Epic fail drilling into aluminum

[fastpakr]

try double cut carbide burrs instead of single cut. Clogs less in soft metal.

I didn't know they made a solid carbide bit. Pretty pricey! So yes, try them and report back.

One double cut carbide burr and two solid carbide bits on the way for delivery tomorrow, along with two tension rods so I can support the surface as I’m drilling it.

At this point we’re past just checking the box - I’m willing to spend a bit just to know what works.

 

[pjtoledo]

many choices, I've had good luck with these.

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[cbxer55]

I work on aircraft, military US Navy E-6. Drill aluminum, steel and titanium. It's been my experience, doing this since 1979 on multiple different aircraft, including the B-2 Stealth bomber, which is mostly graphite on the outside and titanium on the interior, when a drill won't bite, IT'S DULL! Period. May be a new drill, it's dull. See that frequently still to this day. Go to the tool crib, get new drills, they won't bite. Go through multiple drills until I find one that finally does.

And yeah, 7075-T6 is a very hard aluminum. On most aircraft, the exterior is 2024-T3. Very soft and allows wings to flex. That is attached to interior 7075-T6. Very hard, sometimes difficult to drill, especially with a dull drill. A sharp drill will cut it like a hot knife through butter.

 

[fastpakr]

And yet we know that’s totally wrong.

It’s possible that it’s an angle problem with bit design.

Or that it’s the material flexing because it wasn’t adequately supported.

But no, a dull bit has been thoroughly eliminated.

 

[cbxer55]

What is so funny? Very recently, was making a part for a friend's Lightning. Aluminum. Threw away a bunch of drill bits because they would not even drill 2024-T3. Just trying to drill a hole for the airbox lid on a Johnny Lightning Performance custom airbox, and the damn drills wouldn't cut. Was getting pissed, because I had used them a few minutes ago on steel. Guess the steel dulled them to the point they wouldn't cut soft aluminum.

Guess I need to take my drill bit kit to the nearby ACE Hardware and replace all the smaller bits. They're all bad.

I started working in aircraft at 18 years old, a month after I graduated H.S. in 1979. What used to be Lockheed California Company, laid off in 81. Then went to Rockwell International and helped build the B-1bs. Lockheed recalled me in 86, and worked on TR-1 Spy planes, laid off in 88. Went to what was then Northrup Corporation, B-2 Division. Worked there 11 years, laid off in 99. Went to BAE Systems in 2000, laid off after 09/11. Now work at Tinker AFB in Midwest City OK. been there since 2009. Work on US Navy Boeing E-6 Mercury's. Yes, there is a Navy base on Tinker AFB. Two Squadrons, VQ-3 and 4.

Turned 65 last week, have two pensions, one from Lockheed Martin and one from Northrup Grumman, rolling in starting August 1st. Even though I am still working.

 

[fastpakr]

Congratulations.

 

[cbxer55]

And yet we know that’s totally wrong.

It’s possible that it’s an angle problem with bit design.

Or that it’s the material flexing because it wasn’t adequately supported.

But no, a dull bit has been thoroughly eliminated.

Yeah, I know about backing up soft metal. I keep a small 4 X 4 in my toolbox at work for drilling, when needed. It's so full of holes, I need to get a new piece.

Yes, some drill bits, the tip is too flat. But I don't see that being a problem on store bought bits. In aircraft, there are a YUGE variety of different bits.

btw, drilling titanium is not as bad as most people think. Very slow drill speed, and push like you're trying to drill to China. Done properly, you get very nice swirly pigtails. Used to take them, sometimes two feet long, bend the large end slightly, and hang them off the belt loop on some dudes pants. He'd be walking around with that thing until someone told him about it. LOL!!

There is harder metal than titanium. Inconel and Monel. I dread working on those. They are work hardening metal. The hotter they get, the harder they get. Mainly used in the hot section of turbines. But once in a while, I have had to cut and drill parts for the aircraft itself. Not fun at all. If it turns red while you are working on it, it just gets harder.