[Mr Charles]

Purchased RV-4 a few years ago and doing some modifications...what is the correct way to bend piano hinge pin wire? Bend it cold, or should it be heated with a torch first?
Charles

 

[Jerry Fischer]

hinge pins

I bent mine on the RV7 cold but radiused them 1.5 times the diameter of the wire. I used a vise and took my time. Just be careful not to nick or scratch the pin by using wood or plastic liners on the vise jaws and you should be OK.

 

[airguy]

I heated mine to a nice cherry red and bent them.

 

[fixnflyguy]

Bending hinge pins

Depends on what kind of bend you are making, as a basic 90 degree bend can be done "cold" if the radius is kept moderate. I too have a -4, and for my cowl side pins I made a full loop approximately 1/4" in diameter that accepts a screw at the forward end for retention. For that bend, I heated it red hot and bent the loop using rounded needle nose pliers. It will not affect the strength, however it will ruin the cad plating (gold color) and make it more subject to rusting. I used stainless hinge pin for mine simply becaue I had some, and dont heave to worry about corrosion. Some hinge pins are hardened and very brittle...bending without heat may cause it to break.