Design of a 510 Connector

In the last few days, we’ve received quite a lot of questions, along with some really valuable feedback related to the design of the 510 connector on Roller & Dingo.

So, it’s now time to put things into perspective!

The 510 connector on both Roller & Dingo has been designed to be exchangeable / customizable, just like every other component.

*** For those of you that are new to our modware series, Dingo is the non-retractable version of Roller. It is built from the exact same parts, except for the tubing, which is interchangeable between the two. ***

Let’s see why we decided to extend this modular approach to the 510 connector design:

1) Functional Considerations

Ever thought about the role of a 510 connector?

1. It provides a universal attachment point for different atomizers.
2. It provides a path for current to flow in and out of the atomizer.

Obvious, isn’t it? Let’s get down to the dirty details!

Without doubt, material selection is one of the most critical and interesting aspects of a design. The interesting bit comes from two simple facts:

1. In most cases, there will be more than one material suitable for the occasion.
2. Some of the design requirements might point to one material choice, and some to another.

The material selection problem alone confirms one of the most well-known aphorisms in design and engineering:

Design depends largely on constraints.

In simple words, this means that there is no perfect solution to a design problem. Rather, the best possible solution is the one that yields the best combination of tradeoffs.

Most 510 connectors found on repairable mods and atomizers are built with either stainless steel or brass alloys. Aluminum, which is mostly used on mass-produced e-cigs, can be dented and cracked really easily, which makes it unsuitable for building a reliable 510 connector.

Brass is a softer material, easier to machine compared to stainless steel. On the other hand, it can get scratched more easily, too. Its main advantage, though, is its electrical conductivity, which is around 20 times better than the conductivity of stainless steel, depending on the exact alloys used. In an ideal world, this would translate into fewer losses and a higher voltage on your atomizer resistor = a better hit.

The main issue with brass is that it gets oxidized – rather fast. Additional so-called “film resistance” is inevitably created by thin layers of oxides and dirt that form on the surface of a brass contact. A clean brass contact will conduct about 20 times better than a steel one, but a heavily oxidized one will perform much, much worse.

The quality of the electrical contact between two surfaces is not only dependent on the material and the amount of oxides deposited on them, but also on their geometry:

A closer look at a contact interface reveals that all surfaces have some amount of roughness. A surface that appears smooth to the naked eye will appear to be covered with peaks and valleys when viewed under a microscope. Two mating surfaces will make contact with each other only where the surface peaks meet. These contact points are called asperities, or A-spots. The sum total of these contact areas is typically much smaller than the apparent surface area of the contact interface. Constriction resistance occurs as the electrical current must squeeze through the asperities to cross the interface. (In the same way, Santa Claus is slowed by a chimney that suddenly narrows.)

With contact force, the stress experienced by the areas in contact will increase. This means that the highest peaks in contact will yield, expanding the contact area in an effort to counter the additional force. The mating surfaces will then move closer together which allows contact to be made at shorter, wider peaks on both surfaces. This decreases the constriction resistance since there are now more and larger paths for the signal to travel through. Since the contacting surfaces are wider, the signal can more easily pass through any film that might exist. Therefore, the film resistance decreases as well.

You might have noticed this effect when measuring the voltage drop on your mods – if you press the button harder, the voltage drop will decrease a bit. This also means that the softness of brass can be beneficial compared to the hardness of a stainless steel contact. So, a brass 510 connector will serve you well – if you remember to clean it once in a while.

Even if your atomizer’s connector is made of stainless steel for extra durability, a brass female 510 connector will take most of the stress due to its softness, providing an optimal electrical interface to the mod.

Which brings us to another fact:

Every time you attach or remove an atomizer, there is friction between:

• the female 510 connector threads on the mod and
• the male 510 connector threads on the atomizer.

With every turn, tiny particles of material are slowly but steadily removed from the surface of both threads. If both are built with the same material, their decay will be slow and equally shared, which is ideal.

However, if one of the 2 connectors is built with a softer material, it will not only deform faster, but take almost all of the damage. This can be a bad or a desirable thing, depending on your perspective.

If you have an atomizer with a brass male 510 connector and use a stainless steel female as the attachment point to your mod, you’ll be slowly but steadily destroying the threads of your atomizer. Here’s an obvious question: Which of the two components would you prefer to eventually replace due to thread damage – the atomizer, or the 510 connector? Considering that:

• the 510 connector on Roller/Dingo costs as much as a beer and that
• atomizers cost at least 10 times more and usually have their threads built-in,

the answer is rather obvious.

But still, if your atomizer has a stainless steel threading and you absolutely hate cleaning, it’s okay to attach it on a stainless steel female. This may be a bit worse for your atomizer threads, but it’s nothing to worry about.

In any case, you should have the option to choose what you like, even if it’s totally wrong. Which is exactly why the 510 connector was made to be replaceable: The matter of aesthetics is subjective and can be more important to someone than function alone.

2) Aesthetic Considerations

Some people just can’t live with anything else than stainless steel and couldn’t care less about voltage drops or damaged threads. Others like their atomizers flush with their mods, and some see the gap between the atomizer & mod as a welcome aesthetic detail. Touting a particular design as the “better” one is simply not our style.

The brass connector released with Roller & Dingo is the simplest possible option in terms of form and function. In time, the options will be progressively increased, by adding different materials and styles into the mix.

Next on our list is a version designed to close the gap between the mod and genesis-style atomizers, bringing the atomizer flush with the mod. Just like everything else, it will be exchangeable / repairable. The connector, which has been designed to protect the mod surface from the wear of frequent atomizer changes, brings form and function even closer – so prepare for yet another mini-surprise!

The new component will be available as an option with Roller Custom, or as a standalone part. All Roller owners that didn’t have the chance to get the flush connector at the time they got their mods will be able to grab it for free, excl. shipping, as a small Thank You for all the valuable feedback!

Cheers,
Atmizone