Building a Simple Fixture Plate for Repeat CNC Jobs

A fixture plate lets you repeat the same job without re-zeroing every time. Essential for the 200-peak project or any batch run.

Concept

A fixture plate is a sacrificial board with:

• A fixed work zero reference (corner or center)
• Indexing pins, ledges, or machined pockets to locate each workpiece consistently
• The same X/Y/Z zero used every time

Making a Basic Fence Fixture

The simplest fixture: two straight edges at 90° screwed to the spoilboard.

1. Mill a perfectly square corner into an MDF waste sheet using the CNC itself
2. Screw two straight strips of MDF along the X and Y axes
3. Butt your stock into the corner for every piece
4. Re-zero Z only — X/Y stays the same

This eliminates re-zeroing X and Y between sheets.

Making a Pin Fixture

For parts with a hole or slot you can use for registration:

1. Machine a hole pattern into your fixture plate (CNC-drilled for accuracy)
2. Press steel dowel pins into the holes
3. Design matching holes into your workpiece CAD
4. Drop workpiece onto pins — perfectly located every time

The 200-Peaks Fixture Approach

For the peak project:

1. Mark a fixed corner on the spoilboard in permanent marker
2. Always place sheet to that corner (add a fence strip if needed)
3. Re-zero Z per sheet (thickness varies), leave X/Y alone
4. Run the nested toolpath — same file every sheet

With a consistent fence, 30 seconds per sheet setup instead of 3 minutes.

Material for Fixture Plates

• MDF — cheap, easy to machine, flat, disposes easily
• HDPE — durable, reusable many times, dimensionally stable
• Aluminum — most accurate, reusable indefinitely, overkill for wood work

Replace MDF fixture when it gets cut into too many times or warps.