limited production :: hand crafted :: high performance :: rechargeable :: premium flashlights

This is my blog about creating a startup LED flashlight business. I'm a designer, fabricator, and strategist and I'm passionate about making ideas real. I believe that products are about people, that they should be built to last, deliver real value, and that we need to do a better job than we have in the recent past.

Most of my career has been contract or freelance work and I've crafted products and strategies for both big international companies and startups. I also used to work in the "industry" fabricating special effects for film and TV, along with the occasional hot rod. Bottom line, I love making things.

I'm starting this blog so you can follow along, from day one, and see what it's like to start a business, or fail in the process. Only time will tell, but I hope you find this interesting enough to stay tuned, comment, link, like, tweet, and (most importantly) participate in turning this idea into something tangible and valuable.

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Friday, April 20, 2012

WIN: I modded the world's best flashlight switch

I should say right up front this is going to get pretty geeky. Like comparing two different types of springs geeky. Better buckle up. I was at a manufacturing trade show (better latch that tray table as well) and found a company called Smalley Steel Ring Co. They make some really interesting stuff...enter the wave spring. It's time to loose the conical battery contact spring and get with the wave spring. I'll be integrating these into my lights as soon as possible.

No flashlight should use anything else. So, when everyone starts doing this, you heard it here first :) This is henceforth known as the "Prometheus Spring!" Cue the music...or you can just check out my first prototype integration after the jump.

They even look cool right? Besides that, there are even more advantages over a standard conical spring. Here are the highlights:
  1. No sharp edges. A typical conical spring is really sharp where the last coil is cut off and that cuts into the thin metal on each end of the battery. Long term...not good. It also makes the light feel awful and "scratchy" when opening and closing. Right now I have to put a blob of solder on the PCB spring and the McClicky switch spring to prevent them from destroying the batteries.  
  2. Distributed contact area: Each wave spring will contact the battery at the crest of each wave...typically 4 different places. A conical (or coil) spring only has one point of contact. Multiple contact points distribute the load generated when the light suffers shock...for example, when dropped. Every effort should be made to protect li-ion batteries from physical damage. 
  3. Shorter current path. In a typical spring the current must pass along the entire length of the spring, as if it were a straight wire. More distance equals more resistance, and resistance is bad. As you can see in the photo above, each crest touches a trough, making the current path incredibly short.
If you made it this far you might as well read on after the jump. More photos! You like photos right?

Standard McClicky on the left...modified on the right
If you aren't familiar with the McClicky switch, it was designed by Don my mind, the foremost custom flashlight builder of all time. It's THE industry standard for tailcap switches and is considered better than any mechanical switch used by any manufacturer. Always room for improvement right? :) I told you I can't leave anything alone. 

I've spent several months corresponding with the engineers over at Smalley and they were able to find me a sample that is a direct replacement for the stock spring. My sample is heat treated stainless but I'd have springs custom manufactured from beryllium copper and then nickel or gold plated. Gold is nice but have you seen the prices lately? 

A direct replacement for the stock spring
The fit is amazingly perfect and can be installed on the McClicky without any modification whatsoever. Unfortunately removing the original spring and replacing it with a wave spring is pretty hard. It would be dead simple to replace it during manufacturing though. Anyone need like 1000 of these? Seriously though, if you are interested please comment and maybe something can be arranged if there is enough interest. 


  1. I like it. I would definitely be interested in retrofitting my Alpha with this switch and when I FINALLY get another one, I will be interested in having it there as well.

  2. Do they make bracelet sized springs cuz that's pretty

    1. YES! they do. You should call and get some samples. I tried some on at the show...uh oh. I'm having an idea.

  3. Damn that's nice.

    Can I have this spring on my Alpha please?

  4. aflashinthenightMay 8, 2012 at 12:24 PM

    what's next

    a Titanium switch, a bit like the one Steve Ku makes for the Ti V10R, to replace those ugly rubber boot.

  5. I'd take 1000 of these (just springs), please contact me at serge [AT], many thanks!