M2 Screw Countersink bit

I need to machine some countersinks in an aluminum part to accept a M2 tapered screw. Does anyone know if there is a drill mill that I could do the hole drilling and counter sink in one peck drilling operation?

Don’t know where to find such a mill, but they likely exist somewhere, you just need to know the angle and diameter.

I believe the countersink angle of the typical M2 is 90 degrees:

I looked on McMaster Carr as well as MSC and don’t see one that small, only M3. You might have to do two operations, drill then countersink…or search more than I did.


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Edit: somehow I missed “single op”, sorry :laughing:

I use an Amana #45612 for chamfering and spot drilling in aluminum, works nicely. Could try doing a chamfer or drill op in Fusion 360 at the right depth with it.

Looks like you would do 1.2mm depth

Maybe this will redeem my previous post?

Not much of a LOC and I wasn’t sure if you were trying to cut threads in the hole after?

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These look intriguing. I want to drill a clearance hole for an M2 screw as well as adding the chamfer/counter sink preferably in one operation. Lucky me it is in .100" plate so these should work. I need to run 160 holes/counter sinks in my first set up with the potential for more in the future. So if I can eliminate a tool change or two that would help alot.

If I’m reading the above correctly the diameter of the drill portion on these is 0.060”, which is just over 1.5mm. Don’t know that this will do it for an M2 screw.


That’s an interesting statement… One tool change will hardly affect your tooling time, and even less so with more holes. Mill the holes (drills are NOT a good idea in a router, just in case you were thinking of going down that path), which will take more time than you might think, then mill the countersinks, which could be done with a chamfer bit of the appropriate size and angle. That’s one tool change during the first setup, not 160.


That tool is not a drill/countersink, but can be used to produce the hole by drilling then a boring operation to size, then the tip can be used to form the countersink. I use them frequently for a variety of tasks, including engraving, milling countersinks for small holes, isolation milling circuit boards, and other fine work.

They are a compromise tool, but do ok if you don’t go too hard and avoid the tip for any side loading. For countersinking, I use paths that start inside and bottom depth of the sink and work out and up, keeping about 20% radial engagement. Much more radial than that requires really slowing the feed down to avoid the tip snagging and breaking the tool.

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Well there is potential to have to do 25-50 setups so tool changes are still sucky lol. I want these to more or less run while I work on other things. I have a spindle so drilling isnt out of the question.

I will probably end up boring the hole and then coming in with a chamfer mill and peck down to the proper depth for the chamfer.

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