Before You Cut the Wood: A Simple, Precise Plan for Shelves and Cable Holes

A Small Project Still Has Irreversible Steps

Imagine three wooden shelves for a compact workstation. One holds a monitor, another a router and a small hub, and the third keeps chargers and accessories off the desk. Power and data cables need to pass neatly from one level to the next. The job sounds straightforward: cut three rectangles and drill a few circles.

The questions appear as soon as the tools come out. Are all three boards truly identical? Which edge is the back? Do the holes line up when the shelves are installed? Is there enough room for the largest plug, not only the cable? Will a hole collide with a bracket or screw underneath? A simple sketch can contain all the right numbers and still leave those relationships unclear.

This is a different problem from deciding where shelves belong in a room. If that is your current stage, start with our example of planning shelves in a tiny studio. Here, the room layout is already understood. The task is to turn each shelf board into an unambiguous part before wood is cut.

Start with the Cable Route, Not the Saw

First place the devices in the intended layout, even if only approximately. Mark the outlet or power strip, the equipment on each shelf, and the direction in which every cable needs to travel. This reveals whether each board needs a hole, whether the holes should align vertically, and where a gentle cable path is possible without crossing a support.

Measure the largest connector that must pass through the shelf. A USB cable may be narrow while its fixed plug is much wider. If you plan to fit a cable grommet, choose it before finalizing the circle: the visible outer diameter and the required cutout are not necessarily the same. Hardware suppliers such as Lee Valley list the hole dimension separately for this reason.

The correct diameter is therefore not a universal 60 or 80 mm. It is the cutout required by the chosen fitting, checked against the actual plugs, cable count, usable opening, and bend space for this project.

Give Every Board a Name and an Orientation

Label the parts Shelf A, Shelf B, and Shelf C. On each drawing, mark front, back, left, and right. Then choose two reference edges—usually the back and one side—and locate every hole centre from those same edges. Measuring to a circle's centre is clearer than measuring to its rim, and common reference edges prevent a correctly dimensioned hole from being mirrored onto the wrong side.

If only Shelves A and B need cable access, show no circle on Shelf C and write “no hole.” If one shelf is shallower or uses a different support, give it its own dimensions. Repetition should be explicit, not assumed.

Check the Hardware Around the Hole

Draw the bracket footprint, screw zones, wall clearance, and any equipment feet that sit on the shelf. Check the full grommet flange as well as the cutout. A circle can clear a screw centre and still leave no room for the fitting above it. On stacked shelves, verify the path in elevation too: aligned holes are useful only if cables can reach them without a connector, power brick, or support blocking the route.

This is where a drawing becomes more useful than a list. The same page shows the finished outline, hole centres, support exclusions, visible edges, and notes. Another person can understand which dimension belongs to which feature without reconstructing the project from messages.

Separate Finished Dimensions from the Cutting Plan

The part drawing should state the finished size of each shelf. The cutting layout has a different job: it must also account for the actual board or sheet, edge trimming, defects, grain direction, and the material removed by the blade. That removed width is the saw kerf. As Kreg's circular-saw guide explains, the cut belongs on the waste side of the line; placing the blade on the wrong side shortens the piece.

Do not quietly add a guessed kerf width to the finished dimension. Record the required finished part, then prepare the cut sequence using the actual kerf produced by the blade and setup. Label each piece immediately after cutting so its reference edges and visible face remain clear.

Test Once Before Repeating Three Times

Test the drill and grommet on an offcut of the same material. That small trial confirms the real fit and shows how the surface behaves before a finished shelf is at risk. For a cleaner exit face, WOOD Magazine recommends supporting the fibres with a clamped backing board, or drilling from both faces when a backer cannot be used.

Cut and drill one shelf first, then make a dry fit with the actual support, grommet, device, and largest connector. Only after that part matches the drawing should you transfer or repeat the layout on the others. A reusable drilling guide can improve consistency, but it does not replace checking each mark from the chosen reference edges.

A Final Check Before the Power Tools Start

• Are the quantity, finished length, depth, and actual material thickness recorded?
• Does every part show its front, back, left, right, visible face, and reference edges?
• Is each hole defined by a diameter and a centre measured from two fixed edges?
• Will the largest connector and the selected grommet fit the planned opening?
• Are brackets, screws, walls, devices, ventilation space, and the complete cable route clear?
• Does the cutting layout allow for the actual saw kerf and waste without changing finished sizes?
• Has one offcut and then one complete shelf been tested before repeating the work?

Where MilliDraw Fits

In MilliDraw, the shelf outline, circular cutouts, exact positions, and notes can stay together in one measured drawing on iPad. A dimensioned PDF gives you or a workshop a readable cutting reference. A DXF can carry the vector geometry into a controlled CAD workflow, but it is not an automatically approved CNC file, drilling template, nesting plan, or structural calculation.

The drawing does not need to be complex. It needs to make the important decisions visible before a saw or drill makes them permanent. For two or three shelves, that may take only a few minutes—and those minutes can protect the material, keep the holes aligned, and make the finished cable route look intentional.