These PCBs were made with the desktop CNC from Bantam Tools. The otherplan software because you can easily drag and drop your cad files. We designed the PCB in Autodesk Eagle and created a custom footprint for the QT Py. This was routed for a single-layered board and features pretty chunky traces.

FR-1 Single-sided PCBs

These singled-sided FR-1 blanks from bantam tools are pre-cut so they fit on the spoilboard.

Double-sided Tape

To secure the PCB blank to the spoilboard, you can use double-sided scotch tape. I like to use wide tape because it gives you more coverage – just be careful the tape doesn’t overlap.

Secure to Spoilboard

The PCB is lined up with the lower left corner of the spoilboard. Material can be warped so I make sure to press down firmly and wipe the surface clean.

Endmill with the Fan Bit

The 1/32 inch flat end mill is my go-to tool whenever I’m milling PCBs. Using a fan bit keeps the dust away and it’s handy if you’re doing any sort of filming.

End mills are secured to the collet and the machine has a probing process that checks the tool z-height.


Four QT Py Heart PCBs fit on one sheet of FR-1 (127mm x 101mm). You can get the most out of your material by placing your boards closer together.

Start Milling

After going through your internal checklist, "Get Ready to Start Milling!"

Remove PCBs

Use alcohol to soften up the adhesive from the tape. A squirt bottle is great for applying to the spoilboard.

Use a thin spatula or palette knife to pry the FR-1 sheet off the spoilboard. Ideally remove the whole PCB from the spoilboard in one piece.

Clean PCBs

Wipe the PCBs clean with alcohol using paper towels. Use Scotch Brite scuff pads to lightly sand the edges and surface.

Finished PCBs

After some clean up, the PCB’s came out really nice. All four of these came out pretty clean, so we can get them ready for soldering. They only took about 10 minutes to machine, which is pretty impressive.

This guide was first published on Feb 09, 2021. It was last updated on Feb 09, 2021.

This page (Milling PCBs) was last updated on Feb 04, 2021.

Text editor powered by tinymce.