Description
UNC 1/4″ (20 T.P.I.), Coarse Pitch, High Tensile (Grade ‘S’/ 8.8), Self Colour. Allen (hex) Socket, Countersunk Head, Allen Screw/ Bolt, ISO 10642, B18.3, BS 2470
Fixaballsellsall lengths of 1/4″, UNC, countersunk socket screw bolts.
Socket Countersunk Screwscome as ‘sets’ and ‘bolts’.The, SET, term is used to describe a fastener that is fully threaded. Overa certain length (around 2.5 x the diameter) thelength the fastener will have a, ‘shoulder,’ or unthreaded area under the head (plain shank). This space of unthreaded area confirms that the fastener is now a bolt (socket countersunkbolt in this case) and is shouldered. Some people might simply call themsocket allen bolts,’ in association with the Allen, Hexagonal Key which is used to tighten and loosen the fastener. So, Socket, refers to the hexagon shaped indentation found on the top of the fasteners head.
How to measure a countersunkfixing/ fastener
The length of a countersunk fixing/ fastener is always from tip to the top.
Orders placed before 2pm are dispatchedsame day (Mon-Fri).
Standard, Free Delivery is Royal Mail, 2nd Class (2-5 days, most likely 2 days). For a faster delivery time, select 1st class or courier at checkout.
Please make your, ‘No. of Items in Pack‘, ‘Length‘, and pack ‘Quantity‘ selection from the drop down menus.
UNC, 1/4″ Allen Socket, CountersunkScrew/ Bolt lengths available:
FT – Fully Threaded
PT – Partially Threaded
| 1/4″-20×3/8″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×1/2″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×5/8″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×3/4″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×7/8″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×1″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×1 1/4″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×1 1/2″,(FT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×1 3/4″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×2″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×2 1/4″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×2 1/2″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×3″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
| 1/4″-20×4″,(PT) SOCKET COUNTERSUNK HEAD SCREWS UNC ALLOY SELF COLOUR |
High Tensile 8.8 Grade.
Available Finish: Plain/ Black/ Self Colour
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Fixaball Specialist Fixings and Fasteners UNC/UNF Countersunk Socket Screw/ Bolt Diameters and T.P.I.’s Conforming toISO 10642, B18.3, BS 2470 |
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Thread Pitch (Threads Per Inch/ T.P.I.) |
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|
Diameter |
UNC |
UNF |
|
No. 4 |
40 |
48 |
|
No. 5 |
40 |
44 |
|
No. 6 |
32 |
40 |
|
No. 8 |
32 |
36 |
|
No. 10 |
24 |
32 |
|
20 |
28 |
|
|
5/16 |
18 |
24 |
|
3/8 |
16 |
24 |
|
7/16 |
14 |
20 |
|
13 |
20 |
|
|
5/8 |
11 |
18 |
|
10 |
16 |
|
|
7/8 |
9 |
14 |
|
1 |
8 |
12 |
|
1.1/4 |
7 |
12 |
|
1.1/2 |
6 |
12 |
Self Colour, High Tensile 8.8 Material Properties
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Material/ Finish |
Appearance |
Level of Corrosion Resistance |
Typical Application |
|
High Tensile Steel (10.9) |
Self-Colour (black) |
Low, without further surface treatment |
No exposure to moisture Often Greased/ Oiled |
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 (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.
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.
Image is for illustrative purposes only.
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