What tools where used in medieval Britain?

Of course they used hammers. Most hammers were designed to perform specific tasks, driving posts, driving pegs, shaping iron, steel and other metals, but they were basically the same as modern or ancient hammers - a heay piece of metal on the end of a stick. There were cutting and shaping tools like chisels, axes, planes, knives, scissors(shears) and saws. And they would have had gripping and holding tools like pliers and tongs, as well as measuring tools like squares and dividers. This may seem pretty meager by today's standards but you might be surprised at what could be accomplished with these simple tools and maybe one or two specialized items. One obvious difference between medieval and modern tool boxes would be the absence of things like screwdrivers, wrenches, sockets etc. That's because screws and nuts and bolts as fastening hardware hadn't been invented yet.