Diablo is the best brand drill bit in my opinion. I have only used it on wood. Which is very good. You could used it for aluminum drill slow and back out every few seconds depending on how far in you are drilling. Since aluminum is not that hard of a metal you should be fine. Remember the aluminum will get warm/.hot
Hello Leon, thanks for your message and interest in Diablo power tool accessories. We do have Forstner Bits up to a 2" size that can be found on Homedepot.com. Hope this helps. Thanks.
No. To long.
The shank is only about 2.5" long after you get it in the chuck.