Spoilboard Generator — CNCHelper.ca

Not sure what hole size?Cut a strip of test holes with the Insert Fit Test, find the one that grips, and send it back here.

Board

Units

Millimetres Inches

Width X Length Y Thickness

X0 Y0 is the board's front-left corner. Z0 is the top of the board. Surface it first with the Slab Flattener.

Hole grid

Cut a grid of holes

Pattern Placement Spacing X Spacing Y First hole X First hole Y Min. edge margin

Hole

Hole diameter Hole depth

Chips are rough starting points. Inserts grip differently in MDF, plywood and hardwood, so a fit test beats any chart. Make the hole about 1–2 mm deeper than the insert is long.

Drill all the way throughFor bolting the board down to T-nuts or inserts in a base below. Cuts slightly into whatever is under the board. Break-through Counterbore each holeA wider, shallow pocket on top so the insert flange (or a bolt head) sits below the surface, and you can resurface without hitting brass.

Counterbore Ø Counterbore depth

Skip holes that would hit a slot

T-track & slots

Dado = a square groove for store-bought aluminium T-track. T-slot = a custom T-track cut right into the board with a keyhole or T-slot cutter.

Dado size (all dados)

Dado width Dado depth

Measure your track. Most is ¾″ wide by ⅜″ deep (about 19 × 9.5 mm). Cut a short test piece first: a snug track shouldn't need forcing.

T-slot shape (all T-slots)

Neck width (top opening) Lip thickness

The neck lets the bolt through. The lip is the wood left above the undercut, and it holds the bolt head down. Undercut size comes from the cutter in Tools.

Cut the neck first with the main bitNeeded for T-slot cutters. With a keyhole bit, leave it off and the bit's own neck cuts the opening. Drill an entry hole for the cutterFor slots that stop inside the board. The cutter drops into this hole, runs the slot, and comes back out the same way.

Engraving

Ruler marks along the edges

Front edge Back edge Left edge Right edge

Ruler units Tick every Number everyticks Short tick Long tick Edge inset

Measure from Number height

Engrave numbers on the long ticks

Hole labels & lines

Hole labels Label height Grid lines Gap around holes

Centre linesOne line across X and one across Y through the middle of the board. Handy for centring work.

Your own labels

Add text anywhere: zone names, "HOLD-DOWN ONLY", the date. Or pick Place label above the preview and click the board.

New label text Height

Tools

1 · Main bit (holes, dados, necks)

Diameter Depth / pass Stepover% Feed Plunge SpindleRPM

Hole direction

Holes bigger than the bit are cut with a helix (circular ramp), so one bit makes any size. A hole the same size as the bit is pecked straight down. Use a centre-cutting end mill.

2 · Engraving bit

Type V angle° Tip width Diameter Depth Feed Plunge SpindleRPM

3 · Keyhole / T-slot cutter

Head Ø Head height Neck / shank Ø Feed SpindleRPM

These cutters take a full-width bite with no way to step down, so go slow: about a third of your normal feed. Z zero is the bottom of the head.

Machine & output

Safe height Travel height Spin-up waitsec Rapid speed

Safe height is used at the start, end and tool changes. Travel height is for hops between holes and strokes, so keep it above any screw heads or clamps. Rapid speed is only for the time estimate.

Tool changes Return to X0 Y0 at the end

Toggle holes Place label Toolpaths

Hover the board

Holes

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Slots

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Engraving

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Est. run time

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Tools

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Air-cut G-codeLifts every Z so the bit never touches the board.

Before you cut

Show the G-code