High-Quality Extension Springs with Ends Hook

Product Description

Product Description

high-quality extension springs with ends hook

Extension springs are designed to absorb and store energy as well as create resistance to a pulling force. It is initial tension that determines how tightly together an extension spring is coiled. 

#1 ATTN: Read This Before Buying 

A. Due to the internet and computer display solutions. The actual products may differ from
the pictures. Please contact our salesmen for further assistance.
B. All the extension springs, compression springs, torsion springs, wire forms can be made in customized demands.
C. We appreciate Drawing-Guide Production, Please send us a spring drawing as possible as you can when you inquiry.
D. We appreciate your inquiries and you are welcome all the time!

For a better understanding of your demand, please learn the basics of extension spring manufacturing.
#2 Working Drawing of an Extension spring


#3 Different Hook End Types of Helical Extension Springs
Various types of ends are used to attach the extension spring to the source of the force.  They include hooks or eyes at varying positions or distances from the body of the spring, reduced and expanded eyes on the side or in the center of the spring, extended loops, threaded inserts, and even rectangular or teardrop-shaped ends. By far the most common is the machine loop and crossover loop. These ends are made with standard tools in one operation and should be specified when possible to minimize cost.


Unlike compression springs, extension springs do not have a solid stop to prevent overloading. Because of this design stress levels are lower for extension springs than for compression. A special type of extension spring called a drawbar spring has a solid stop and is a type of compression spring with special hooks.

#4 Available Coating Method
Due to the government's environment policy, all the coating materials are prior to RoHS standards. Please take RoHS standard coating as possible as you can. Below is a table for reference, you can simply learn the cost of each coating method.

Coating Method	Cost	Does it Meet the RoHS requirement?	Remark
Unplated	None	Yes
Anti Rust Oil	Lowest	Yes
Black Oxide/Oxide	Lower	Yes
Normal Zinc coating	normal	No
Trivalent Zinc coating	High	Yes	Normally 8~10μ thickness, 48 hours without white rust
Nickel Plated	normal	Yes
Electrophoresis	Higher	Yes
Painting	Very High	Yes	require a longer delivery time
Stainless steel Washing	normal	Yes
Stainless Steel Electro-polish	Highest	Yes	This coating cost more than the others

 

FAQ

DOFO Spring provides a win-win service. Below we list answers to some of the questions our customers frequently asked. For anything unsure, please contact us, and we will respond within 12 hours.

Q: Which kind of materials are available? Do they meet RoHS certification?
A: DoFo Spring is able to manufacture different spring types of compression springs, extension springs, torsion springs, wire forms with a large range of High-Grade Spring Steel - Carbon steel - Stainless steel - Music Wire, all comply to the RoHS standard. The wire diameter is available from 0.001 inches to 0.075 inches, which can meet the requirement of different applications.

Q: Do you support orders in small quantity or do you only accept large runs?
A: DoFo Spring manufactures large quantity springs, small quantity springs based on your demand.  We will work with you to choose the most effective solution.

Q: Does DOFO spring offer DESIGN service OR initial ASSISTANCE ON SPRINGS?
A: Our engineers could give initial assistance on the design and advise to lower the production cost. Our engineer has years of experience in spring design. We could provide drawing format in CAD, 3D, and 2D design layout as well as prototype development.

Q: What is the typical lead time for custom springs?
A: The lead time varies in custom springs. For compression springs, extension springs, torsion springs, wire forms in our mold range, we are able to deliver within 25 days. However, for some complex shapes of springs, the delivery time would be around 30~40 days.

Q: Do you charge custom spring samples?
A: We make the custom springs sample charge as a subscription of formal order. In other words, the sample charge could be refunded when we receive the order. However, if your sample requires an additional mold, we will charge it.

Q: If we order large quantity springs, will you house the springs, wire forms, and ship to us based on a required basis?
A: Our warehouse provides specific stock service for long term business. You can make your shipment schedule on an annual, monthly basis. We will ship on a specific schedule.

Q: What payment term do we accept for spring orders?
A: We could accept payment terms based on T/T, L/C at sight, DP, Westunion.
 

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