When a cutting edge exits a workpiece, it pushes unsupported wood fibers outward, causing them to fracture and break away rather than slice cleanly. This damage ruins the cosmetic finish on the back face of the material. It is prevented by clamping a sacrificial backer board tightly against the exit surface or applying masking tape over the cut line.
Heard on the job
Make sure you clamp a scrap block under that stile before you drill for the hardware, or you'll get massive blowout.
Insider tip
A zero-clearance insert on a table saw is the most effective way to prevent bottom-side blowout when ripping or crosscutting.
Also heard as
- tear-out
- spelching