizes and was first standardised in 1948 unifying the Whitworth and American standard thread forms.

Unified National Fine (UNF) is a thread form with a 60 degree flank angle rounded roots and flat crests. For a given diameter it has a smaller thread pitch than an equivalent diameter UNC thread.

Unified National Extra Fine (UNEF) is a Unified thread form with a very fine (small) pitch that are typically used on instruments and parts requiring a fine adjustment.

Unified National (UN) thread form with a rounded root contour, applies only to external threads. (The UN thread form has a flat, or optionally, a rounded root contour.) The majority of fasteners with a Unified thread form (UNC UNF) have a rounded root contour i.e. are UNR threads.

Image is for illustrative purposes only