Layout for Joinery and Hardware: Holes, Dadoes, Mortises, and Hinges

Mini-Module 1: Holes (Centered, Spaced, and Ready to Drill)

Reference selection

Choose a single reference face and a single reference edge for the part, then keep every hole location tied to those references. For a panel, that might be the “show face” and the bottom edge; for a rail, it might be the face that registers against a fence and the edge that registers against a stop. The goal is that if the part is flipped or rotated later, you still know exactly which surfaces your layout came from.

Layout method

Centering a hole on a width is best done by direct bisecting rather than arithmetic when possible. If you must compute, mark lightly, then refine with a knife line or a sharp pencil line depending on whether the hole will be hidden or visible.

• Method A (bisect with dividers): Set dividers to a span slightly more than half the width. From each edge, strike arcs that cross; connect the intersection points to locate the centerline. This avoids reading errors and works even if the width is slightly off nominal.
• Method B (center-finding jig/block): Use a shop-made center finder for repeated parts (e.g., dowel holes in multiple rails). Register the jig to the same edge each time.

Spacing a row of holes (shelf pins, hardware screws, dog holes) is most reliable when you establish two “end conditions” first, then fill the spacing between them.

• Mark the first hole location from your reference edge/face.
• Mark the last hole location from the same reference system (not from the first hole).
• Use a template, indexing jig, or setup block to step the intermediate holes so spacing doesn’t drift.

Starting holes accurately: After the intersection is located, use an awl or center punch to create a positive drill start. For small bits and hardwood, a sharp awl is often enough; for larger bits or metal hardware plates, a center punch gives a deeper, more durable dimple. Keep the punch vertical; a tilted punch shifts the bit start.

Verification step

• Visual alignment: Sight down the row of punched marks under raking light; mis-spaced marks often “wave” visually even before measuring.
• Diagonal check for rectangular patterns: If laying out four holes in a rectangle (e.g., bracket), measure diagonals between opposite holes; equal diagonals indicate a true rectangle.
• Hardware overlay: Place the actual hardware (or a paper/acetate template) over the punched marks to confirm the pattern matches reality before drilling.

Test on scrap routine

Before drilling the real part, run a full drill-and-fit test on scrap of the same thickness.

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1. Transfer the same reference edges onto the scrap (mark them clearly).
2. Lay out and punch the hole locations using the same method and any jigs/setup blocks.
3. Drill with the same bit, at the same speed and backing support you’ll use on the real part.
4. Test-fit the fastener/dowel/bolt. Confirm: the hole is centered, spacing matches the mating part, and the fastener seats without forcing.
5. If anything is off, adjust the jig/setup block now (not the workpiece later).

Mini-Module 2: Dadoes (Accurate Locations and Clean Shoulders)

Reference selection

Dado location must be referenced from the same face that will be visible or that will register during assembly. For casework, that’s typically the inside face of the cabinet side. Also decide which edge is “bottom” so every dado is measured in the same direction (this matters when parts are similar but not identical).

Layout method

Define dado walls with a knife wall for crisp shoulders and to prevent tear-out at the edges. A knife wall is especially valuable when the dado will be visible or when you’re using a router plane, chisel, or saw to establish the boundary.

1. Mark the first wall: Locate the dado position from the reference edge/face and strike a line. Deepen it with a marking knife to create a clear boundary.
2. Mark the second wall by direct transfer: Use the actual shelf/partition (or a setup block equal to its thickness) to mark the opposite wall. This captures real thickness and avoids “nominal” errors.
3. Square the lines across the face: Carry both knife lines across the width where the dado will be cut. If the dado stops, mark the stop line clearly and knife it as well.
4. Waste identification: Shade the waste area between the knife walls so you don’t accidentally cut on the wrong side.

Optional: define a shallow shoulder first. If you’ll cut the dado with a router, you can score the knife wall and then take a very light first pass to “set” the edge before full-depth passes. This reduces edge chipping.

Verification step

• Width check: Place the mating piece on the layout; it should land exactly between the knife walls without forcing or slop.
• Location check: If the dado aligns with another feature (e.g., a face frame rail), dry-assemble the parts and confirm the dado position supports the intended reveal/offset.
• Parallelism check: Measure from a consistent reference edge to each knife wall at two points; the readings should match, confirming the dado isn’t skewed.

Test on scrap routine

1. Use scrap of the same material and thickness as the real part.
2. Lay out the dado with the same knife-wall method and the same transfer piece/setup block.
3. Cut the dado using the intended tool setup (table saw, router, or hand tools) and the same depth setting.
4. Test-fit the mating piece. Confirm: it seats to depth, shoulders are crisp, and the fit is appropriate for glue (snug but not crushing fibers).
5. If using a router/table saw setup, lock in the settings only after the scrap fit is correct.

Mini-Module 3: Mortises (and Tenon Shoulders That Actually Close)

Reference selection

Mortise-and-tenon accuracy depends on consistent referencing between the mortised piece and the tenoned piece. Choose the face that will be flush in the final assembly (often the show face) and reference both mortise and tenon layout from that face. Also choose a reference edge for lengthwise positioning so shoulders land where intended.

Layout method

Mortise placement: Establish the mortise’s length (along the rail direction) and its position from the reference edge. Then establish its width (across the thickness) so the tenon will be centered or offset as designed.

1. Mark mortise ends: Locate the mortise start and stop positions from the reference edge and knife these end lines square across the face. These end lines define the shoulders of the tenon indirectly, so make them crisp.
2. Mark mortise sides: Use a mortise gauge (or equivalent two-line marking method) set to the chisel/bit width. Register the gauge from the reference face so the mortise is consistently placed.
3. Create knife walls at the ends: Deepen the end lines with a knife wall. This helps prevent the chisel from bruising past the boundary and gives a clean shoulder line when the joint closes.
4. Transfer to the mating tenon: Use the mortised piece as the master when possible: align reference faces, then transfer shoulder locations directly so the tenon shoulders match the real mortise position.

Tenon shoulders: Even if the cheeks are cut perfectly, gaps usually come from shoulders that aren’t square or that were laid out from inconsistent references. Knife the shoulder lines and treat them as “do not cross” boundaries.

Verification step

• Shoulder squareness: Check that shoulder lines are square to the reference edge on all faces that will show. A tiny angle error becomes a visible gap.
• Reveal check: If the joint must align with a face (e.g., flush frame), place the parts together without cutting and confirm the gauge lines will produce the intended flushness.
• Depth and haunch considerations: Confirm mortise depth leaves adequate material at the far side and that any haunch/shoulder details won’t collide with grooves or panel slots.

Test on scrap routine

Mortise-and-tenon is worth a full mock-up because small layout differences compound during fitting.

1. Prepare scrap pieces that match the real stock thickness and approximate width.
2. Lay out the mortise with the same gauge setting and the same reference face.
3. Cut the mortise using your intended method (chisel, mortiser, router).
4. Lay out the tenon by transferring shoulder locations from the mortised scrap (or from the same reference measurements) and cut it.
5. Test-fit. Confirm: shoulders close without gaps, the joint seats to depth, and the tenon isn’t forcing the mortise walls apart.
6. If the fit is too tight, adjust the cutting method (not the layout). If alignment is off, fix the reference strategy before touching real parts.

Mini-Module 4: Hinges (Repeatable Placement and Predictable Gaps)

Reference selection

Hinge layout must be referenced from the surfaces that control the door’s final position: typically the cabinet’s front edge (or face frame) and the door’s show face and top/bottom edges. Decide which edges define the reveal (gap) and keep all hinge measurements tied to those edges. For paired doors, reference both doors from their top edges so hinge heights match.

Layout method

Use templates or setup blocks to make hinge placement repeatable. A setup block can capture the distance from the top of the door to the top of the hinge leaf, and another can capture the setback from the edge. A template can also guide a router for mortising hinge gains.

1. Establish hinge height locations: From the top (and bottom) reference edge, mark hinge positions using a setup block or story template so both door and carcass match.
2. Mark the hinge leaf outline: Place the hinge on the workpiece aligned to the reference edge and height marks. Knife the perimeter lightly, then deepen the line where the shoulder must be crisp (the edge at the door/case corner is most critical).
3. Mark screw centers: With the hinge held in its knifed outline, use an awl to mark each screw hole center. This prevents the bit from wandering and keeps the hinge from “walking” during installation.
4. Gain depth control: If mortising a hinge leaf, use a depth stop (router, chisel gauge block, or measured chisel paring) so the leaf sits flush. Too deep creates a gap; too shallow prevents closing.

Repeatability tip: If you have multiple doors, do not measure each one independently. Use the same setup blocks/template and the same reference edges, and process all doors in the same orientation to avoid mirrored errors.

Verification step

• Dry placement: Tape or clamp the hinge in position and close the door against the opening (without screws) to confirm the hinge location supports the intended reveal and swing.
• Leaf flushness: Place a straightedge across the hinge area; the leaf should be flush with the surface. Any proud or recessed leaf changes the door position.
• Screw alignment: Confirm awl marks are centered in the hinge holes; off-center starts can pull the hinge sideways as screws tighten.

Test on scrap routine

1. Use scrap that matches the door and carcass thickness (two pieces if needed).
2. Lay out hinge position using the same setup blocks/template and reference edges.
3. Knife the outline, mark screw centers with an awl, and drill pilot holes using the same bit size and depth control you’ll use later.
4. Install the hinge on the scrap and test the action: does it bind, does it sit flush, do the screws pull it out of position?
5. Adjust pilot hole size, countersink, or template registration until the hinge installs cleanly and repeatably.