topic Concentric/Coincident constraint for Coil Spring Axis? in 3D Part & Assembly Design

Concentric/Coincident constraint for Coil Spring Axis?

xPR1MUSx — Thu, 23 Oct 2025 15:24:43 GMT

I'm putting a captive screw with compression spring in one of my assemblies. The coil spring doesn't have any 'cylindrical' features or surfaces. I made a central axis, but when I try to constrain the Spring Axis to the bolt cylinder surface, it places the axis coincident/tangent to the surface, not concentric.

I always have the option to constrain Front & Right planes, but I would like to figure out how to get concentric mates with an axis.

Re: Concentric/Coincident constraint for Coil Spring Axis?

tbraxton — Thu, 23 Oct 2025 15:27:20 GMT

One option is to add a central axis to both components and then align the axes when assembling to get what is needed.

Re: Concentric/Coincident constraint for Coil Spring Axis?

KenFarley — Thu, 23 Oct 2025 16:28:12 GMT

I do exactly what @tbraxton recommends - I have an axis concentric with the bolt, hole, or whatever I'm trying to line the spring up with.

I also have datum planes in the spring model that let me use its ends to position bolts, when the need arises.

Re: Concentric/Coincident constraint for Coil Spring Axis?

anursingh — Mon, 27 Oct 2025 21:38:37 GMT

Hi @xPR1MUSx,

I wanted to see if you got the help you needed.

If so, please mark the appropriate reply as the Accepted Solution. It will help other members who may have the same question.
Of course, if you have more to share on your issue, please pursue the conversation.

Thanks,
Anurag