Known for its rot and warping resistance, black locust wood is a good choice for fence posts because you want a post that lasts for years and is not easily damaged. Working with black locust might be tougher than with most fence post materials, however, because the wood itself is so durable. Nailing boards and drilling will take more effort than with other fencing.
Preparing the Posts
Have the posts cut to the appropriate size for the fence you're installing. Consider the height you want the fence to be and the depth of the frost line in your area. These two measurements combined is the minimum length of your posts.
Use a mechanical post driver (available from equipment rental stores) or a tractor auger to put your posts in the ground. If using the tractor auger, you'll need to backfill the holes with soil or gravel and tamp the fill down often during backfilling. Sandra Cooke, in "Wood Fencing that Works," recommends driving posts to make a hardier fence (see Reference 1).
Pre-drill nail or screw holes to save yourself time and effort during fence building, using a drill bit that is the size of the nails or screws you'll be using to attach the boards.