|Fireplace cranes are those swing-out arms that you see in historical fireplaces and in old pictures and movies but increasing more in the modern home. They were used traditionally to heat hot water and keep soups and stews warm and occasionally for other things but were never a primary cooking tool.
To set up a crane correctly you need to be able to adjust the positioning of the pot you will be using with it relative to the heat source. That means vertically and horizontally. That way you can move the pot both side to side and up and down to regulate the cooking temperature.
To get horizontal range you need to make sure the crane is long enough. We recommend the next size up from 1/2 the width of your firebox. To get vertical range, you need either s-hooks or a trammel. While a trammel is a cool tool, it is less practical (it was meant for much higher foreboxes) and has less of a range than the s-hooks. Other than that you can always stoke or dampen the fire to control the heat as well.
If you are just starting to explore fireplace cooking, we recommend other appliances as a more versatile and easier way to begin. If you are building a fireplace, consider all of the above before investing in a crane.