Countersunk or Flat Head Screws
CSK HEAD SCREWS
Countersunk screws are also called Flat head or CSK screws. These screws have a flat head which tapers along the shaft.
Flat head screws are used for flush mounting of sections, usually where one part slides over another or one part is mounted on another. They are used with a countersunk hole to provide a flush, snag free fit.
Countersunk head screws, like button heads and low heads, are limited by configuration in their tensile strength capability. Because of this, they should not be used in applications requiring full strength, where Socket Head Cap Screws should be used.
Flat head screws require a matching counter in the workpiece.
The Countersunk head is preferred to obtain a flush and level finish without any projection in metal or plastic. They sink into the surface to give a smooth exterior finish.
The head angle for metric countersunk socket screws is 90 degrees up to & including M20 and 60 degrees over M20.
The head angle for Imperial is different – Unified is 82 degrees and British thread forms are 90 degrees.
Countersunk Head Machine Screws
CSK Phillips Screws
The Phillips screw drive (specified as an ANSI Type I Cross Recess and type H in ISO documentation) is among the most popular drive style for screws.
Cross recess H (Phillips) according to ISO 4757 has a conventional cruciform recess with all walls inclined, the end of the screwdriver having trapezoid webs.
The design is often criticized for its tendency to cam out at lower torque levels than other “cross head” designs.
Applicable standards for CSK Phillips Screws
- IS 7485 – Indian Standard
- DIN 965 – DIN [German] standard
- ISO 7046 – International Standards Organisation
- JIS B1111 – Japanese standard
DIN Sizes from M1.6
Micro Sizes now available starting from M1.0
Materials – Steel, Stainless Steel AISI 304 and 316, Titanium on request.
Download Datasheets:
Metric Thread
The Japanese standard is more popular for electronic assemblies due to the smaller head. We now carry JIS CSK Phillips screws in our standard stock range.
You can utilise the benefit of smaller head diameters for limited space applications.
SS-304 and SS-316 available in Black on request:
CSK Phillips now available in Micro sizes starting from M1.0:
CSK with 100 and 120 degrees head for greater space and weight saving applications:
ISO 5856 100 Deg CSK Phillips SS-304 A2 B4B05-100 – Download Datasheet
120 Deg CSK Phillips SS-304 A2 B4B05-120 – Download Datasheet
CSK Phillips now also available with Pre Applied Threadlocker Patch:
Unified Series
CSK with 100 degrees head for greater space and weight saving applications:
Additional Material options available below on request. Higher MOQ and longer lead times may apply.
Raised CSK Phillips
We also have a range of CSK Phillips Head with a raised head as per DIN-966. This special raised head gives a visually appealing rounded finish.
Applicable standards
- DIN 966 – DIN [German] standard
Sizes from M2 onwards
Materials – Stainless Steel AISI 304 and 316
DIN 966 RSD CSK Phillips SS-304 A2 B4B26 –Download Datasheet
CSK Slotted Screws
Machine screws that are slotted have the traditional slot that runs horizontally through the middle of the head and is intended for use with a flat blade screwdriver bit.
This design is becoming less popular as it does not give the best grip for tightening and is not friendly for automation or use with power tools.
Applicable standards for CSK Slotted Screws
- IS 1365
- DIN 963
- ISO 2009
Sizes from M1.0 onwards
Materials – Steel, Stainless Steel, Titanium
Additional Material options available below on request. Higher MOQ and longer lead times may apply.
Visit the Slotted Machine Screws page.
CSK Torx Screws
The hexalobular socket screw drive, known as Torx or 6-Lobe or star drive, uses a star-shaped recess in the fastener with six rounded points.
It was designed to permit increased torque transfer from the driver to the bit compared to other drive systems. This system features a 15-degree drive angle which provides high torque transfer.
Torx Screws do not have camout problems as no camout forces are created to push the driver up and out of the fastener recess.
Because of these advantages, Torx drive screws are very popular in the automotive and electronics industries and is preferred for automation and use with power tools.
6-Lobe Flat Head Screws are available as per ISO 14581.
Sizes from M1.6 onwards
Materials – Stainless Steel AISI 304 and 316.
CSK Torx Screws are also available in Black Finish
Allen CSK Screws (Hexagonal Socket Drive)
The Hex socket or Allen compatible drive is a common method of fixing screws. The width across flats of hexagon socket head screws is smaller than the WAF of hexagon head screws, permitting more economic design with smaller sizes.
The 6-Lobe (Hexalobular) drive is an improved version of this drive.
Allen Flat Head Screws are available as per ISO 10642 (similar to DIN 7991 which is now obsolete).
Sizes from M2 onwards
Materials – Stainless Steel AISI 304 and 316, Titanium.
SS-304 and SS-316 available in Black on request:
Also available in Unified Series
Additional Material options available below on request. Higher MOQ and longer lead times may apply.
DIN 7991 Allen CSK High Tensile Alloy Steel C3A05 – Download Datasheet
Countersunk Head Self Tapping and Thread Forming Screws
Self-tapping screws are different to traditional screws as they tap their own threads when screwed into either plastic, wood or metal.
CSK Phillips Self Tapping Screws
The Phillips screw drive (specified as an ANSI Type I Cross Recess and type H in ISO documentation) is among the most popular drive style for screws.
Cross recess H (Phillips) according to ISO 4757 has a conventional cruciform recess with all walls inclined, the end of the screwdriver having trapezoid webs.
The design is often criticized for its tendency to cam out at lower torque levels than other “cross head” designs.
Self Tapping CSK Phillips Screws are available as per DIN 7982.
Also available in Micro sizes:
CSK Slotted Self Tapping Screws
Machine screws that are slotted have the traditional slot that runs horizontally through the middle of the head and is intended for use with a flat blade screwdriver bit.
This design is becoming less popular as it does not give the best grip for tightening and is not friendly for automation or use with power tools.
Self Tapping CSK Slotted Screws are available as per DIN 7972.
Visit the Slotted Self Tapping Screws Page
CSK Torx Self Tapping Screws
The hexalobular socket screw drive, known as Torx or 6-Lobe or star drive, uses a star-shaped recess in the fastener with six rounded points.
It was designed to permit increased torque transfer from the driver to the bit compared to other drive systems. This system features a 15-degree drive angle which provides high torque transfer.
Torx Screws do not have camout problems as no camout forces are created to push the driver up and out of the fastener recess.
Because of these advantages, Torx drive screws are very popular in the automotive and electronics industries and is preferred for automation and use with power tools.
Self Tapping CSK 6-Lobe Screws are available as per ISO 14586.
ISO 14586 CSK Torx Self Tapping SS-304 A2 B4B28 – Download Datasheet
ISO 14586 CSK Torx Self Tapping SS-316 A4 B6B28 – Download Datasheet
CSK Torx Tri-lobe Thread Forming Screws for Metal
The hexalobular socket screw drive, known as Torx or 6-Lobe or star drive, uses a star-shaped recess in the fastener with six rounded points.
It was designed to permit increased torque transfer from the driver to the bit compared to other drive systems. This system features a 15-degree drive angle which provides high torque transfer.
Torx Screws do not have camout problems and provide high torque transfer, and so are very popular in the automotive and electronics industries and is preferred for automation and use with power tools.
Thread-rolling screws form their nut threads themselves when they are screwed into precut holes. This not only saves assembly and production costs, but also creates stable and secure connections.
Tri-lobe Thread Forming CSK 6-Lobe Screws are available as per DIN 7500.
DIN 7500 Tri-lobe CSK Torx Thread Forming Screws SS-304 A2 B4B19 – Download Datasheet
Visit the Tri-lobe Thread Forming Screws for Metal page.
JCPlas Thread Forming Screws for Plastics
The reliable thread forming screw for easy fastening into thermoplastics. The JCPlas screws are thread forming screws with a 30° thread form.
This feature allows the screw to make deeper grooves into the material and capture more of it between the threads, creating an even greater resistance to shear force while reducing stress.
Our screws are made from Stainless Steel AISI-304 Grade to provide a strong corrosion resistant assembly for a long life to your product.
JCPlas CSK Phillips Thread Forming Screws (~WN1413)
The Phillips screw drive (specified as an ANSI Type I Cross Recess and type H in ISO documentation) is among the most popular drive style for screws.
Cross recess H (Phillips) according to ISO 4757 has a conventional cruciform recess with all walls inclined, the end of the screwdriver having trapezoid webs.
Thread Forming Screw for Plastic CSK Phillips SS-304 A2 B4B67 – Download Datasheet
Also available in a black finish on request.
Thread Forming Screw for Plastic CSK Phillips SS-304 A2 BLACK U4B67 – Download Datasheet
JCPlas CSK 6-Lobe Thread Forming Screws (~WN1453)
The hexalobular socket screw drive, known as Torx or 6-Lobe or star drive, uses a star-shaped recess in the fastener with six rounded points.
It was designed to permit increased torque transfer from the driver to the bit compared to other drive systems. This system features a 15-degree drive angle which provides high torque transfer.
The 6-Lobe drive provides for a slipless installation with reduced operator effort and fatigue.
Thread Forming Screw for Plastic CSK 6-Lobe SS-304 A2 B4B73 – Download Datasheet
Also available in a black finish on request.
Thread Forming Screw for Plastic CSK 6-Lobe SS-304 A2 BLACK U4B73 – Download Datasheet
Visit the JCPlas Thread Forming screws page
CSK Phillips PT Screws
PT screws are Self-Tapping Screws suitable for both plastics and metal. With a blunt type F end, these are extremely versatile for small and mini assemblies of a number of different materials.
Our screws are made from Stainless Steel AISI-304 Grade to provide a strong corrosion resistant assembly for a long life to your product and are RoHS compliant.
The Phillips screw drive (specified as an ANSI Type I Cross Recess and type H in ISO documentation) is among the most popular drive style for screws.
Cross recess H (Phillips) according to ISO 4757 has a conventional cruciform recess with all walls inclined, the end of the screwdriver having trapezoid webs.
These are available from 1.0mm onward.
PT Screws CSK Phillips SS-304 A2 B4B71 – Download Datasheet
Now also available in Black Coated Finish
CSK Head Self Tapping Screws for Wood
Expandet Extra Outdoor Screws
Used in load bearing timber structures making it very unique.
Has fibercut and saw thread => suitable for fast fixing into wood.
Special ceramic coating technology permits outdoor use.
Can be used in ACQ timber without fear of corrosion.
These screws use the torx drive for slip-less fixing.
Surface coated with Ceramic coating technology.
High resistance in ACQ timber.
Screw design ensures easy & quick installation.
Expandet Extra Outdoor Wood Screws N1L42 – Download Catalogue
Chipboard Wood Screws
Chipboard screws, also called speed screws, are developed to prevent the problems arising with the application of the conventional wood screws in chipboard and different type of wood.
This type of screw can be used in chipboard and soft wood types without pre-drilling, due to its thin core diameter and sharp angle of the thread.
This sharp thread cuts into wood with lower splitting effects, while simultaneously reducing the insertion torque. This combination increases the battery life on the used power tools and has the advantage of saving production time. The pull-out forces are also more consistent from the reduced splitting. These are normally available fully threaded.
CSK Torx
CSK Torx Half Thread Raised Head Screws
CSK Pozi
Chipboard Screw CSK Pozi SS-304 A2 B4B39 – Download Datasheet
Chipboard Screw CSK Pozi SS-316 A4 B6B39 – Download Datasheet
CSK Head Self Drilling Screws
A Self-Drilling Screw is a Self-Tapping Screw with the added feature of a drill point. The drill point looks a lot like the point of a drill. It will drill a hole and form the mating threads in one operation.
CSK Phillips Self Drilling Screws
The Phillips screw drive (specified as an ANSI Type I Cross Recess and type H in ISO documentation) is among the most popular drive style for screws.
Cross recess H (Phillips) according to ISO 4757 has a conventional cruciform recess with all walls inclined, the end of the screwdriver having trapezoid webs.
The design is often criticized for its tendency to cam out at lower torque levels than other “cross head” designs.
Self Drilling CSK Phillips Screws are available as per DIN 7504O.
Useful for stitching sheets and various assemblies attaching metal and other materials to metal.
Note: When fixing softer materials to metal, consider using a plain washer under the head to prevent the head from digging into the soft material.
CSK Torx Self Drilling Screws
The hexalobular socket screw drive, known as Torx or 6-Lobe or star drive, uses a star-shaped recess in the fastener with six rounded points.
It was designed to permit increased torque transfer from the driver to the bit compared to other drive systems. This system features a 15-degree drive angle which provides high torque transfer.
Torx Screws do not have camout problems as no camout forces are created to push the driver up and out of the fastener recess.
Because of these advantages, Torx drive screws are very popular in the automotive and electronics industries and is preferred for automation and use with power tools.
Useful for stitching sheets and various assemblies attaching metal and other materials to metal.
Note: When fixing softer materials to metal, consider using a plain washer under the head to prevent the head from digging into the soft material.
Also available in special Bi-Metal Material with a Steel Drill Point. This helps drilling into harder material.
USAGE NOTES.
- Install in a countersunk hole matching the counter of the screw head.
- Do not overtighten. Keep within the suggested Torque values. Using a Torque control tool is recommended.
- Ensure assembly using a correct tool in good condition. Worn out tools can damage the socket.