Drilling small holes and drilling paths

For a new design, I need to drill small holes. Using the smallest bits I can mount on the CNC, it’s difficult to go below 4mm (a 3mm drill bit with a circular or bore path).

Fusion 360 can generate drilling paths, which would appear to fit the bill (not sure yet), but I’m struggling with how to mount drills to the Makita router. Drill typically have the same diameter throughout so the smallest drill I can mount is… 6mm.

I have seen products like these drill adapters from Amana but I’m not sure that I understand how it works. Clearly if I mount the drill bit in the adapter… it won’t be centered :face_with_head_bandage:


Am I supposed to use them with a reducing bushes? And get a whole collection of bushes suitable for the different drill bits?

Alternatively would there be an option to mount a drill chuck safely on the Makita router?

Thanks for any guidance/help.

I don’t see any reason why you couldn’t use a ‘Drill Adaptor’. From the looks of it, you could use an inner sleeve with a diameter the same as the end mill/drill bit you choose to use, securing it with the grub screws.

You could get an 1/8" collet and use the small square plunge bits from Bits & Bits. Not a drilling operation, but milling your small holes. Winston Moy did a video on drilling with the cnc routers on his youtube channel. Keep us posted on your progress/project!

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Generally when you start compiling adapters/adapter bushings it’s not a good outcome. What I usually do in small drill situations is exactly what @gpkon66 Gary mentioned. I plunge the hole for location with a smaller end mill, then open the hole up if required on a secondary operation (such as on a drill press). You can find small chucks that you could use in the Makita, but unfortunately the vast majority of them have 1/4" hex shanks.

This part for example, had 2 #4-40 tapped holes and 2 0.062 holes. I plunged location with a 1mm end mill and finished up the operation on my mill.

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I agree that stacking adapters/bushings is a bad idea. It can be done, just not the best practice in my opinion…

I’m not sure how cost effective it would be, but you could use a “circuit board drill bit” depending on the depth you needed to drill. These come with 1/8" diameter shanks.




Thanks for the replies.

I understand that stacking adapters is not an ideal solution. Plus having watched the video from Winston Moy, it answers many of questions on using drill bits with the CNC. RPM of the router, indeed.

Thanks for pointing me to Bits & Bits and the 1/8". I’m in Europe and I’ll need to find a local alternative, ideally metrics as well, to keep shipping and tax costs in control. It’s interesting that Ellaire manufactures a 4mm collet for the Makita.

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Looking for routing bits, in metrics I have found the Fraiser microbits but with a 3mm shank. Ooznest has 3mm collet for the Makita but, since Brexit, that’s an import :frowning_face:

Of course they are pretty short bits so only good to pre-drill holes that I will need to finish with a cordless drill.

In imperial bits, there’s also the Amana 1/16" diameter “long” bits with a 1/4" shank which I had somehow missed. Those bits are longer but still only good to pre-drill.