Pin System

Pin Systems are used to keep the blade from hitting the inside of the the handles and to keep the handles from hitting each other. The latter is called slap.

Material Hardness

To understand the pros and cons of every pin system, it's important to first learn about material hardness.

There are many different scales on which hardness can be measured, but the most widely-used for steel is the Rockwell Hardness scale C. It is often abbreviated to HRC.

Properly heat-treated steel typically falls in the 58-60HRC range, depending on the steel.
Non-heat-treated steel is generally around 35-41HRC.
Titanium usually has a hardness of about 36-38HRC.

The higher the HRC number, the harder the material. Harder materials are more brittle, which means they are more prone to snapping, cracking or shattering. Softer materials (lower HRC) are more malleable and deform under stress rather than breaking. For example: The handles of the Canyon are very thin and are made out of heat-treated stainless steel. Some users have reported that their handles have snapped after drops. Meanwhile, the Slift V2 also has very thin handles, but they are made of titanium. Rather than snapping, titanium will generally just deform because of its lower hardness.

If two materials that both have a high HRC hit against each other, one, if not both of those materials will be at risk of snapping, cracking or shattering.
If two materials with different hardness ratings make contact, the softer one will always yield to the harder one, meaning that the softer material will get squised and deformed. If two materials that both have a low HRC hit against each other, both of those materials with squish and deform each other, but the ammount is very small.

Different Pin Systems

There are currently three types of pin systems used in balisongs.

Zen Pins

If the stopping mechanism is a stainless steel pin housed inside the handle, it is called a "zen pin" system. There are multiple implementations of zen pin systems, but they all have in common that a pin is inside the handle.

Press-fit

Press-fit Zen pins are typically only used in Channel balisongs, as this system depends on the structural rigidity that channel construction provides. A stainless steel pin is pressed into a hole which is slightly smaller than the pin itself, creating a tight interference fit. The pin is held in place by friction generated from the pin being slightly larger than the hole, ensuring it stays securely in place during use. An example of a balisong which uses this type of Pin system is the Krake Raken.