Countersinking 4mm bolt

[2G's]

I need to countersink a 4mm bolt, if I'm reading this chart correctly the diameter at the top of the hole is 4.8mm and the depth is 4.4mm. My question is what do I need, to make this countersink? What do I use as far as countersinks are concerned? TIA

Greg

 

[Brento]

You are reading the chart wrong. The diameter of the top of the countersink is 4.7 mm the clearance for the screw going through the hole is 4.8 for a normal fit and 4.4 for a tight fit. Honestly best way to do it is take a countersink cutter and just cut at the location you want, retract the tool and put the bolt in the whole and see if it sits below the surface.

 

[kd4gij]

Here is the correct tool

https://www.amazon.com/HHIP-2007-0055-High-Speed-Straight-Counterbore/dp/B01I5PFLPU/ref=sr_1_3?gclid=CjwKCAiA6Y2QBhAtEiwAGHybPcsN3NIC8B6IuWsRmZlOD-N2ec8NBFlcj2xcjG9pi3Qn7JManWJHHRoCdTQQAvD_BwE&hvadid=580843372257&hvdev=c&hvlocphy=9012133&hvnetw=g&hvqmt=e&hvrand=4655722027728113003&hvtargid=kwd-367314782098&hydadcr=5102_13195402&keywords=m4%2Bcounterbore&qid=1644451058&sr=8-3&th=1

 

[kd4gij]

That is for a socket head bolt. witch is counterbore

 

[Brento]

That is for a socket head bolt. witch is counterbore

He was asking for a countersink though

 

[benmychree]

You are reading the chart wrong. The diameter of the top of the countersink is 4.7 mm the clearance for the screw going through the hole is 4.8 for a normal fit and 4.4 for a tight fit. Honestly best way to do it is take a countersink cutter and just cut at the location you want, retract the tool and put the bolt in the whole and see if it sits below the surface.

This is the best answer; cut and try!

 

[kd4gij]

Yes if he is asking about a flat head screw then he needs a 90 deg counter sink.

 

[2G's]

Yes I was asking about countersink not counterbore, however I am not sure as to which way I want to do this. The reason for asking this question in the first place was that I need to drill holes in a aluminum router plate that is not drilled, so that I may use my router in a table top. What would look better I believe would be to countersink the bolts, but might be easier to counterbore ! Also I am not sure as to what degree the flat head bolts are, I've heard they might be 60 degree.

 

[benmychree]

The above post is right, metric FH screws are 90 deg included angle, not 82 like USA

 

[RJSakowski]

Metric flat head screws take a 90º countersink.