scsmith

scsmith

Well Known Member
I'm looking for a small spring hinge for an alternate air door. I think that Van's filtered air box design used for carbureted engines incorporates a spring-hinged door with a small magnet closure? What do people typically do? I suppose many put a control cable on the door and use it for carb heat. I just want a small door that will open in the event that the primary inlet is blocked, but will otherwise stay closed with a light spring (and internal pressure in the filtered air box).

Ideas?

I found some nice little hinges on Amazon, and the price was right, but the spring is WAY too stiff.
 
Recent search for source of Cowling hinge led me to McMaster Carr via suggestion from someone here. IIRC, they have 5052 material at 0.040" thick though they didn't mention spring torque that I could find. At those dims/material, you're probably closer to the right ball park versus some scary Amazon stuff. Could probably be mod'd to work
 
Per everyone's suggestions, I found what I think will be good torsion springs at McMaster-Carr. I was hoping for a complete COTS solution rather than have to make something. But I guess I'll cut a short length of piano hinge, grind a notch in one of the ears, and put a McMaster torsion spring in there. They do have lots of options about orientation of the legs, torque, etc. I think I got what I need.
 
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