Earwig Vg10 Original Filipino Balisong butterfly Knife BF-39

The BF-39 Earwig is a 24cm VG10 balisong at 150g in brass and kamagong. The earwig folds its pincers flat along its body when it is done with them, which is a better description of what a balisong does than most of what gets written about balisongs.

How the thing actually works

A balisong is four parts and two pins. There is a blade with a tang, two handles, a latch, and two pivot pins that the handles rotate on. The blade sits in the channel between the handles when closed and swings out of it when open. That is the whole mechanism, and it has not needed improving since Batangas settled on it.

The part nobody explains is the tang pin. It is the small pin through the tang of the blade that stops the blade rotating past the point where it should stop. When you flip a balisong open and it arrives with a solid click rather than a mushy stop, that is the tang pin doing its job against the inside of the handle. When a cheap balisong feels vague, the tang pin is usually why.

Pivot tension, and how we set it

Too tight and the knife will not fall through a rollover under its own weight. Too loose and the handles wobble side to side and the blade never lands in the same place twice.

We set ours so a handle drops freely from horizontal but does not swing past its own arc. That is on the loose side of the middle, and it is a deliberate choice, because a new owner can always tighten a pivot and it is much harder to explain to somebody that their knife is too stiff to learn on.

• If it feels tight out of the box: it has not been broken in. A hundred rollovers will free it up more than a spanner will.
• If you do adjust it: an eighth of a turn at a time, then flip it, then decide. People overshoot this constantly.
• Side to side play: a very small amount is normal on a handmade knife. Enough to see across the room is not, and we will fix it.

The latch, and the two schools

The latch holds the knife shut. Some flippers remove it, some file it down, and a large number of people find it gets in the way of chained sequences by catching on the other handle mid-rotation.

We fit it because a balisong that will not stay closed in a bag is a different kind of problem. If you decide it is not for you, taking it off is straightforward and does not damage anything. We would just rather you made that decision than have it made for you.

VG10 steel and hardness on a butterfly knife

VG10 out of Takefu in Japan: about one percent carbon, fifteen percent chromium, plus cobalt, vanadium and molybdenum in small amounts keeping the grain fine. Very keen, long edge life, and it does not mind damp.

We run it at 58-60 HRC. That is a shade under kitchen-knife hardness on purpose. A balisong meets a hard floor sooner or later, and at this hardness the edge rolls when it lands rather than chipping. Rolled edges come back on a stone. Chips do not.

150 grams, brass and a kamagong balisong handle

Light and quick, which is the right character for a knife whose page is mostly about mechanism. Chained work rewards a knife that changes direction without arguing, and 150g does that better than 180g does.

Kamagong is Philippine ebony. Dense, close-grained, near black, and stable enough to ignore a dry winter without cracking. The brass darkens over a couple of years into a brown that most owners end up preferring to the shine it arrived with.

Trainer, sheath and shipping on this VG10 balisong

The unsharpened trainer is the same knife, chosen above Add to Cart. Same steel, same 150g, same pivots, no edge. Identical price, because grinding an edge is one operation among many and knocking money off for skipping it would be a gesture rather than an economy.

Leather sheath, cut for this frame, included. Nothing to pay on US delivery. Everywhere else is a single $49 charge for the order however many knives are in it. What is legal where you live is a question only your own statute answers, and it is worth five minutes.