Click on a label to read posts from that part of the world.
Life Nomadic: How Airport Metal Detectors Work

I'm a bit fanatical about shaving. Most of my possessions are pared down to the bare minimum, but my shaving stuff is the one big exception. I use a Merkur travel safety razor with Merkur platinum coated blades, a Dovo silver tip shaving brush, and Truefitt and Hill shaving cream.
Excessive, I know.
The blades that the razor uses are standard "safety razor" blades. They're thin pieces of metal with a blade on each side. That sounds like something that the TSA would possibly prohibit, but in fact they don't. They mention them specifically in their rules.

They prohibit "Razor-Type Blades - such as box cutters, utility knives, razor blades not in a cartridge, but excluding safety razors."
Clearly, safety razors are permitted. This is consistent with my experience, too. I'm almost invariably selected for further screening. TSA agents see my razor blades and move on.
And somehow I've managed to resist any temptation to hijack a plane with them so far.
In New York a few weeks ago, things were different. The TSA agent didn't like my razor blades. I insisted that the TSA rules permitted the blades. Things got escalated to the supervisor, an icy woman named Gohel.
"I specifically checked the TSA site and saw that these are allowed. Can we please look over the rules together?"
Gohel told me in clear language that the blades would not be allowed on the plane, and that, no, I could not look at the TSA rules with her. No amount of friendly yet firm pleading would change her mind.
The blades were taken.
I anticipated that this might happen, so I came up with a way to pass small metal objects through the metal detector. I doubt any serious weapon could possibly make it through, but it's great insurance for those worried that poorly trained TSA agents will confiscate items you're legally permitted to carry on.
Metal detectors work on a simple principle. One of the walls of the arch you walk through sends pulses of radio waves to the other wall which bounces them back. Their return is timed, and if they come back too soon then they've hit metal.
However, they don't pick up every bit of metal. If they did, then people with metal fillings, metal rivets on their jeans, and metal rings would be unnecessarily detained. The sensitivity is always turned down a little bit.
Because the radio pulses are coming from side to side, if a metal item is aimed so that its thinnest profile is facing the walls of the arches, it is less likely to be detected. I keep a spare blade in my wallet, and it has never set off a metal detector.
There's no way to know exactly how much metal can pass through a metal detector undetected. I'm sure that the higher ups at the TSA have metal detectors calibrated to catch anything big enough to pose a serious threat.
I have successfully passed safety razor blades as well as small pairs of scissors with no problem. The TSA rules clearly allow scissors under 4", but agents sometimes have problems with those as well.
Trying to get anything seriously dangerous past the metal detectors would be a very bad idea. I've been randomly patted down before, and I wouldn't want to be caught with something that isn't clearly allowed by the TSA.
But if you're sick of being subject to poorly trained TSA agents' whims and opinions, consider keeping your razors and scissors away from them and their metal detectors.
Filed under: Airports, Life Nomadic








Reader Comments (Page 1 of 1)
u07ch Mar 5th 2009 1:06PM
Like most frequent flyers am not used to setting the detectors of. Though In December 2001 when everyone was still super paranoid, i set of a both the arch and a hand held metal detector in Papetee French Polynesia; i had a piece of foil gum wrapper in my pocket. Never seen such a sensitive detectors before or since.
washarp Mar 5th 2009 1:39PM
First off, I don't think you really understand how a metal detector works because your explanation is flat out untrue and your passaround scheme is faulty logic. The razor blades sneak by because they're not very big, they are under the threshold of the detector, they won't make the detector go off regardless of their orientation.
Secondly, is it smart to be sneaking sharp things onto a plane? I'm gonna go with no. That's how people end up in prison, and justly so. I'm not a lawyer, but I'm pretty sure you've committed at least one felony by publishing this. Stuff like this is how the terrorists win. Do you want the terrorists to win?
Justin Glow Mar 5th 2009 2:42PM
How is explaining how to "sneak" an allowed item onto a plane "letting the terrorist win"?
nismo334 Mar 5th 2009 2:45PM
if a safety blade is permitted no a plane then there is nothing illegal about having it. If someone finds it, it's on the TSA site as an explicit exception, mening it's allowed. You can't get in huge trouble for something they allow. I think this is a good idea to get past less screeners who don't know all the rules. Another option is to keep a printout of the rules, directly from the site, in your bag and display them if you get hassled about it. This also goes for carry on or checked bags, so you don't get charged oversized or overweight fees incorectly.
Emland Mar 5th 2009 1:54PM
I was a TSA screener in 2002-2003. Permitted items were changed on a daily basis (probably not, but it seemed that way). They may not remember the "safety razor" exception - they just key in on razor = no. The Lead or Supervisor is going to back them up to save face. It isn't right, but that's how it works.
So much depends on the training at the airport and how harried the screener is. When I was with the TSA our supervisors would load themselves or another screener with various threats, i.e. razors, knives, ice picks etc to see what we could get past the WTMD. The airports I have been in recently appear so short staffed I doubt they have the time to train like that.
I don't believe you have violated any laws because you can get info on the WTMD and the other devices used by TSA by surfing the internet.
boomboxnation Mar 5th 2009 3:00PM
Lighters always make it through as well FYI.
johnmc Mar 5th 2009 6:22PM
Lighters are no longer banned from carry on.
Marvin S. Mar 5th 2009 4:51PM
I am not sure that all metal detectors are set to equivalent sensitivities which will make "ensuring" that you can pass through all them impossible. Back in the late 90s, I used to travel out of LAX frequently. One day, I took a day trip to SJC and later in the day, I had to pick someone up from a different terminal at LAX. I was wearing the same clothes/shoes and had the same pocket contents. I did not set off the detector the first two times of the day, but did the third. They claimed it was my shoes.
There are no guarantees heading through airport security.
Tynan Mar 5th 2009 4:55PM
I agree. The most sensitive one I've been through was actually a domestic flight in Panama.
Tynan
Alex Mar 6th 2009 10:58AM
On my return flight from Manchester,UK to Philly last summer, the guy at the beginning of the conveyor said the change I was holding wouldn't set off the metal detector. It did. (Maybe because it was American) The agent past the metal detector was kind and courteous and made sure my mom was standing by when he patted me down. (I'm 15.) Why can't all airport security be like him?
David Mar 6th 2009 5:52PM
Yeah, that isn't how metal detectors work at all. They use magnetic induction to gauge the presence of conductive objects. The method you propose will only work if the set sensitivity of the sensor is above the threshold that a small razor blade would trigger.
Jeff Mar 6th 2009 4:55PM
I use a very similar shaving setup at home but I have to give it up when I fly. I've had several conversations with TSA screeners and they all have agreed that their definition of "safety razor" is the disposable plastic variety, not an actual double edge razor. I've thought about trying to sneak a blade on my person, but I'm worried that an x-ray of the empty razor in my carry-on would prompt additional inspection and trying to explain a naked razor blade hidden in my belt would be kinda hard to explain.
boredwell Mar 7th 2009 2:22AM
I'm don't think an expose on how to pass metal objects through detectors is a real service to readers even those of us who are frequent travellers. Although the TSA rule book exempts safety razors, I generally would prefer my flights to be sharp-object-free (including scissors). If you don't check baggage (where you could keep your stash), you could determine where to buy them when you reach your destination.
alex Mar 9th 2009 8:29AM
while the rules you posted indicate you can have your razors, they also indicate that they should be checked. the fact that you had them at the x-ray means you were trying to bring them carry on.
JD Mar 15th 2009 8:13PM
He posted it because it shows the exception. its saying that the razors can be checked, but not brought on, the razors are the exception to what can not be brought on but checked.
shosko@gmail.com Mar 10th 2009 5:16PM
Hey Tynan, love your posts. I just have to ask though, what is your line of work? Have to ask since it permits such an excellent lifestyle of travel :) Cheers!