Machine Screw, Countersunk Head, 6-Lobe/Machine, Hafren Fasteners

Product Details

Will I need a special screwdriver bit to install this screw?

Yes. This machine screw uses a TS20 drive and requires a matching bit for installation and removal. To avoid damage to the screw head, order the correct TS20 driver bit separately if you do not already have one.

What does the size “M4 x 20 mm” mean?

The M4 refers to the screw diameter, and 20 mm is the overall screw length. This makes it suitable for projects where you need a 4 mm diameter screw with a 20 mm seating length. Always check your part thickness and thread engagement before fitting.

Is this screw fully threaded?

Yes. The thread is fully threaded, which is helpful when you need consistent grip along the full length of the screw rather than only near the tip. This is commonly used for secure fastening in metal and similar applications.

What is the head type and why does it matter?

This screw has a countersunk head, designed to sit flush with the material when fitted correctly. If you are working with countersunk holes or need a smooth finish, this head style can improve appearance and reduce snagging.

Is it suitable for wet or outdoor use?

It is made from stainless steel, which offers strong resistance to corrosion compared with standard steel screws. That said, exact performance depends on the environment, such as coastal air or harsh chemicals, so it is worth checking suitability for your specific conditions.

Is the pack size enough for small repairs or bulk jobs?

This listing is a 100 pack, making it practical for both small repairs and repeat maintenance. If you regularly fit countersunk machine screws, having a larger quantity on hand can help you avoid delays when you need matching fasteners.

What should I check before ordering to ensure compatibility?

Confirm the thread size and length as well as the drive type. For this product you are matching M4 x 20 mm with a TS20 drive, and the countersunk head should suit your application and any pre made countersunk holes.