Bending spring with heat

[over40pirate]

My shop cord reel broke the end off of the return spring.
it's a flat would spring, like a recoil starter spring, but a lot heavier. It's 11/16" wide and .050 thick.
I need to bend a "u" shape in the end of it.
I know I have to heat it to bend it but have a few questions:
1. Should I heat it and let it cool before bending cold?
2. Should I heat and bend while hot?
3. After bending, should it be heated, (and how much) and quenched (in what)

Don't want it to break soon after the repair

 

[matt_i]

Tricky stuff to do a "garage heat treat". My best guess is this. Heat with propane or oxyacet until a medium orange heat. For a thin section like that, don't apply the cone of the flame especially with oxyacetylene. Bend with pliers to suit. Air cool.

Personally I would leave it like that. Its going to be in the annealed, non-hardened state, but for the loop you don't particularly care. The tradeoff is it might wear thru someday but there's a lower chance it will fracture away.

My wild guess is the coil spring is oil quenched originally, and then tempered, but one risks the integrity of the rest of it especially with the tempering process.

The other good news with above is if it does eventually break off, you trim it back 3/4" and then try again. Probably wise not to test the maximum extension of it after either shortening process.

 

[over40pirate]

As there was enough spring to try numerous methods, I just clamped the end in the vice, and heated area with a small oxy/acet. torch, and bent it.
As there are always a number of coils of spring against the end, it doesn't get much pressure, until the cord is extended far.
It's working. Time will tell

 

[914wilhelm]

Some spring is really not that brittle. If there is plenty of spring, try a cold test bend to make a new hook. Typically you can get one or two bends in an area. More is when the metal work hardens and breaks.

 

[BD1]

Never did anything with a spring but did a fix by using a round key ring holder . It's the kind where you separate the two sides and set key in. I did this for neighbor on his lawn mower deck spring until I could get a replacement.

 

[zkling]

Depends on the spring material and how far you have to bend it. For the sharper bends it is best to get it red hot in the area, bend it, quench it and then temper it (med temp, let it soak and then cool down slowly).

 

[OccupantRJ]

I have reworked quite a few flat springs by heating and bending, then do a quick oil quench. After that, heat until the oil smokes. Put to use. They seem to hold up as long as originally.

 

[laser3kw]

I've done lawn mower recoil springs that way. heat until red shows, let cool, bend. But don't heat more than you need too.
You my have to try a couple of times to get it just right.

 

[A_Pmech]

You shouldn't have to heat it and it's not a great idea to do so.

 

[OccupantRJ]

1/16" x 5/8" flat wound spring don't take kindly to reforming the end without heat.

 

[laser3kw]

You shouldn't have to heat it and it's not a great idea to do so.

My first instinct was to bend it as is. Snap! whoops, try again, maybe bend slower? Snap! rinse, repeat.
Heating, as described above, seemed to give satisfactory results.

 

[Steevo]

Both of my air hose reels were bought with broken springs. Both times I simply heated and bent the new "U" ends, let them air-cool and re-assembled and both are working fine years later.
It is a common failure on spring return hose reels, and a common fix, too.

 

[gatorxxx]

Do you have the room to drill and rivet a hook on the end of the spring? If you can't heat and reform it, that might be an option.

 

[over40pirate]

Forgot to say, that I tried a cold bend. lol. It just snapped.

While looking for a spring, I found a place selling the cord reel. I don't think I will buy a new one, at $1800+ !!!!!

Guess it was worth the $25 I paid at a yard sale!