Speaking of heads, there are two common shapes you will find. Most metal-shaping hammers will have a slightly domed head, such as the hammer on the right. There are a few, like the Fairmount Shrinking hammer on the left, that have a perfectly flat head. Though they can be used interchangeably in a manner of situations, their effect is slightly different. The domed hammer will have a smaller point of impact and is more appropriate for curved surfaces, whereas the flat head spreads the blow out over a larger area. It’s fitting that the opposite head of the Fairmount Shrinking hammer has a flat head, since they are also more advantageous for stretching metal.