I purchased this 18650 host from Lightknot, it's very well made, and designed for an 18650 cell. However, I have plenty of 6P torches, and not enough 3P torches. So off with its head! or, rather the tail 
The distance to remove turns out to be exactly the length of an CR123, 1.315"
A little lathe magic to reduce to the threading OD, and then pour on the 20tpi threads
It feels good to be able to make relatively simple operations like this. Two years ago, I was not as confident in my threading skills.
End result, with an RPM tail and stock SF head.
Also with a Conklin fountain pen from the 1950's, if you were curious.
It just feels great in the hand. I'll have to make up a dedicated engine for this host, I was using one from another of my torches for testing. I do have an amber LED, maybe I'll put together that with a simple driver.
Then I'll figure out if I want to cerakote the whole thing. If I do that, it'll be something interesting like navy blue or forest green. Something non-standard.
The distance to remove turns out to be exactly the length of an CR123, 1.315"
A little lathe magic to reduce to the threading OD, and then pour on the 20tpi threads
It feels good to be able to make relatively simple operations like this. Two years ago, I was not as confident in my threading skills.
End result, with an RPM tail and stock SF head.
Also with a Conklin fountain pen from the 1950's, if you were curious.
It just feels great in the hand. I'll have to make up a dedicated engine for this host, I was using one from another of my torches for testing. I do have an amber LED, maybe I'll put together that with a simple driver.
Then I'll figure out if I want to cerakote the whole thing. If I do that, it'll be something interesting like navy blue or forest green. Something non-standard.
