ETA 2451 mainspring issue

[ftwizard]

Before I contact Cousins, I thought I'd ask here first. I just bought a new mainspring, from Cousins, for an ETA 2451. It came in the usual washer thing, but the problem was, it didn't fit in the barrel. It just wasn't wound tight enough. In the end I had to remove it from the washer and fit it by hand, which is a right pain (I don't have any winders)

Is this a fairly commonl occurrence or am I just unlucky.

[jdm]

2 hours ago, ftwizard said:

Before I contact Cousins, I thought I'd ask here first. I just bought a new mainspring, from Cousins, for an ETA 2451. It came in the usual washer thing, but the problem was, it didn't fit in the barrel. It just wasn't wound tight enough. In the end I had to remove it from the washer and fit it by hand, which is a right pain (I don't have any winders)

Is this a fairly commonl occurrence or am I just unlucky.

Is that an original ETA MS that you bought? Which is the P/N?

[ftwizard]

I don't know, it's the recommended one from Cousins. Their part number is GR3271X

I've only changed a couple of mainsprings and all have been painless, until this one.

[jdm]

12 minutes ago, ftwizard said:

I don't know, it's the recommended one from Cousins. Their part number is GR3271X

That's a generic mainspring by size. If the indicated barrel diameter (10mm in this case) is larger than your application, it won't transfer straight from the washer.

[ftwizard]

Ah, I see.

I was under the impression that the spring that was recommended was the exact same size as the original. I see now, that it is as near as they can get. This particular one would be slightly to large in diameter.

Thanks. That clears that up.