UNC, 5/16", Cap Head, Socket Screw (12.9).
UNC, 5/16", Cap Head, Socket Screw/ Allen Bolt, High Tensile (12.9) BS 2470.
Fixaball.co.uk sells all lengths of self colour, 5/16", UNC, cap-screws at the best internet prices with free, first class delivery.
Orders placed before 2pm are usually dispatched same day (Mon-Fri).
Please make your size and pack quantity selection from the drop down menus at the top of the page.
The, ‘Socket Screw/ Allen Bolt,’ term is used to describe a fastener that is partially threaded in lengths over and around 1 inch generally speaking. The unthreaded area confirms that the fastener is a bolt. Some engineers may call them screws if the person uses the shorter length range of sizes, under an inch. ‘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.
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Fixaball.co.uk – Specialist Fixings and Fasteners UNC/ UNF Socket Cap Screws Conforming to ASME/ ANSI B18.3 1960 Series All measurements in Inches |
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|
Pitch TPI |
Head Diameter |
Shank Diameter |
Head Height |
Hex Key Size |
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|
Diameter |
UNC |
UNF |
Max |
Max |
Max |
Nom |
|
0 |
0.096 |
0.06 |
0.06 |
0.05 |
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|
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.
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