Is there a limit on them?
Might be in for 20 big and 20 small.
No limit. 1000pcs is just the minimum order. The more spring we can get manufactured though, the lower the price per spring will be.
Bulk purchases really help getting the cost down by a huge factor.
Please add 30 small to my original order post #8
Thanks
List has been updated.
One other thing: would you prefer better spring mechanical properties using Beryllium Copper 38% IACS C17530, or slightly better conductivity using Beryllium Copper 45% IACS C17510?
I would like to know your choices.
20 Large
15 Small
List updated.
1011 big springs and 452 small springs.
45% is the point of the group buy 
Is it?
I though it was about providing a better spring than the existing 45% option.
Not only larger bit with better mechanical properties. (Main factor for a spring!)
So that would mean de slightly lower conducting 38%. It has still awesome current capabilities, enough for most of the builds.
When I had the djozz springs made a few years ago by the Tevema factory, the price break for bulk purchase (20 cents! instead of a dollar) was 2000 springs. At the time there was no way there would be interest enough for 2000 springs so I did not dare to go for that number. I’m glad that the interest is so high this time, that helps enormously for the price!
Please please go for the better mechanical properties, the intl-outdoor spring works fine for such a short spring with little travel but a longer spring of the same material will fail bigtime mechanically.
In for 10 big springs
As thijsco19 & djozz said…. the better spring mechanical properties using Beryllium Copper 38% IACS C17530 is surely the way to go.
I was thinking this was already decided?? But either way…. please do go for the better mechanical properties of the 38%.
Thank you for doing this Group Buy also!! :+1: .
@teacher, I was just checking with the community to see if they wanted something else.
This past, I spent a lot of time during my free time during research about which type of beryllium copper that we could use in a spring application.
There are other types of beryllium copper that would be even better suited to a spring. However, they only have 22% IACS, and therefore, not worth the money over a phosphor bronze B-2 spring at 19% IACS.
There is 60% IACS beryllium copper that can be used. However, it is too rigid and its module of elasticity in tension is lower than 38% IACS Beryllium Copper, so not as good for a spring.
TLDR: 38% IACS Beryllium Copper C17530 is best suited for this application.
Some questions:
The springs will be “gold plated” in other words gold color?
In a build what do you think its better to use big spring in driver or in tailcap?
Using the big and the small in a flashlight will be too tight?
Thanks
Use the small spring on drivers that have components on the back of them. A Simple FET+1 driver doesnt have any components on the back so you can use a big spring. A driver with a half dozen 7135 modules on both sides will require this skinny spring so it wont interfere with those components
1. Gold plated= gold color and gold plating for corrosion resistance
We will be using a zinc plating as it has a bit lower cost, and still good corrosion characteristics and a nice silver look, which I prefer over a gold plating.
2. Big springs almost always used in the tailcap, and small springs are used on the driver, as the contact pad of the drivers are usually way too small for such a large spring at the base(9mm), and not interference with small components.
3. No it will not be too tight. This is why dual beryllium copper springs are the grail of flashlights. It allows for universal cell compatibility, and shock absorption, compared to a single spring and a brass button, which upon a large enough shock, it will transfer the kinetic energy to the cell, and may collapse the terminal. This is no problem for a dual spring light. Most springs can’t provide low enough resistance for high power lights, but using beryllium copper 38% IACS mitigates this.
Good info BlueSwordM. … Thanks again for doing this!!! 
Thank you again teacher.
I would like to add that I also searched for brass springs, but they would probably collapse instantly if a tube were over tightened.
Zinc plating? Really? How much will that change the overall electrical resistance of the spring?
:+1: …
Nothing that is even measurable at all. It’s just a coating, between 0,75um and 1,25um, or 0,00075mm-00125mm.
The coating is so thin it does not affect electrical characteristics at all.
Nickel could be used, but zinc does actually protect the metal more from corrosion more than nickel, is less expensive, and actually has 5% more conductivity than nickel(27% vs 22%).
TLDR: For springs, zinc and gold are probably the best bet, but zinc spring is cheaper and still great, so we are going with this,