On
10 September 2024 at 16:24 Steve355 Said:
Now though I will need to mill a bunch of M8 holes though 25 mm of aluminium, so I’ll need an appropriate cutter for that (?) . Alternatively use the CNC to mark starter holes and do it on my pillar drill.
Drill them with the CNC…
I used M6 on a 38 x 38 matrix (as a compromise between the number of holes, something that would cover most of the available travel and avoiding various existing fasteners). I think I used 5000RPM for the drilling the 5mm holes, which is on the fast side, but it worked.
I spot-drilled first, then drilled through, then chamfered the tops of the holes. I tapped them by hand which seemed to take ages – might want to look at thread milling them on the CNC, especially if you stick with 25mm spacing.
Some rough video:
Spot drilling
Drilling
Chamfering
(I had to reduce the toolpath radius in the chamfering op as I ran out of machine travel. It looks like the tool is just plunging, but it is, in fact, circling around the top of the hole.)