PCB Tooling Holes Explained: Placement, Sizes & Design Rules for Manufacturing

I’ve seen too many PCB designs come back from the fab house with angry emails about missing or incorrectly placed tooling holes. After 10+ years in the industry, I can tell you this: these tiny holes might seem insignificant, but they can make or break your manufacturing run.

PCB tooling holes are small, non-plated circular openings that serve as reference points during fabrication and assembly. They keep your board stable during drilling, help align stencils for solder paste application, and guide pick-and-place machines during component placement. Without them, you’re essentially asking the machine to hit a moving target.

In this guide, I’ll walk you through everything you need to know about PCB tooling holes—from proper sizing and placement to manufacturer-specific requirements and common pitfalls I’ve learned to avoid the hard way.

What Are PCB Tooling Holes and Why Do They Matter?

PCB tooling holes are pre-drilled, non-plated through-holes that secure and align your circuit board throughout the manufacturing process. Think of them as anchor points—pins or fixtures slot into these holes to hold your PCB perfectly still.

During fabrication, your board needs to stay precisely aligned for drilling operations. A shift of even 0.1mm can result in vias missing their target pads entirely. When your board moves to assembly, the same tooling holes help the pick-and-place machine know exactly where every component should land.

Here’s where tooling holes come into play during manufacturing:

The key thing to remember: tooling holes are typically placed on the panel or breakaway rails, not on the individual PCB itself. Your fab house produces panels, not single boards—so the tooling holes belong in the panel area.

PCB Tooling Holes vs. Mounting Holes vs. Fiducial Markers

I see engineers confuse these three features all the time. Let me clear this up once and for all:

Tooling holes are temporary—they exist only during pcb manufacturing. Once the panel is depanelized, they’re gone with the breakaway rails.

Mounting holes are permanent. They’re part of your finished product and let you screw the PCB into an enclosure or attach standoffs.

Fiducial markers aren’t holes at all—they’re exposed copper circles that optical systems use to calibrate component placement. You need both fiducials AND tooling holes for proper SMT assembly.

Standard PCB Tooling Hole Sizes

Most manufacturers accept the following standard tooling hole diameters:

Pro tip: Stick with one consistent size for all tooling holes on your panel. Mixing sizes creates problems with tooling fixtures and increases the chance of assembly errors.

For JLCPCB specifically, their assembly service requires:

• Diameter: 1.152mm (45.4 mil)
• Type: Non-plated through-hole (NPTH)
• Solder mask expansion: 0.148mm

If you’re using PCBWay or other manufacturers, 2.0mm non-plated holes are typically the standard.

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Where to Place PCB Tooling Holes

Placement matters just as much as size. Here are the rules I follow:

The Basics

1. Use 2-3 tooling holes minimum — Two holes define X/Y positioning; a third prevents rotation errors
2. Place them in opposite corners — This maximizes the distance between reference points for better accuracy
3. Put them on breakaway rails — Not on the PCB itself, unless you’re doing single-board production
4. Maintain asymmetry — One hole should be offset to indicate board orientation (prevents reverse mounting)

Distance Guidelines

Panel Layout Example

For a standard panel with breakaway rails:

  ○                              ○  ┌──────────────────────────────┐  │    ┌────────┐  ┌────────┐    │  ← Breakaway rail  │    │  PCB   │  │  PCB   │    │  │    │   1    │  │   2    │    │  │    └────────┘  └────────┘    │  │    ┌────────┐  ┌────────┐    │  │    │  PCB   │  │  PCB   │    │  │    │   3    │  │   4    │    │  │    └────────┘  └────────┘    │  └──────────────────────────────┘  ○                                   ↑ Offset for orientation

The three holes form an “L” pattern. Notice the bottom-left hole is offset—this tells the assembly machine which way is “up.”

PCB Tooling Hole Design Specifications

Getting the specifications right prevents manufacturing delays. Here’s what you need to nail:

Plating Requirements

Always use non-plated (NPTH) holes for tooling. Here’s why:

• Non-plated holes have tighter dimensional accuracy
• Plating adds copper that can vary in thickness
• Plated holes may not fit standard tooling pins
• Cost savings—no extra plating step required

Solder Mask Considerations

Your solder mask opening should be larger than the hole diameter. This prevents:

• Solder mask from partially covering the hole
• Debris accumulation around the hole edge
• Interference with tooling pins

A solder mask expansion of 0.1mm – 0.15mm around the hole works well.

Multi-Layer PCB Requirements

For multi-layer boards, you need isolation rings on inner negative layers. Without these, your tooling holes might accidentally connect to power or ground planes.

The isolation ring should be at least 0.3mm (12 mil) larger than the hole diameter.

How to Add PCB Tooling Holes in Popular Design Tools

Here’s how to create tooling holes in the CAD software you’re likely using:

KiCad

1. Open the PCB editor
2. Go to Place → Add a Footprint
3. Search for “MountingHole” in the library
4. Select a non-plated version (NPTH)
5. Set the hole size in footprint properties
6. Place on your panel rails

Alternatively, create a custom footprint:

• Create a new footprint
• Add a pad with Pad Type = NPTH (Non-Plated Through-Hole)
• Set hole size to your required diameter
• Set pad size equal to or smaller than hole size (no copper ring)

Altium Designer

1. Go to Place → Pad
2. In the pad properties, set:
   1. Hole Size: Your required diameter (e.g., 2.0mm)
   1. Plated: Unchecked (non-plated)
   1. X-Size/Y-Size: Same as hole size or smaller
3. Place at your desired locations

Eagle

1. Switch to the Dimension layer
2. Use Draw → Hole command
3. Set the drill diameter
4. For NPTH, ensure no copper is around the hole
5. Place in corner positions

EasyEDA

1. Go to Place → Pad
2. In properties, set:
   1. Hole Size: Required diameter
   1. Shape: Round
   1. Type: NPTH
3. Leave pad size equal to hole size (no copper)

Common PCB Tooling Hole Mistakes to Avoid

After reviewing hundreds of designs, these are the mistakes I see most often:

1. Placing Tooling Holes on Traces or Copper Pours

This creates a short circuit or damages your routing. Always check that your tooling hole locations have adequate clearance from any copper features.

Fix: Run a DRC check and ensure minimum 3mm clearance from all copper.

2. Using Plated Holes Instead of NPTH

Plated holes have looser tolerances and won’t fit standard tooling pins properly.

Fix: Double-check your drill file. Tooling holes should appear in your NPTH drill output, not your PTH drill output.

3. Wrong Size for Your Manufacturer

Each assembly house has different equipment. What works for one may not work for another.

Fix: Always check your manufacturer’s requirements before finalizing your design. JLCPCB wants 1.152mm; others want 2.0mm.

4. Forgetting Inner Layer Isolation

On multi-layer boards, your tooling holes can accidentally connect to power or ground planes.

Fix: Add isolation rings (anti-pads) on all inner negative layers, at least 0.3mm larger than the hole.

5. Placing Holes Too Close to the Board Edge

This weakens the panel structure and can cause cracking during depanelization.

Fix: Maintain at least 3-5mm distance from the PCB edge and panel outline.

6. Inconsistent Hole Sizes

Using different sizes across your panel creates tooling problems.

Fix: Standardize on one size for all tooling holes on a given panel.

7. Not Adding Enough Holes

Two holes minimum, but three is better for preventing rotation errors.

Fix: Use an asymmetric three-hole pattern for foolproof orientation.

Manufacturer-Specific PCB Tooling Hole Requirements

Different manufacturers have different standards. Here’s a quick reference:

Important: When in doubt, let your manufacturer add the tooling holes. Most fabs offer this as a standard service (sometimes at a small additional cost). They know exactly what their equipment requires.

Useful Resources and Downloads

Here are some resources I recommend bookmarking:

Manufacturer Guidelines

• JLCPCB Tooling Holes Guide — Official specifications for JLCPCB assembly
• PCBWay Panelization Guidelines — Complete panel design instructions
• Eurocircuits PCB Design Guidelines — Detailed drilling specifications

KiCad Libraries

• KiCad Official Mounting Hole Library — Includes NPTH tooling hole footprints
• Search for “MountingHole_*mm_Pad” in your KiCad footprint library

IPC Standards

• IPC-7351B — SMD footprint and land pattern guidelines (includes mounting hole requirements)
• IPC-2221 — General PCB design standard with hole specifications

Design Calculators

• Saturn PCB Design Toolkit — Free calculator for PCB specifications
• JLCPCB DFM Analysis — Free design-for-manufacturing check on upload

FAQs About PCB Tooling Holes

How many tooling holes do I need on my PCB?

A minimum of two tooling holes is required for basic X/Y alignment. However, I strongly recommend three holes arranged in an asymmetric “L” pattern. The third hole prevents the board from being loaded backwards (rotated 180°). For larger panels (over 300mm), consider adding a fourth hole for additional stability.

What is the difference between tooling holes and via holes?

Vias are small, plated holes that provide electrical connections between PCB layers—they’re part of your circuit. Tooling holes are larger, non-plated holes used purely for mechanical alignment during manufacturing. Vias carry current; tooling holes hold your board in place. Never confuse the two in your drill files, or you’ll have serious problems.

Can I use existing mounting holes as tooling holes?

Sometimes, but it’s not ideal. Mounting holes are designed for your final product assembly and may be plated for grounding purposes. Tooling holes should be non-plated for accuracy and are typically located on breakaway rails that get removed after manufacturing. If your board has no rails and you’re doing single-unit production, your manufacturer might use mounting holes as tooling references—but check with them first.

Do I need tooling holes if I’m only ordering bare PCBs (no assembly)?

For fabrication-only orders, tooling holes are less critical since you’re not running through pick-and-place machines. However, they still help during drilling and testing. Many manufacturers will add their own tooling to the panel for fabrication. If you’re ordering assembly services (PCBA), tooling holes are essential.

My manufacturer says they’ll add tooling holes automatically. Should I still include them in my design?

It depends on your needs. If you let the manufacturer add them, you have less control over placement—they might end up in inconvenient spots or add breakaway rails you didn’t plan for. If you’re space-constrained or have specific fixture requirements, add your own tooling holes in the locations you want. Most manufacturers accept customer-placed tooling holes as long as they meet their specifications.

Wrapping Up

PCB tooling holes might be the most overlooked feature in board design, but getting them right can save you weeks of manufacturing delays and costly rework. Remember the key points:

• Use non-plated holes (NPTH) at standard sizes (1.0mm, 1.5mm, or 2.0mm)
• Place them on breakaway rails, not on your finished board
• Use three holes in an asymmetric pattern for proper alignment and orientation
• Check your manufacturer’s requirements before finalizing—JLCPCB wants 1.152mm, others may differ
• Maintain adequate clearance from copper, traces, and the board edge (minimum 3-5mm)

Take five minutes to verify your tooling holes before you hit “Order.” Your manufacturing team—and your schedule—will thank you.