Building pallets involves two major manufacturing steps – manufacturing pallet cut stock and fabricating the pallets and boxes. Cutting pallet stock usually involves two types of cutting – crosscutting across the grain (or cutting to length) and ripping parallel to the grain (or cutting to the proper thicknesses and widths). This second cutting process is often called resawing which is certainly one of the most significant steps in pallet manufacturing.
Resawing varies from making a single cut, often resawing a piece of lumber down the center into two pieces of lumber of the same thickness, to making multiple cuts, often in one step.
For example, one of the common methods of resawing softwoods is to split a 1-1/2” board into two similar boards. Softwoods are measured on a nominal scale. After it has been surfaced, softwood lumber measures 1-1/2” thick. So, you can resaw it into two pieces that are a little under ¾” thick. Pallet manufacturers typically buy softwoods in varying lengths and qualities, but width and thickness choices are fairly standard.
Hardwoods are often sold on a full scale, starting with 4/4 and going up by quarters to 5/4, 6/4, etc. Larger pieces of hardwoods from the center of the log, called cants, can vary in size according to local practices, market conditions, competitive markets, etc.
The most cant sizes vary is from 3”x4” to as large as 6”x8”, with significant geographical differences. Regardless of the size of incoming cants, a pallet manufacturer has a rectangular piece of wood usually from eight feet to about 16 feet long. To process a cant into pallet lumber, it needs to be cut to the desired length and then ripped into deckboards or stringers. This method of resawing is typically done with either circular blade ripsaws or multi-head bandsaws.
High production can be accomplished on either a gangsaw or a multi-head bandsaw. A bandsaw has the advantage of a thinner kerf so you can get more pieces of lumber from a cant. On the other hand, a thin-kerf bandsaws leaves a significant amount of sawdust on the boards it cuts, which is a problem for companies that ship on pallets. Many pallet companies run bandsawn lumber through a deduster or have a dedusting process built-in to the bandsaw heads or blade guides.
The charts presented here provide information about each resaw covered. A multi-head bandsaw or gang saw cuts cants faster, while a single head saw, either band or circular, provides flexibility and versatility. Many pallet companies have a resaw line setup to process cants or lumber into either stringers or decking and have a smaller resaw (often a single head) for custom cutting. They try to establish cutting lines to be as efficient as possible but still maintain some flexibility.
If a pallet company is buying low-grade softwoods and remanufacturing them around defects, sometimes called defect cutting, it will typically have to focus more on crosscutting and then ripping and sorting finished deckboards and stringers which can be done on a single-head bandsaw or a circle ripsaw.