My .02 on making holes to aluminium, sheetmetal and plywood:

- Aluminium and sheetmetal:

-- Drill saws with thin sheet: jam, wobble off, break the center drill bit.

-- Bolt punch: excellent, works good up to 2,5mm (0,1 in) sheetmetal.
slightly expensive, but works good. A bit "high maintenance", bolt
threads collect debris eagerly and jam without regular cleaning.

- Plywood

-- Best way to spare eg. mahogany strip surface is to START BY ROTATING
BACKWARDS ... might sound silly, but surfacing stays intact that way.
when thru surface, redo from other side, then switch to right direction
and saw through.

Cheers,
Petri