No no no no no no no 3.5mm is WAY too huge. The #6-32 machine screw is approx. 2.8mm in diameter.
You can use a 7/64" drill bit also...
I discovered it quite by accident...literally by grabbing the wrong size drill bit out of the box.
When I got my KF4, I was using the same size coil I'd always used, built on a 5/64" (2mm) drill bit. But while that worked for the
kayfun Lite series, the KF4 didn't like it so much.
The KF4 stock airflow is much more open than a KFL, and so I determined I'd need a bigger diameter coil to put up with the wider airflow. I meant to go one size up, to a 3/32" bit (2.383mm - though most call it a 2.5mm, even though a true 2.5mm bit is somewhere between a #40 and a #39 bit) however, I grabbed the 7/64" (2.8mm) bit instead. Needless to say, that was the right move, as my KF4 exploded with flavor, instead of being super muted like it had been.
One day I got curious, and kinda tired of having to build two different sized
coils, for my lonely KF4 and my many KFLs...I decided to pop a 7/64" (2.8mm) coil on my KFL, and it worked great! It actually improved on what I had thought was a perfect build!
I went from 8/9/10-ish wraps (I think) on a 5/64" (2mm), to 5-6 wraps on a 7/64"(2.8mm) and got a slightly lower resistance coil, with the larger diameter, which allowed for better wicking.
In my experience, switching from 5/64" (truly a 1.984mm aka 2mm) diameter coil to a 7/64" (truly a 2.779mm aka 2.8mm) coil has improved on wicking and flavor in all my Kayfun models.
People always think I'm crazy, but then they try it.
Getting a #6-32
machine screw was the next logical step for me. Same diameter (or close enough for government work), and it helps space the wraps perfectly. I don't like contact coils anymore, as they tend to get little hot spots of dry wick inside them. With a spaced coil, I see thorough saturation of the wick.
Have fun! Sorry for mathing and numbering at you. I have a tendency to be a little too thorough.
Edit: On quadruple thought, it might be easier for someone to grab a metric drill bit set, and avoid confusion, if they're really worried about being super accurate. Honestly, the 0.221mm lost in the mental conversion of 7/64" (2.779mm) to 2.8mm doesn't really bother me...even though I am sure there are some who would lose their marbles over it. In reality, a true 2.8mm bit is sized somewhere between a #35 and #34 bit.
P.S. Edit: On topic - I want an Onyx Black Radius, but I'm probably gonna wait for the Stealth...I really doubt I'll need two. But if I do, I'll get the Onyx Black...it's a shame there's no Satin Silver.
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