What to use to make a 3" hole thru battery tray

[gogeeta13]

Another user posted this a while back and I saved it, cant find the thread of origonal poster.(attached picture)

I want to know what is the best/easiest way to get a 3 inch hole thru the battery tray and body of the car right below it?

I have a huge ass air compressor, so any air tools are an option.

I was thinking just using a die grinder, but I dont know where to get any heavy duty metal bits.

[black s13]

get a 3" hole saw. thatll do it very easily.

[Rennen]

3" hole saw, or if you cant find that:

http://www.dremel.com/html/images/home/main.jpg

-Matt

[Replicant_S14]

I used on of these, but a hole saw or torch would work fine.

http://www.clssupplyinc.com/toolauthority/image/7806.jpg

[Muzzy]

a drill and a chisle....and a little dremel work

[gogeeta13]

I used on of these, but a hole saw or torch would work fine.

http://www.clssupplyinc.com/toolauthority/image/7806.jpg

what is that?

[Ghettokracker71]

what is that?
Funny....that looks like a tap-and-die set to me??? Anyway when I driled my firewall ....I killed 2 black and decker drills...then got a milwaukee close quarter drill....and titanium tipped bits...

But I would say your best bet is the hole saw

[the head]

nope that is a greenfield hydraulic sheet metal punch kit those things own for perfect holes on sheetmetal
i used a rotozip and a cutoff tool to make my holes

[Muzzy]

damn!! hydralic sheet metal punch kit!!! that must be some wicked tool

[Ghettokracker71]

nope that is a greenfield hydraulic sheet metal punch kit those things own for perfect holes on sheetmetal
i used a rotozip and a cutoff tool to make my holes
WOW!....impressive OoOooOoH!!!! Rotozip kicks ass:):)...never used it on a car,but definitely done some damage to ceilings with it !!

[meme]

i used a 3" hole saw but couldn't get it all the way through. i then used a long saw. not sure what it is called. used at some muffler shops.