Flat Head UNC Screws – The Comprehensive Range for Every Application
Flat head UNC screws are the first choice for flush and visually appealing connections in the American standard. With a special 82° countersunk angle (as opposed to 90° for metric screws), they can be fully recessed into the material, ensuring a perfectly flat surface without protruding heads. This is not only a crucial advantage for aesthetics and aerodynamics but also minimizes the risk of injury and protects against snagging in dynamic applications.
Our range covers all common surface finishes and materials:
Stainless Steel (Inox): Offers maximum corrosion resistance, ideal for outdoor use, marine environments, and the food industry.
Zinc-Plated Steel: The zinc plating provides reliable protection against corrosion and gives the screw a shiny, decorative surface.
Plain Steel (unfinished): For industrial applications where the surface will be further processed after assembly (e.g., painting).
We offer these high-quality flat head screws with a variety of drives:
Hex Socket: For high torque transmission and a classic, secure fit.
Torx: The Torx profile enables optimal power transmission and minimizes the risk of cam-out, which is particularly beneficial for high-torque applications.
Phillips: The universal standard for quick and easy assembly, widely used in industry and crafts.
Slotted: The classic drive for traditional applications and restorations.
The versatile applications of these screws make them an indispensable range:
Vehicles & Motorcycles: Specifically for US cars, vintage cars, and American motorcycles that are manufactured to inch standards.
Industry & Mechanical Engineering: Suitable for US machinery and equipment where UNC threads are standard.
Agricultural Machinery & Road Construction: Robust connections for heavy-duty outdoor use.
Trax & Archery: For special fixings on off-road vehicles, trailers, and precision sports equipment.
Benefit from the long-standing experience of equipe bachofner gmbH and our extensive stock. Visit our online shop at www.zoll-schrauben.ch and find the right flat head UNC screw for your project.
Countersunk screw 1/4" - 20 UNC x 7/8"
1/4" - 20 x 7/8" countersunk screw with internal hexagon drive, UNC, length 22.23 mm
American coarse thread UNC
20 threads per inch
ASME/ANSI B 18.3-2002
Countersunk head 82°
Hardness RC 39 - 44
Class FIT 3A
similar to DIN 7991
Length including head 7/8" = 22.23 mm
Thread diameter 6.35 mm
Wrench size 5/32"
ex StockCountersunk screw 1/4"-20 UNC x 1" Inbus
ex StockCountersunk screw 1/4"-20 UNCx1-1/4" Inbus
ex StockCountersunk screw 1/4"-20 UNC x 1-3/4" Inbus
ex StockCountersunk screw 1/4"-20 UNC x 2" Inbus
ex Stock