Instructables

A lapel knife is a small, easily concealed blade often used by spies in WWII. It can be hidden in a lapel, as its name suggests, or it can be dropped into a boot, slid into a sock, or even hidden in a tie. 

My lapel knife is made from a high carbon steel circular saw blade. I cut it out with an angle grinder and shaped/sharpened it with a bench grinder. The blade is chisel ground, meaning it is sharpened on one side of the blade only, like a chisel. LOA is ~ 6.5cm, with 5 cm for the blade.

I'm not sure how the knife was originally intended to be held, but I hold it between my thumb, middle and index fingers, almost like it's a key. I DO NOT recommend holding it between thumb and the middle of the index finger. I tried it this way and got a nasty cut almost immediately.

Now, this is not a knife one would use to stab through a door. It's for quick, jabbing strikes to the face, eyes, and throat. Maybe some thug's trying to pull you from your car, and you give him one heck of a poke on the back of the hand. He's going to want to let go pretty darn quick. Also, as I mentioned in my Kakute ring 'ible, head wounds bleed profusely. If this knife opens a 6" gash in an attacker's forehead, the blood streaming into his eyes prevents him from seeing clearly, giving you time to kick is legs out from under him and get away.

DISCLAIMER: I AM NOT RESPONSIBLE FOR ANY DAMAGES INCURRED, INTENTIONAL OR OTHERWISE. MAKE AND CARRY AT YOUR OWN RISK.

rickharris2 years ago
As a rider carrying this in most parts of the world would constitute a concealed weapon and lead to arrest of found.

In the UK they lock you up and throw the key away as knife crime is seen as very serious.
black hole (author)  rickharris2 years ago
Yeah, well, I think knife laws are stupid. The UK's laws in particular. Since the weapon ban started, violent crime rates have gone up, not down. What they need are stricter regulations, not a blanket ban on everything from toothpicks to AKs.
Exactly!
Exactly!
Yes...
Well said and a nice instructable.

I have a number of old saw blades and this is a good use for some of them.

The UK has outlawed guns so the thung use knives. There is talk of outlawing knives. What next, make illegal to own a baseball or cricket bat?

I live in the South. Everyone is armed and everyone is polite.
black hole (author)  Tupulov2 years ago
Thanks. Last I heard, though, it was a good long stay in jail for carrying a knife without a valid reason. (valid reason being for national dress or a job that might require a blade) Here's a very good article on the subject.
In Spain our knife law is very restrictive, and it is being doing even more restrictive.

The thug use whatever they want. If a policeman fine them (Euro 300 for a big or automatic or two sided knife) the simply say that "I'm bankrupt, I have no work, I have no house..." There is no jail or other consecuences. OK. Great.

Mommys offender. They live better.
i have a 7 inch blade belt knife i carry every day. forged it myself. i also live in the southern US....polite, yet well defended. its a good way to live
black hole (author)  The Metal One2 years ago
I guess this sums it up?
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Locomiguel2 years ago
I don't Know if you are interested but here is some information on the British SOE Lapel Knife from World War II
Lapel knife.jpg
glorybe2 years ago
If both the bottom edge and the upper edge are sharpened it is called a dagger and it is a felony to possess a dagger in Florida and probably many other states as well. It is sort of a foolish law as the bad guys usually use guns these days.
black hole (author)  glorybe2 years ago
And how much more damage will a blade with 2 edges do than a blade with 1? Either way, you've still got a few inches of steel in your chest.
carlsands2 years ago
how big is it in inches (I know its big enough that you could lay it on 4 fingers completely hidden)
black hole (author)  carlsands2 years ago
Approx. 6.5cm/2.5 inches and change.
rickharris2 years ago
Circular saw blades apart from the teeth are generally soft material (mild steel) to prevent them flying apart - this also reduces cost considerably.

The tooth tip is a carbide material brazed or welded onto the mild steel.

IF the saw has integral teeth then generally these are locally hardened rather than create a totally hard saw.
its all high carbon steel. the teeth are just locally hardened, like you said. the rest is simply left un-hardened, to prevent it from flying apart...again, just as you said. but it is all high carbon, which is the only part you got wrong