High Torque Square Head Lag Screws

Xiaoguo® High torque Square head lag screws China– drive with a wrench, the coarse thread taps into wood for a tight hold. We cold‑form and heat‑treat them for strength. Ask for a discount on bulk.

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Product Description

The High torque Square head lag screws from supplier Xiaoguo®，we produce every day go through these processes.

Materials

The round steel wire from the steel plant, with the grade of 10B21 or Q235. Before entering the factory, the chemical composition and drawing performance must be tested. Only when they are qualified can they be put into production.

Cold heading

The cold heading machine cuts the steel wire into segments and then cold forms them into square heads using the mold.

Thread rolling

The thread rolling machine uses two thread rolling plates to extrude the threads. After thread rolling, the inner diameter and tooth shape of the threads will be inspected to ensure they are intact.

Heat treatment

Carry out continuous tempering using a mesh oven. The hardness is high after quenching and the toughness is good after tempering. Take samples from each furnace to measure the hardness to prevent it from being too brittle or too soft.

Surface treatment

According to the customer's requirements, conduct surface treatment on the High torque Square head lag screws and carry out salt spray testing for random inspection.

Packaging

The automatic weighing and filling machine fills bags according to the set weight, seals the bags, and labels the outer boxes.

High Torque Square Head Lag Screws

Working principle

The working principle of the High torque Square head lag screws can be divided into four steps:

Guide hole

A guide hole must be drilled in the wood before installation.

The function of the guiding holes is: to guide the screws to move straight, prevent the wood from cracking, and provide space for the compressed wood fibers.

Thread engagement

Insert the conical tip of the High torque Square head lag screws into the guide hole and tighten it with a wrench.When the thread is screwed in, it will forcibly squeeze the wood fibers of the hole wall.

Fiber locking

The compressed wood fibers will slightly spring back and tightly grip the threads.This elasticity created a significant amount of friction, firmly securing the screw in the wood.

The non-threaded section near the head

This part is mainly responsible for connecting the two wooden boards together.

High Torque Square Head Lag Screws

Mon	#10	1/4	5/16	3/8	1/2	5/8	3/4	7/8	1	1-1/8	1-1/4
P	11	10	9	7	6	5	4.5	4	3.5	3.25	3.25
d max	0.199	0.26	0.324	0.388	0.515	0.642	0.768	0.895	1.022	1.149	1.277
d min	0.178	0.237	0.298	0.36	0.482	0.605	0.729	0.852	0.976	1.1	1.223
d1 max	0.122	0.177	0.228	0.268	0.374	0.473	0.582	0.686	0.784	0.892	1.017
d1 min	0.107	0.16	0.21	0.25	0.354	0.453	0.562	0.665	0.76	0.867	0.987
ds max	0.199	0.26	0.324	0.388	0.515	0.642	0.768	0.895	1.022	1.149	1.277
ds min	0.178	0.237	0.298	0.36	0.482	0.605	0.729	0.852	0.976	1.098	1.223
s max	0.281	0.375	0.5	0.562	0.75	0.938	1.125	1.312	1.5	1.688	1.875
s min	0.271	0.362	0.484	0.544	0.725	0.906	1.088	1.269	1.45	1.631	1.812
e max	0.398	0.53	0.707	0.795	1.061	1.326	1.591	1.856	2.121	2.386	2.652
e min	0.372	0.498	0.665	0.747	0.995	1.244	1.494	1.742	1.991	2.239	2.489
k max	0.14	0.188	0.22	0.268	0.348	0.444	0.524	0.62	0.684	0.78	0.876
k min	0.11	0.156	0.186	0.232	0.308	0.4	0.476	0.568	0.628	0.72	0.812
r max	0.03	0.03	0.03	0.03	0.03	0.06	0.06	0.06	0.09	0.09	0.09
r min	0.01	0.01	0.01	0.01	0.01	0.02	0.02	0.02	0.03	0.03	0.03

FAQ

What are the differences between High torque Square head lag screws and hexagonal-head wood screws?

The head shapes are different. The square head is tightened with an open-end wrench or an adjustable wrench, while the hexagonal head is tightened with a socket.

How to choose between 304 and 316 stainless steel?

304 is suitable for general humid environments and ordinary outdoor use. 316 is used in coastal areas, docks, and chemical plants.

What tools are needed for installation?

Open-end wrench, adjustable wrench or special square socket.

What are the packaging options?

Bulk 25 kg cartons; small bags; boxes. For export, VCI anti-rust paper can be added.

Can we provide free samples?

Yes, we fully support purchasing the bulk quantity after testing the samples.