Joining sping steel?

[JAYoung]

I have a 1930s manual typewriter with a broken spring steel motor (which powers the carriage along as you type). It parted in mid-length, and the spring is about a quarter-inch wide, one mm thick and maybe five feet in length.
While I seek a replacement, which may be a tough search, is there any way to join the two lengths and still have an effective motor. Spot welding? Silver solder? Riveting?
Or will the application of heat doom any attempt?

 

[2oolhound]

You could find a place that makes bandsaw blades. They have a special spot welder for joining the ends. There should be some places locally in your area. Heat damage will be localized in a small area, not ideal but it should work.

Flat coil springs are quite common so you should be able to find something to fill the bill by googling "flat coil spring"

 

[yhprum]

Your typewriter spring sounds similar to a lawn mower pull start recoil spring, maybe you could find one that could be used.

 

[kerrynzl]

the spring is about a quarter-inch wide, one mm thick and maybe five feet in length.
?

Interesting combination of Imperial and Metric measurements

6mm x 1mm x 1500mm or 0.250" x 0.040" x 5' [or 60"]

 

[Dagny]

I have repaired very similar things with silver solder. Lay it flat and cut a very small piece of solder and place it right on the crack then hit it with the torch.

 

[Jim greengo]

Picture?

 

[4EyedTurd]

At work we have transport belts made from it and we join the ends with solid rivets. The belt is about 24” wide and a good 300’ long.

 

[toplessHO]

might consider a crimp connection similar to a **** splice
could be made with a small piece of tubing flattened.

 

[Fluxion]

McMaster-Carr has a few types of spring steel in various widths, I'd make a new spring. 1mm seems awful thick though.

 

[matt_i]

I have repaired very similar things with silver solder. Lay it flat and cut a very small piece of solder and place it right on the crack then hit it with the torch.

56% silver solder and some white flux, see at mcmaster carr or others.

Have to clean the ends some but it should be roughly as strong as A36 steel and will wet the ends and be cleanable with a file if excess material gets involved.

Some people scarf the ends to place the joint at a 45 degree angle (or so) but I'm not sure you have extra length or not.

Its not going to be flexible as in wound into a tight cartridge imo, but would be fine straight-line or in tension.

 

[JAYoung]

Here's what I wound up doing: I torched both broken ends red hot, then carefully formed counterposed 1/4 inch interlocking hooks and then cold pressed them together flat in a vise.
Rewound the spring back into the drum and it withstood enough tension to operate the typewriter.
I don't know how long it will last, but it's working now.

 

[BukitCase]

See if you can find something here -

https://www.mcmaster.com/strip-springs

HTH... Steve