You can use a wood hand-stamp or joiner's-stamp die set to punch or stamp letter or number impressions into wood. A standard die set includes metal punches of letters A to Z and digits 0 to 9. The specifically designed wood punches have steeper angled raised letters and digits than standard dies used for stamping metal. The steep angles of the wood hand stamps protect the wood's surface from crushing when the hammer strikes the die. Furniture makers, instrument designers, artisans and hobbyists use wood punches for permanently marking their wares.
Determine the placement of your lettering visually or by measuring for alignment precision. If measuring for exact placement, measure the letter from the crown, or raised cutting surface/face of the lettered die.
Put on the safety goggles to protect your eyes from any flying particles caused by hammering.
Grip the lettered punch, or die, mid-shaft with the pliers to save your fingers from injury during the hammering process.
Stand the die with the lettered-end down in place on your wood.
Take the hammer in your free hand and tap the top end of the punch softly and squarely.
Lift the die to check for stamp depth. If the letter is not deep enough, place the die back into the first imprint and hammer once more. Repeat until your letter depth is sufficient. For best results, practice on a scrap piece of wood from your project to get familiar with the force needed for that particular wood. Hardwoods such as oak and maple require a heavier hammering force than softwoods like pine or cedar.