Epic fail drilling into aluminum

[fastpakr]

I have a set of signal lights to add on to the hard cases that live semi permanently on the motorcycle. After gathering the lights, ordering a breakout harness for the factory wiring (to avoid cutting into anything), finding weatherproof screw down connectors to pass everything through, etc, I thought I had a solid plan.

Then came the showstopper I never expected…

The cases are just aluminum, maybe 1/16 thick. And I have failed MISERABLY at drilling into it. Every bit I’ve tried just happily spins right on the surface without biting in at all.

I’ve got a nice center punched dimple to get things started, so the bit isn’t walking at all. Brand new titanium coated bits. Oil to keep the bit from overheating. Pressure against the back of the drill. Steady low rpm. After minutes of consistent drilling, I’m lucky to have a decent mark showing where the bit was turning.

What the heck am I missing? I’ve drilled through thick steel faster than this. So far I’ve managed one hole after hours of experimenting, and that one mostly involved frustration and burning my way though. That leaves another 14 holes to drill and I’ll be lucky to finish before Medicare kicks in.

All I need is a 1/8 hole. Once I have that, a step bit rips through the aluminum to whatever size I need (the one successful hole proved that). It’s not that the aluminum is exceptionally strong or anything. It’s just protected by Elvish incantations that are beyond my skills.

 

[Curious Hound]

Try putting the drill in "forward".


Seriously, it sounds like you're drilling stainless steel.

 

[fastpakr]

Try putting the drill in "forward".


Seriously, it sounds like you're drilling stainless steel.

I have checked the drill direction so. many. times. Everything in me wants that to be it.

I guess it’s possible that they’re really stainless, but they certainly aren’t advertised as steel. Magnet test?

 

[Curious Hound]

Magnet test?

Most stainless steel alloys are non-magnetic. so, that may not tell you much.

 

[Roert42]

Could be chrome plated.

Chrome is very hard, very adverse to abrasion.

Aluminum is very soft, like copper, and drills super fast.

 

[fastpakr]

Could be chrome plated.

Chrome is very hard, very adverse to abrasion.

Aluminum is very soft, like copper, and drills super fast.

Yeah I’ve never experienced anything like this before with aluminum.

 

[alwaysFlOoReD]

Cobalt drill bits work on stainless. If that doesn't work then it's chrome plated. For that use a dremel grind stone to remove the chrome.

 

[85_Ranger4x4]

 

[alwaysFlOoReD]

I have a set of signal lights to add on to the hard cases that live semi permanently on the motorcycle. After gathering the lights, ordering a breakout harness for the factory wiring (to avoid cutting into anything), finding weatherproof screw down connectors to pass everything through, etc, I thought I had a solid plan.

Then came the showstopper I never expected…

The cases are just aluminum, maybe 1/16 thick. And I have failed MISERABLY at drilling into it. Every bit I’ve tried just happily spins right on the surface without biting in at all.

I’ve got a nice center punched dimple to get things started, so the bit isn’t walking at all. Brand new titanium coated bits. Oil to keep the bit from overheating. Pressure against the back of the drill. Steady low rpm. After minutes of consistent drilling, I’m lucky to have a decent mark showing where the bit was turning.

What the heck am I missing? I’ve drilled through thick steel faster than this. So far I’ve managed one hole after hours of experimenting, and that one mostly involved frustration and burning my way though. That leaves another 14 holes to drill and I’ll be lucky to finish before Medicare kicks in.

All I need is a 1/8 hole. Once I have that, a step bit rips through the aluminum to whatever size I need (the one successful hole proved that). It’s not that the aluminum is exceptionally strong or anything. It’s just protected by Elvish incantations that are beyond my skills.

Can you post a pic of the tip of the drill bit?. New and once drilled. I want to see where it's doing the work.

 

[85_Ranger4x4]

Can you post a pic of the tip of the drill bit?. New and once drilled. I want to see where it's doing the work.

A picture of the part in question probably wouldn't hurt either.

 

[fastpakr]

It might be tomorrow but I’ll get some pictures posted.

 

[lil_Blue_Ford]

Probably not the problem, but I’ve learned the value of quality bits. I stopped buying Harbor Freight bits after that because I realized they usually aren’t sharpened very good and aren’t typically a great quality of steel. Good bits aren’t exactly cheap though.

I had to drill out some lug studs because some lunkhead ugga-dugga’d the lug nuts down and broke them off in a friend’s aftermarket rims. I went through a couple $30 Milwaukee branded bits. Nothing else was making any progress on the hardened steel and those were the best bits I could find locally.

 

[fastpakr]

I’m 100% willing to invest in the right bits for this job once I’m sure what that would be.

 

[Ranger850]

Is it "aircraft" aluminum? like 7075-T6? Because I've used a self tapper as a drill many times on thick aluminum. It has to be the metal and NOT the bits your using.

Why 7075-T6 is Difficult:

• • Extreme Hardness: It is highly abrasive and will quickly dull standard High-Speed Steel (HSS) bits.
  • Work Hardening: The friction and heat generated during drilling can cause the metal to harden in place, binding or breaking the bit. [1, 2, 3, 4]

Tips for Drilling 1/8th Inch Aluminum:

• • Use the Right Bits: Switch to Cobalt Drill Bits or coated carbide bits, as they dissipate heat better.

 

[89longbed]

Stainless is also very susceptible the work hardening. You may need to grind away a bit of the surface to expose metal that a drill bit can bite into. You always want a bit to bite into stainless as soon as possible, and use oil to disipate heat.