The Carpenter is a basic Forestry block.
The Carpenter is used to craft many forestry items. (Letters, Stamps, Beealyzer, etc.)
The item slots in red are the crafting area of the Carpenter. The blue slot is where only a few specific items can be placed. One such item is the Crate. The green slot is where, should a valid recipe have been made in the red space, the item will be displayed. The bar shows the progress made on crafting it. The purple slot is where the item will be placed when crafted. The yellow slot is where a Capsule or Bucket is placed to deposit a liquid. The slots in orange are where items are placed to be used by the Carpenter to craft an item.
The Carpenter can be used to save storage space by crating crates, storing them in the same way Iron would be stored in an Iron Block.
The Carpenter requires Buildcraft Energy (MJ) in order to work. A Redstone Engine will not put any power into a Carpenter so you have to use a Stirling Engine or an even higher tier engine in order to be able to power the Carpenter. The more power you put into the Carpenter, the faster it will run.
The Carpenter is crafted with Bronze, Glass, and the item in the center, a Sturdy Casing.