Bantam Tools Desktop PCB Milling Machine: Complete Setup Guide for Isolation-Routed PCBs

Most of the PCB milling content on this site — the FlatCAM workflow, double-sided board registration, auto-leveling and probing — assumes you're adapting a general-purpose router like the Wolfpawn to the job. The Bantam Tools Desktop PCB Milling Machine is built to do exactly one thing well: mill circuit boards, with nothing else competing for its rigidity, software workflow, or spindle characteristics. If you prototype boards often enough that setup time matters, this is the machine that removes PCB milling from your general CNC's job list entirely. Here's how to get it running.

What Makes This Machine Different

SpecValue Work area140 × 116 × 31mm Spindle250W, up to 28,000 RPM ControllerBantam Tools Software (grbl-based) ConnectionUSB Primary usePCB isolation milling, small precision parts

The high-RPM 250W spindle is the headline spec that matters for PCB work: milling copper cleanly with the tiny end mills and V-bits PCB isolation routing requires (often 10 mil or smaller) needs spindle speed, not torque, and 28,000 RPM keeps chip load reasonable without the tool digging in or tearing copper. A router-class machine spinning a trim router at 10,000-16,000 RPM with a collet not designed for sub-1mm tooling will chatter and break bits far more often on the same job.

Unboxing and Bed Setup

The machine ships assembled and calibrated from the factory — there's no gantry squaring or belt tensioning step like you'd do on a kit router. Unbox it onto a stable, vibration-free surface, connect USB, and install the Bantam Tools software, which handles both the milling workflow and firmware updates. Home the machine on first power-up and verify the spindle spins freely with no rubbing before loading a bit.

Secure your copper-clad blank to the bed using the included clamps, double-sided tape, or a sacrificial spoilboard with screws around the perimeter — anything that keeps the blank dead flat. Because isolation routing traces can be a few thousandths of an inch wide, even slight blank flex or lift at a corner will produce a trace that's cut too deep in one spot and not cut through in another.

Software Workflow: Gerbers to G-Code

Bantam Tools' own software accepts Gerber files directly and generates isolation, drill, and outline toolpaths without needing a separate CAM step — this is the main workflow advantage over a general CNC, where you'd typically go through FlatCAM or a similar tool first. Export Gerbers and an Excellon drill file from KiCad, Eagle, or your CAD tool of choice, import them, and the software walks you through tool selection (typically a 10-mil or 20-mil V-bit for isolation, a 1/32" end mill for outline cuts, and appropriately sized drill bits for through-holes) and depth-of-cut settings per layer.

If you prefer FlatCAM's more granular control over toolpath generation, that workflow still works here — export standard G-code from FlatCAM and load it through Bantam Tools software as a raw job rather than using the built-in Gerber import. Either path lands on the same machine control layer.

Z-Probing and Surface Mapping

Copper-clad board is rarely perfectly flat, and isolation cuts are shallow enough (often 0.1-0.2mm deep) that even minor Z variation across the board ruins a trace. Run the machine's auto-touch-off / surface probing routine before every job rather than trusting a single Z-zero point — it maps the actual surface height across your work area and adjusts cut depth in real time. Skipping this step is the single most common cause of a job that mills perfectly on one side of the board and fails to cut through on the other.

Double-Sided Boards

For double-sided work, mill the first side, then flip the board around a fixed registration pin or dowel pair mounted in the spoilboard so the second side aligns to the first within a few thousandths of an inch — the same registration approach covered in our double-sided PCB milling guide applies directly here, just at a smaller physical scale given the machine's 140×116mm bed.

Tool Care and Bit Selection

PCB engraving bits (conical V-bits with a small flat tip) are consumable and dull faster than most makers expect, especially milling through FR4's fiberglass weave rather than plain copper foil. Keep spares on hand, and replace a bit at the first sign of a trace that looks "torn" rather than cleanly cut rather than pushing a dull bit through more boards. Clear the bed of copper dust between jobs — it's conductive and can bridge fine traces if it settles into a freshly milled board.

Safety Notes

FR4 dust contains fine fiberglass particulate that irritates skin and lungs — vacuum rather than blow it off the bed, and wear a dust mask during cleanup on any session with more than a board or two milled. The high-RPM spindle at 28,000 RPM is unforgiving of loose clothing, hair, or jewelry near the work area; treat it with the same respect you'd give a router spindle even though its physical size is small.

For anyone milling more than the occasional prototype board, a dedicated machine like this pays for itself in setup time saved and traces that come out clean on the first pass rather than the third. It won't do sign work or cabinet parts, but that was never the job — for PCBs specifically, it's a more direct path from Gerber file to working board than adapting a general-purpose router ever will be.