1. What Defines a Custom Gas Spring?

A custom gas spring is not a modified off-the-shelf model but a component engineered from scratch to match your unique application needs. It’s defined by four core customizable elements:

1.1 Force & Stroke

• Force: Specify the exact holding force (in Newtons) required at rest and during movement. For example, a medical bed backrest might need 500–800N to support patient weight, while a lightweight cabinet lid could require 80–120N.
• Stroke: Define the travel length (e.g., 200mm for a lid that opens 200mm). Suppliers typically maintain a ±2% tolerance on stroke to balance precision and manufacturability.

1.2 Mounting Configuration

Choose end fittings and brackets to integrate seamlessly with your assembly:

• Common fitting types: Ball joints (for pivoting motion in automotive/furniture), studs (threaded for industrial equipment), forks (U-shaped for heavy-duty mounting), eyelets (for pin-based connections).
• Example: A marine hatch might use stainless steel ball joints to resist saltwater corrosion and allow slight alignment adjustments.

1.3 Material & Environmental Adaptation

Select materials and coatings to withstand your application’s conditions:

• Base materials: Carbon steel (standard for dry, indoor use), 304 stainless steel (mild corrosion resistance), 316L stainless steel (heavy-duty corrosion resistance for saltwater/chemicals), or specialty alloys (for high temperatures up to 200°C).
• Coatings/seals: Zinc plating (rust prevention for indoor use), powder coating (scratch resistance), or Viton seals (chemical resistance for industrial settings).

1.4 Type & Functional Behavior

Add features to match how the spring needs to operate:

• Locking: Rigid locking (holds position with no movement, ideal for adjustable desks) or elastic locking (slight “give” for comfort, used in medical beds).
• Dampening: Controlled speed during extension/compression to prevent slamming (critical for heavy lids like truck toolboxes).
• Self-Retracting: Automatically returns to a default position (useful for foldable toolbox lids or equipment panels).

Fig. 1: Key components of a custom gas spring—end fittings, stainless steel tube, piston rod, and Viton seal—tailored to environmental needs.

2. How to Source a Custom Gas Spring

Choose a sourcing route based on your project’s complexity, timeline, and budget:

2.1 Online Configurators (Straightforward Needs)

Best for simple customizations (e.g., standard materials with specific force/stroke).

• How it works: Suppliers like Stabilus, Bansbach easylift, or JP offer interactive tools where you input force (N), stroke (mm), mounting type, and material. The tool generates a part number, 3D CAD model, and instant quote.
• Ideal for: Projects like a 300N, 150mm stroke spring with M8 studs for office furniture—no complex environmental or performance requirements.

2.2 Manufacturer-Led Customization (Complex Projects)

For high-stakes applications (aerospace, medical, industrial machinery) that need compliance with strict standards.

• How it works: Collaborate directly with a manufacturer (e.g., Lesjofors, ACE Controls) to share your specs. They’ll run FEM (finite element method) analysis to validate performance, create prototypes, and test against standards like ISO 13485 (medical) or AS9100 (aerospace).
• Ideal for: A gas spring for a surgical table that needs 1000N force, 316L stainless steel, and 10,000-cycle durability in sterile environments.

2.3 Distributor Customization Services (Middle-Ground Needs)

Balances speed and customization for projects that need minor tweaks to standard models.

• How it works: Distributors (e.g., McMaster-Carr, RS Components) combine stock components (e.g., a standard gas spring tube) with bespoke elements (e.g., custom brackets, specialized seals) to reduce lead times (2–4 weeks vs. 6–8 weeks for full manufacturer builds).
• Ideal for: A warehouse storage lid that needs a standard 200N spring but custom fork fittings to match existing mounting pins.

3. Best Practices for a Smooth Customization Process

Avoid delays, mismatches, or performance gaps with these four steps:

3.1 Document Your Application in Detail

Share clear, specific information to eliminate guesswork:

• Space constraints: Provide dimensions of the area where the spring will be installed (e.g., “max 80mm diameter tube, 350mm total length when extended”).
• Movement requirements: Describe how the spring will move (e.g., “needs to extend 180mm vertically to lift a lid from 0° to 90°”).
• Visuals: Include 2D drawings (PDF) or 3D models (STEP/IGES files) of mounting points—this avoids alignment errors.

3.2 Specify Environmental Conditions Early

Environmental factors directly impact material and seal choices—don’t overlook them:

• List exposures: Note moisture (bathrooms), salt spray (marine), chemicals (industrial cleaning), or temperature ranges (e.g., -40°C to 80°C for outdoor equipment).
• Example: A spring for a food processing plant should specify “stainless steel 304, FDA-approved seals” to withstand washdowns with sanitizers.

3.3 Request Detailed Performance Data

Ensure the spring meets your functional needs by asking for:

• Force-stroke curves: A graph showing how force changes during the spring’s travel (critical for applications where consistent force is key, like medical beds).
• Cycle life testing: Results of 10,000+ extension/compression cycles to confirm durability (e.g., “no force loss after 20,000 cycles”).
• Speed-of-travel specs: How fast the spring extends/compresses (e.g., “100mm/s extension to prevent lid slamming”).

3.4 Define Clear Tolerances

Specify acceptable deviations to align with your project’s precision needs:

• Force tolerance: ±5% is standard, but tight-tolerance applications (e.g., aerospace) may require ±2%.
• Length tolerance: ±1mm for most projects, but medical equipment may need ±0.5mm.

4. Example: Custom Gas Spring for a Marine Hatch

Let’s walk through a real-world scenario to see customization in action:

Project Requirements

• Application: Saltwater-exposed boat hatch (needs corrosion resistance).
• Force: 600N (to lift the 60kg hatch).
• Stroke: 300mm (hatch opens 300mm to full vertical).
• Mounting: Stainless steel ball joints (to allow pivoting and resist rust).
• Environment: -10°C to 60°C, daily salt spray exposure.

Manufacturer’s Solution

• Materials: 316L stainless steel tube and piston rod (max corrosion resistance).
• Seals: Viton seals (chemical/saltwater resistance).
• Mounting: 316L stainless steel ball joints with M10 threads.
• Testing: 15,000-cycle salt spray test (ASTM B117) with no force loss or corrosion.

Outcome

The custom spring fits the hatch’s 350mm installation space, lifts smoothly, and maintains performance after 2 years of marine use.

5. Final Takeaway

Custom gas springs solve problems that off-the-shelf models can’t—whether it’s extreme corrosion resistance, tight space constraints, or precise force control. The key to success is clear communication: share your application details, environmental needs, and performance goals upfront, and work with a supplier that specializes in your industry (e.g., medical, marine).

Would you like me to create a custom gas spring specification template? It will include fields for force, stroke, mounting, materials, and environmental conditions—making it easy to share your needs with suppliers and get accurate quotes.