12 volt dynamo producing 0.5v!

[Rex]

Not to the extent of the 12mm or so gap in the OP's pic though. Never yet seen any sort of armature where the armature coils' tails take a flying leap over open space to connect to the comm.

[trevinoz]

I have attached a picture of the 12V armature from the linked site.
I can see nothing unusual in the laying of the coil ends to the comm.
Have a look at modern machine wound armatures, you will see the ends with nothing beneath them and just a tie string around them.

[Rex]

So looking at the pictured armature, you think it would be possible to be able to move the comm around to solve the OP's problem?
I don't.

[RDfella]

I don't understand all this debate - either the part is correct and it fits or it isn't and it doesn't. Clearly the latter applies (assuming the correct bearing is fitted as I asked earlier, but even then it's unlikely to make that much difference). So send it back.

[Swarfcut]

Quite right RD. Either it matches an original, in which case the problem is something within the rest of the dynamo. Or it doesn't, in which case its not fit for purpose and goes back!

 Anybody got an original one handy for some comparative measurements?

 Swarfy.

[trevinoz]

The comm couldn't be moved with no access for a puller to move it out.
I have had success on an armature with the comm too far out by a small amount by pushing it back.
I agree with others, send the new armature back to the supplier.