Cannot drill through bumper
Joined: Sep 2008
Posts: 19,800
Likes: 1,089
From: Ohio
Bumpers can be hard. I did the same years ago on my old 93 when I was tapping holes to mount lights, ended up getting a punch and diamond tip from local hardware store and that did it fine but my regular drill bits didn't cut it at all.
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,523
Likes: 7,633
From: MI
They're okay, a step down from a cobalt bit.
Titanium drill bits are only good for drilling metals such as brass, soft steels and aluminum. On the other hand, cobalt and carbide are designed for drilling hard and slippery metals such as stainless steel, nickel, phosphor bronze, cast iron, etc. That's why cobalt and carbide drill bits are so much more expensive than titanium and high-speed steel bits.
Titanium bits only have a thin surface coating of titanium over a carbon steel core, so when the titanium wears off, you're left with a high speed steel bit.
A cobalt bit, on the other hand, is solid all the way through, not coated, so it can be resharpened many times and still provide the same performance.
You can easily verify this via a simple web search.
Overall cobalt is the better choice for long-term usage in hard metals.
They're okay, a step down from a cobalt bit. Titanium drill bits are only good for drilling metals such as brass, soft steels and aluminum. On the other hand, cobalt and carbide are designed for drilling hard and slippery metals such as stainless steel, nickel, phosphor bronze, cast iron, etc. That's why cobalt and carbide drill bits are so much more expensive than titanium and high-speed steel bits. Titanium bits only have a thin surface coating of titanium over a carbon steel core, so when the titanium wears off, you're left with a high speed steel bit. A cobalt bit, on the other hand, is solid all the way through, not coated, so it can be resharpened many times and still provide the same performance. You can easily verify this via a simple web search. Overall cobalt is the better choice for long-term usage in hard metals.
Thread Starter
Senior Member
Joined: Oct 2013
Posts: 101
Likes: 0
I appreciate everyones help and educating me. My knowledge when it comes to metal work and drill bits is very limited, as I'm sure you all know by me hoping a masonry bit would work lol.....I'm going to try a cobalt bit in the mornin and see if it works! Now can I use a smaller cobalt bit just to get through and then use a titanium bit to make the hole the right size? Or should I buy both a smaller bit for the pilot hole and also buy the proper size bit for the final hole?
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,523
Likes: 7,633
From: MI
There's M35 and M42 grades of cobalt bits. I believe it's 5% vs 8% of cobalt alloy in the mix. The M42's will definitely last longer and are harder bit. But with that, they are more brittle than the M35's.
Always use oil , cutting oil or anything you find laying around, - regular motor oil is better than nothing. They all will last longer if you slow down and feed it some juice.
BTW- fleabag, is probably the most economical place to collect bits, taps/dies; - The quality machine shop stuff. They are still pricey, but if you collect them slowly, 3 or 4 at a time, it's easier to stomach paying that price. Yea, e-Bay, there's more than just a few that don't know what they are selling and you may get lucky.
Other than that, for a small set of M42's, expect to pay a little over a $100.
Always use oil , cutting oil or anything you find laying around, - regular motor oil is better than nothing. They all will last longer if you slow down and feed it some juice.
BTW- fleabag, is probably the most economical place to collect bits, taps/dies; - The quality machine shop stuff. They are still pricey, but if you collect them slowly, 3 or 4 at a time, it's easier to stomach paying that price. Yea, e-Bay, there's more than just a few that don't know what they are selling and you may get lucky.
Other than that, for a small set of M42's, expect to pay a little over a $100.
Last edited by Jbrew; Mar 13, 2014 at 07:39 AM.
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,523
Likes: 7,633
From: MI