Eel Vg10 Original Filipino Balisong butterfly Knife BF-40

The BF-40 Eel is a 150g VG10 balisong, brass with kamagong wood inserts, 12cm blade in a 24cm frame. It is one of the light builds in the animal series, which makes it a knife for continuous rolling rather than one for looking impressive on a shelf. And since rolling is really a question of how well two pivots turn, that is what this page is about, because it is the part of a balisong nobody photographs and everybody feels.

The pivots are the knife

A balisong is two handles hanging off a blade on two pins. Everything you enjoy or hate about flipping one comes down to how those two joints behave. The steel gets the marketing. The pivots do the work.

What you want is both sides turning with the same resistance, and turning freely without any side-to-side play. Those two goals fight each other. Tighten a pivot until the play disappears and it binds. Back it off until it spins forever and the handle starts to wobble against the blade. The setting in between is narrow, and finding it on each individual knife is a job done by hand, one knife at a time, because no two sets of parts are dimensionally identical no matter how carefully they were cut.

How to tell whether a balisong is tuned

• Drop test. Hold the closed knife by the blade, let one handle fall. It should swing open under its own weight, smoothly, and the other handle should do the same.
• Both sides the same. If one handle drops faster than the other, the knife will fight you in one direction and you will blame yourself.
• No lateral play. Squeeze the closed handles sideways. Movement here is the thing to be fussy about.
• Listen. A well set pivot is quiet. Grinding means something inside is not turning where it should.

Keeping it that way

Very little is required and most of what the internet recommends is too much. A drop of light oil at each pivot every few months, worked in by opening and closing the knife twenty times, then wipe the outside. That is the whole routine.

Do not pack the pivots with thick grease, because it collects pocket lint and turns into a paste that slows the knife down. Do not soak the knife in solvent to clean it, because that strips the pivots and leaves them dry. If the action changes suddenly, the usual culprit is a pivot screw that has crept loose from vibration rather than anything dramatic.

Specifications for this VG10 kamagong balisong

Why 150g suits continuous work

Light knives change direction without arguing. At 150g the Eel starts easily, reverses cleanly and lets you practise long enough to actually build the muscle memory, where a 180g knife would have your forearm asking questions after twenty minutes. The trade is that aerials are less forgiving, because there is less mass holding the knife on its line once it leaves your hand.

The steel, and why VG10 suits a butterfly knife

VG10 is a Japanese stainless developed for kitchen knives, roughly 15% chromium at around 60 HRC. Fine edge, good retention, and no rust from a sweaty hand. It is the cheapest steel band on this site, which reliably surprises people. The catch is that once it does go dull it takes more patience on a stone than 440C, hardness being a two-sided gift.

Trainer, sheath and shipping on this drop point balisong

The option above the Add to Cart button orders the Eel unsharpened, with the same pivots and the same tuning. A fitted leather sheath is included. Shipping is free within the US and a flat $49 worldwide.

the VG10 is taken to 58-60 HRC, the same hardness we use across the whole shelf.