Stainless Steel Brush Spring for an Automotive HVAC Fan Motor Application

Stainless Steel Brush Torsion Spring (click on thumbnail to enlarge)

Maverick Spring faced the challenge of manufacturing these Stainless Steel Torsion and Compression Springs under heavy cost pressure. For the Torsion Spring, the solution was a change in raw materials. By switching the raw material for the Torsion Spring from Stainless Steel Type 17-7PH to Stainless Steel Type 302 we were able to gain a significant cost advantage without compromising performance requirements. A subtle change in spring wire diameter, from 0.028” to 0.0285”, was required to maintain the requirements, and the spring was kept within all physical dimensions. In this application there was no need for the elevated temperature durability afforded by 17-7PH wire.

Stainless Steel Brush Compression Spring (click on thumbnail to enlarge)

In addition to dramatic cost savings for the Torsion Springs, Maverick Spring also reduced total energy use because the heat treatment protocol for Stainless Steel Type 17-7PH was replaced by a more economical protocol for Stainless Steel Type 302. Instead of the one hour minimum heat treatment at 900 degrees F that SS-17-7PH required, SS-302 only called for 20 minutes of inline conveyor belt oven treatment, at 550 degrees F. Our production speed was also high, as we produced 3,300 pieces per hour.

The time from coiling to finished product and inspection was reduced by two-thirds, which reduced the overall cost of non-quality.

In total, the selling price reduced by $6.00 per thousand pieces, which delivered more than $68,000.00 in savings to the customer in the first year alone.

In the case of the Compression Spring, a switch in raw material again provided significant cost-savings. First, we reduced processing costs for the Compression Springs by re-designing springs that initially required a secondary coating that met the 100 hour salt spray test. After the substitution of Stainless Steel Type 302-wire, and a slight increase in wire size to accommodate the new material, the new SS-302 spring maintained all the force characteristics of the original Music Wire spring. The increased raw material cost was more than offset by savings obtained by eliminating the secondary finish and handling. The price was reduced from 35 cents per unit, to 18 cents per unit—a 50 percent decrease in cost. As a result of the redesign, the client accepted Maverick Spring’s recommendation and did not pursue the initial plan of Music Wire with additional coating. In both cases, the Torsion Spring and Compression Spring realized cost-savings as a result of substituting SS-302 for the initial material. For more information about these projects or to learn about other services, please contact Maverick Spring.


Product Name

Stainless Steel Brush Spring for a HVAC Fan Motor Application


Originally 0.028″ Stainless Steel Type 17-7PH, Changed to 0.0285″ Stainless Steel Type 302 Nickel Coat

Inside Diameter

5.64 mm +/- 0.13 mm

Total Coils, free position

9.625, +/- 10 degrees

Load at full deflection

2.6 N, +/- 0.3 N

Production Speed

> 3,300 pieces per hour

Heat Treatment

550 degrees F, 20 minutes, inline conveyor belt oven


Bulk pack in recyclable containers to customer requirements

End Use

Brush Spring for HVAC Fan Motor – Automotive

Shipped to

Ontario, Canada and Queretaro, Mexico