Screw and Bolt

Short Description:

PRODUCT NAME.: SCREW
CORLOR: DUE TO ORDER
SIZE: DUE TO ORDER

Product Detail

Product Tags

Introduction

A screw is a combination of simple machines: it is, an inclined plane wrapped around a central shaft, but the inclined plane (thread) also comes to a sharp edge around the outside, which acts as a wedge as it pushes into the fastened material, and the shaft and helix also form a wedge at the point. Some screw threads are designed to mate with a complementary thread, called a female thread (internal thread), often in the form of a nut object with an internal thread. Other screw threads are designed to cut a helical groove in a softer material as the screw is inserted. The most common uses of screws are to hold objects together and to position objects.

A screw will usually have a head on one end that allows it to be turned with a tool. Common tools for driving screws include screwdrivers and wrenches. The head is usually larger than the body of the screw, which keeps the screw from being driven deeper than the length of the screw and to provide a bearing surface. There are exceptions. A carriage bolt has a domed head that is not designed to be driven. A set screw may have a head the same size or smaller than the outer diameter of the screws thread; a set screw without a head is sometimes called a grub screw. A J-bolt has a J-shaped head that is sunk into concrete to serve as an anchor bolt.

Details

Screws are usually made of steel. Where great resistance to weather or corrosion is required, like in very small screws or medical implants, materials such as stainless steel, brass, titanium, bronze, silicon bronze or monel may be used.

Galvanic corrosion of dissimilar metals can be prevented (using aluminum screws for double-glazing tracks for example) by a careful choice of material. Some types of plastic, such as nylon or polytetrafluoroethylene (PTFE), can be threaded and used for fastenings requiring moderate strength and great resistance to corrosion or for the purpose of electrical insulation.

A surface coating is used to protect the fastener from corrosion (e.g. bright zinc plating for steel screws), to impart a decorative finish (e.g. japanning) or otherwise alter the surface properties of the base material.

Selection criteria of the screw materials include: size, required strength, resistance to corrosion, joint material, cost and temperature.

Our Service

1.Q: Can you offer mould making services?

A: We have made many mould for different customers for years.

2.Q: How about the guarantee period?

A: It varies according the different kinds of product. We can negotiate it before place an order.

3.Q: How about the scale of your factory?

A: Our total area is 7200 square meter. We have 150 staffs, 20 sets of punch machines, 50 set of riveting machines, 80 sets of point welding machines and 10 sets of automation equipment.

4.Q: What is the cost for the customized mould? Will it be returned?

A: The cost varies according to the products. And I can be returned depends on agreed terms.