I will be tapping a port on my Greddy elbow this weekend for a Aquamist nozzle. Looking at some Aquamist documentation it appears that the outer rim should be bevelled (with a ~45 degree angle) so that the o-ring seats properly.

Any tips on the particular bevel/chamfer bit size that will accomplish this?

 

The minimum bevel size is 8.8mm. Over bevelling is fine, if the manifold wall is thicker than 4.5mm. Threaded hole should be M8 x 0.75mm. Drill size is 7.2mm or 9/32".

 

Great. Thanks. Off to Home Depot to find a chamfer bit.