cut holes for ventilation pipes smoothly?

[trojlee]

I'm using a "hole-finder-kit" when making holes for electrical boxes, but what's a smooth way to get the hole for ventilation pipes in the right place? Sure, you can measure and draw and measure and draw...but is there a professional trick that makes it quicker?
best regards
M

 

[Climber77]

I am facing the same thought right now.

 

[Climber77]

It struck me that if I drill with a long twist drill through both the inner and outer wall, I have a good center hole for the hole saw.
There may be both simpler and better ways, but it works for me.

 

[Matti_75]

You can rent a hålsökare