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Basic Info.
Product Description
15 inch long music wire auto-lock spring for garage door
Commonly used torsional or compression springs mounted on the mandrel or a shaft of a door hinge to apply pressure onto the hinge's plates when a door which is pushed open is required to close automatically after it has been released.
#1 ATTN: Read This Before BuyingA. 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, and 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 inquire.
D. We appreciate your inquiries and you are welcome all the time!
For a better understanding of your demand, please learn the basics of compression spring manufacturing.
#2 Working Drawing of a Compression spring
#3 Different End Types of Helical Compression springs
There are basically four types of ends, closed & ground, closed & not ground ends, open & ground ends, and open & not ground ends. Below is a diagram for illustration. 
#4 Different Shapes and Applications of Helical Compression Spring
Compression springs are helical or spiral-like springs. They demonstrate an open-coiled design and react to axis forces to store and return energy. Manufacturers build compression springs into a variety of products, such as Automobile suspensions, Couches, Mattresses, Vending machines, Medical devices, Pacemakers, Pens, Hydraulic, Medical, Lawn equipment, Firearms, Marine industry, Underwater oil rig piping, Watches
Different products require different shapes to meet their demand. The below diagram covers the common shapes of compression springs, such as conical springs, barrel springs, variable pitch springs, and straight coil springs (cylinder springs) which are the most common springs, etc.
#5 Available Coating Method
Due to the government's environmental policy, all the coating materials are prior to RoHS standards. Please take RoHS standard coating as possible as you can.
| Coating Method | Cost | Does it Meet the RoHS requirement? | Remark |
| Unplated | None | Yes | |
| Anti Rust Oil | Lowest | Yes | |
| Stainless steel washing | lower | 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 |
| Electrophoresis | Higher | Yes | |
| Painting | Very High | Yes | require a longer delivery time |
| Stainless Steel Electro-polish | Highest | Yes | This coating cost more than the others |
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, and wire forms with a large range of High-Grade Spring Steel - Carbon steel - Stainless steel - Music Wire, all comply with the RoHS standard. The wire diameter is available from 0.001 inches to 0.075 inches, which can meet the requirement of different applications. All the spring materials meet European RoHS certification.
Q: Do you support orders in small quantities or do you only accept large runs?
A: DoFo Spring manufactures large quantity springs and small quantity springs based on your demand. We will work with you to choose the most effective solution.
Q: Does DOFO spring offer DESIGN OR initial ASSISTANCE ON SPRINGS?
A: Our engineers could help with the design with the drawing 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 layouts 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 quantities of springs, will you house the springs, and wire forms, and ship them to us based on a required basis?
A: Our warehouse provides specific stock services for long-term business. You can make your shipment schedule on an annual, or monthly basis. We will ship on a specific schedule.
Q: What payment terms do we accept for spring orders?
A: We could accept payment terms based on T/T, L/C at sight, DP, and Westunion.
If any question, please contact us directly.
