I was drilling into a thin (1/16") metal for a rear bumper and I noticed it was hardened at it wore out 2 bits pretty quick. I need to drill a couple of 3/8" holes, what type of bit do y'all recommend? Carbide? cobalt? HSS does not work.

7/12/2009 11:03:22 PM

Carbide tipped and lots of oil.

7/12/2009 11:07:01 PM

yeah, some of that cutting tool oil stuff in the aerosol can works well in my experience

7/12/2009 11:10:36 PM

does lowes carry carbide bits?

7/12/2009 11:12:02 PM

Yes. is this an aftermarket bumper? I have never come across one that was hardened

This also work well


[Edited on July 12, 2009 at 11:18 PM. Reason : ...]

7/12/2009 11:14:03 PM

its a stock mustang rear bumper. It has a layer of sheet metal added to it from the factory and that drills fine but when you hit the main bumper it good bye drill bit.

7/12/2009 11:16:31 PM

also, step up the bits.
So, start small, and then bore them out as opposed to starting at 3/8.

7/12/2009 11:17:17 PM

PM sent!

7/12/2009 11:21:44 PM

Bit - Go to Home Depot and see what the most expensive one is. That's the one you want.
AND USE SOME CUTTING OIL.
and drill slowly.
Slowly = Not smoking and fucking up your expensive bit speed.

I learned this after having to drill out a bunch of Grade 8 bolts one time. Expensive bit + cutting oil + slow drill = hole.

7/12/2009 11:24:54 PM

i've had good luck with hitachi bits from lowes on thicker/hardened stuff.

7/12/2009 11:32:35 PM

I believe you are trying to drill the impact beam, not the bumper then.

7/12/2009 11:36:43 PM

impact beam = bumper ... to most anyone

7/12/2009 11:40:41 PM

bumper means plastic on the outside
impact beam means metal support underneath

This is the garage section, where being accurate in what you are trying to do increases the number of useful responses.

[Edited on July 13, 2009 at 12:03 AM. Reason : .]

7/13/2009 12:02:20 AM

take that usless 20 lb shit off.

7/13/2009 12:05:03 AM

try drilling a smaller pilot hole first, then step up to a larger bit

repeat until you have reached the desired hole size

7/13/2009 12:14:29 AM

Quote :

"plastic on the outside"

a lot of folks would call that the "bumper cover"

[Edited on July 13, 2009 at 7:05 AM. Reason : impact beam sounds like a fancy name for bumper to me]

7/13/2009 7:04:30 AM

a good cobalt bit + plenty of tap magic will take care of anything you need

7/13/2009 7:53:30 AM