Robust Square Head Lag Screws Black Oxide Finish

After receiving the Robust Square Head Lag Screws Black Oxide Finish from China Xiaoguo®, which items can you check by yourself?

Dimensional inspection

Randomly select 20 pieces from different packaging boxes, and measure the total length, the distance between the corners of the head, the height of the head, etc. using a vernier caliper and a thread gauge.

Using the gauge block, the gauge block moves smoothly, and the stop gauge stops within three turns.

Hardness inspection

Test with a portable hardness tester.

Torque destruction test

It is recommended to conduct the test using professional equipment.Place the Robust Square Head Lag Screws Black Oxide Finish on the torque tester and apply torque until it breaks.

Salt Spray Test

Send the product to a third party for testing.

Installation verification test

Use the same wood and follow the normal installation procedure to screw in 10 screws. Check: Is the screwing process smooth? Are there any abnormal sounds? After fully screwing in, is the head tightly against the surface? When unscrewing in the opposite direction with a wrench, is it smooth? Are there any obvious damages to the threads?

Material confirmation

Spectral analysis can confirm the carbon steel grade and the composition of stainless steel.

Customized service

Standard-sized Robust Square Head Lag Screws Black Oxide Finish sometimes cannot meet special requirements. We can customize the following parameters based on your drawings or samples:

Customization of screws

Diameter: Products can be produced with diameters ranging from small to large.

Length: 20 mm to 400 mm

Thread length: The standard is partial threads. The thread length can be adjusted to the size you specify.

Square head size: The width of the opposite sides can be adjusted slightly. If you need to match a specific wrench, we can make the adjustment.

Material: Carbon steel of grades 4.8, 8.8, 10.9; Stainless steel of types 304, 316; Brass, aluminum alloy, titanium alloy.

Surface treatment: The basic surface treatment can be customized, and the thickness and color can be specified.

Tail shape: Standard conical tip, or it can be a pointed tip with a cutting groove.

Customized packaging

Besides making the Robust Square Head Lag Screws Black Oxide Finish, we also do custom packaging.

Packaging options – We’ve got different types. Based on your order quantity, we’ll suggest what works best. Both inner and outer packing can be made to your needs – print logos, specs, quantity, production date, or just stick on labels.

Special customization – Want to tell different lengths apart? We can paint a colored dot on the square end of the screw.

Anti‑rust oil control – We can use more oil or less oil, whatever you need.

Delivery method – We can do split shipments, VMI consignment, or emergency restock (48‑hour shipping from our overseas warehouse).