Forming extension spring eyes?
I need to make a couple of springs for the boat, about .625 OD and 14" long or so. I think the wire is around .075, 302SS. These are extension springs. I can get a raw coil of spring but have had lots of problems trying to create a ring eye in the end. This will be captured by a roll pin, the whole thing ends up inside a tube. When extended, they are pretty much at the limit of extension for that spring.
So how do I go about bending the end to form the eye? I have not been able to grab enough of anything to cold bend the wire without deforming the coils below it, I can make a nice one if I heat the wire but when it cools it is soft and will not hold the tension. There must be a trick to this: how do the manufacturers do it? Does it just take some special fixturing to cold bend it, or do they hot bend then re-harden? It is possible to re-harden 302 with no equipment and no knowledge?
A quick and dirty way is to position the spring so that a couple coils on the end are straddling the corner of an anvil. Then strike the side with a hammer. This will bend the 2 coils outward. Then you can cut and tweak as needed.
The size of the spring determines the size of the hammer.
Gloves are a good idea too.
This tutorial How to Make Springs will give you some ideas for tools & techniques for forming loops in the ends of springs.
Rich - that's a great little tutorial, just what I needed. Thanks!
Larry - The spring I have is .625 OD and .072 wire, but it is stainless which is softer than music wire. I cannot tell from the pictures how those pliers work - is there something in the design that is limiting diameter and wire size, or is it merely a strength capacity thing? If the latter, it might very well work on the springs I have.....
Two pairs of duck bill pliers would fit the bill for forming only four spring ends in your stainless spring wire. Use one one to hold the coil you want to bend up for an end, the other one to grab the coil below it. Rotate 90+ degrees to allow for spring back. Maybe 30 seconds each.