LUNYEE 3018 MDF Spoilboard

LUNYEE sized it for its own two 500W machines, and three details set it apart from a plain offcut of MDF:

• 24 M6 holes spread across the board, with no two neighbours more than 54 mm apart, so a small clamp always has a hole close to the edge of the stock.
• A printed centimetre grid on the face, which makes squaring a blank or centring a coaster quick without a ruler.
• Two sets of mounting parts, because the Pro Max and Pro Ultra tables are built differently.

The Pro Max uses a T-slot style bed, while the Pro Ultra has a one-piece machined aluminium plate with its own scale. Either one is expensive to replace and slow to re-flatten. A board that costs a fraction of that takes the damage instead.

MDF suits the job because it is even all the way through. There is no grain to tear out, no knots and no voids, so a surfacing pass leaves a uniform face. It is also soft enough that a stray plunge only marks the board and the bit survives.

The cure is a surfacing pass: skim the whole board with a wide flat bit so its face matches the gantry exactly. On a 500W spindle a 1/4-inch or wider flat bit works, cutting 0.2 to 0.3 mm deep with generous stepover.

1. Screw the board down with the supplied hardware and check that nothing rocks.
2. Zero Z on the highest point of the board.
3. Run a pocket across the whole area at 0.2 to 0.3 mm deep.
4. Vacuum the dust and repeat only if the pass left untouched patches.

There is a trade-off here. The printed grid lives on the surface, and a full surfacing pass removes it. Two approaches keep both benefits:

• Surface only the area you cut in most, and keep the grid at the edges for squaring stock.
• Leave the board untouched until the first real scars appear, then surface and redraw a few reference lines by engraving them with a V-bit.

For the coasters themselves, a through-cut should go 0.2 to 0.5 mm into the board so the last skin of walnut parts cleanly. Small tabs hold each disc in place until the job finishes, and a light sanding removes them afterwards. The board takes those shallow grooves job after job before it needs another skim.

With neighbours under 54 mm apart, there is almost always a hole within reach of any edge. That makes small side clamps practical, and LUNYEE makes two that suit its own machines: tiger claw side clamps with serrated faces, and mini hold-down clamps for stock up to 1.77 inches thick.

How to hold three common materials:

• Cast acrylic sheet: side clamps on two edges, plus masking tape and a thin line of superglue under the middle if the sheet is thin and likely to lift.
• Hardwood blanks: side clamps on opposite corners, snug but not tight enough to crush the edge.
• 6061 aluminium plate: clamp on three sides and keep passes shallow. MDF gives a little under pressure, so an aluminium job wants lighter cuts than on a bare metal bed.

MDF does have one weakness. Water, oil and coolant soak into the fibres and swell the board, so any aluminium work should run dry or with an air blast. A few drops of lubricant on the bit are fine; puddles are not.

The M6 holes also take jigs. A plywood fence screwed into two holes gives a square corner for batch work, like a run of identical name tags, and it comes off in a minute when the job ends.

Worn threads are the usual end of an MDF board. M6 screws driven straight into fibreboard strip if they are tightened hard or swapped in and out every day. Snug is enough; if a hole goes soft, move the clamp to its neighbour, which on this grid is never far away.

Pick the LUNYEE board if you own one of its two machines and want the mounting to line up without drilling. Pick a Genmitsu or Doesbot board if the frame is a Genmitsu 3018-PRO or a generic open-frame kit. The vacuum table is a different tool: no clamps at all, good for thin sheet, but it cannot take through-cuts the way sacrificial MDF can.

Three measurements settle the fit:

1. That the frame is a LUNYEE Pro Max or Pro Ultra, or that your table's hole pattern matches the board.
2. The table's real footprint, given the two sets of dimensions LUNYEE prints.
3. That 12 mm of lost Z height still leaves room for your thickest stock and longest bit. On the 80 mm Z of these machines, it usually does.

Cost per scar also counts for it. A board this size is cheap enough to treat as a consumable, and once it is thin from repeated surfacing, a new one drops into the same holes.

For the machines themselves, see the Pro Ultra logbook and the Pro Max comparison.