Inlay techniques

The three approaches

	V-carve inlay	Flat inlay	Resin inlay
How it works	Matching V-shaped pocket and plug that wedge together	Flat bottomed pocket and a plug cut to match	Pocket filled with tinted epoxy
Fit tolerance	Forgiving. The slopes self correct.	Unforgiving. Needs to be exact.	None needed at all
Detail possible	Very fine, including lettering	Limited by the corner radius of the bit	Any shape
Corners	Genuinely sharp	Rounded, unless you add relief cuts	Sharp, limited only by the pocket
Difficulty	Moderate, once you find your glue gap	High	Low to machine, moderate to finish
Best for	Lettering, logos, fine artwork	Simple geometric shapes	Colour, voids, cracks, river effects

V-carve inlay

The technique worth learning, because the geometry does the hard work for you. Both halves are cut with the same V-bit, so their walls slope at the same angle and the plug wedges into the pocket. A small size error just means the plug seats slightly higher or lower, and the visible joint still closes tight.

The full method, including the glue gap and what each setting does, is in V-carve inlay.

Flat inlay

A flat bottomed pocket and a plug cut to fill it. Conceptually simple and practically demanding, because a round tool cannot cut a sharp inside corner:

• The pocket has rounded corners. The plug must have matching rounded corners, or it will not seat.
• Cut the pocket inside the line and the plug outside the line, with a small allowance to tune the fit.
• Test on scrap. A few thousandths decides between a joint that will not close and one with a visible gap.
• Depth matters. The plug should sit slightly proud so you can flatten it flush after glue-up.

Resin inlay

Machine a pocket, fill it with tinted epoxy, let it cure, flatten it back. No fit problem at all, because the filler takes the pocket's shape exactly.

• Seal the pocket first in porous wood, or the resin wicks into the grain and leaves a halo.
• Overfill. Epoxy shrinks slightly and it settles into the grain, so fill proud and flatten after.
• Mind the bubbles. Warm the resin slightly, pour slowly, and pass a heat source over the surface briefly.
• Full cure before flattening, not just set. Green epoxy gums the cutter.
• Flattening is a mixed material cut. Wood and resin have very different hardness, so light passes and a sharp surfacing bit. See epoxy and composites.

Material pairing

• Contrast is the point. Walnut into maple, maple into walnut, or a light species into a dark one.
• Match density where you can. Very different hardnesses flatten unevenly.
• Mind wood movement. Two species moving at different rates across the grain can open a joint months later. See wood movement.
• Watch for bleed. Dark dust in light pores is a permanent grey halo. Blow the pocket out before glue-up and use a glue that matches rather than contrasts.