Feeler thread for Beryllium Springs

Hey everybody, Merry Christmas! :slight_smile:

Trying to get an idea how a group buy would fly for Beryllium Springs. We need to standardize on a size, then see how it flies, to get an idea if they sing. Ok, nuff o that! Mattaus has checked into pricing and found that in large numbers the price goes waaaay down! Something like this…

100 - 199: $1.58ea
200 - 299: $1.338ea
300 - 399: $1.107ea
400 - 499: $0.945ea
500 - 599: $0.828ea
600 - 699: $0.739ea
700 - 799: $0.668ea
800 - 899: $0.612ea
900 - 999: $0.565ea
1000+: $0525ea

This company charges $20 flate rate per order to ship, so it would actually need to be a single purchase then distribution to make it worthwhile. Seems I have more time than most, so looks like I’ve saddled up that pony. :stuck_out_tongue:

What is the most likely size, something like 5mm x 8mm x10mm tall? I find that works well for me on drivers, upside down. Should I do a poll? First let’s get some basic ideas, I’ll try to narrow that to 3 choices, then do a poll for a final choice. Sound about right?

Have I missed anything? Y’all are gonna have to help me out here, this is all new to me…

Oh yeah, count rate. I’ll also need an idea for some standard counts, like 5, 10, 20, 50, 100. Something like that. Looks like I’ll be divvying up 1000 springs into little bags, oh boy! :slight_smile:

There will be a minimum shipping charge to cover materials and shipping, shouldn’t be much but I’ll have to find out the best way to do that. Probably small bubble mailers for the most part and a couple 2 or 3 dollars. I’ll find out and get it posted here when I do.

Ok, let’s get this party started……Cowboy Up!

Dang! Already off to a bad start! The pricing above is for this size and strength spring…

Outside Diameter 0.216 in
Hole Diameter
Wire Diameter 0.028 in
Load At Solid Length 2.135 lb
Free Length 0.355 in
Rate 9.37 lb/in
Solid Length
Rod Diameter
Number of Coils
Total Coils 4.7
Material BECU

Looks like a fairly standard size and good strength. So this will be our starting point, now’s your chance to weigh in. Yihaaaa!


Thanks for even considering this massive undertaking!

I’d be in for 10 (at least :laughing: 10mm tall is good.

Just noticed that they are silver coated as well…yum!


Good for me. It’s what I use most. What is the current capacity?

DBCstm, thanks for doing this!

Still have to look up what behrilium does to springs, but I guess it springs nice and is highly conductive, right? If the price is going down to 60 cents, plus 3 dollars for shipping, I'm in for 15

I am checking on current capacity, waiting for a return call.

Looks like it’s 22ga wire in a copper/beryllium alloy with silver plating, so the current capacity should be quite high. Again though, I’m waiting for confirmation and will post that when I find out.

Definitely need the details from Lee Spring Co, however given the material and the coating, the current carrying capacity of these springs will be high and the resistance low.

Silver is second only to carbon in terms of electrical conductivity, and one above copper. Beryllium is an allow of copper that makes it more suitable for various applications than plain old copper because it has higher strength and better workability. The best part is that unlike gold plated contacts, silver can be directly applied to copper without any intermediate coating, which means the silver can conduct the current and actually use the cross sectional area of the copper spring to carry current as well. With gold plated contacts the actual contact does sweet F.A as the nickle coating required for the gold to stick is non-conductive. So you lose the cross sectional area of the contact and only get what the gold can handle.

Or something like that.

The point is, other than a solid copper contact or braided spring (both of which would be improved with silver coating) these springs are hands down the best battery contacts we could use.

I'll be in for as many as we need to bump this up to 1000. Give it a few weeks to let people express interest, and I'll cover the remainder. I want a few hundred at least. Hopefully I wont end up with 950 lol.

- Matt

Sounds like I'll be in for 15 to 50,early days.


did someone say Beryllium Sphe-oh wait, that’s Spring, not sphere. 0:)

Interesting, does someone have some data on the resistance on these springs compared to regular ones with copper braids?

If it could eliminate copper braiding, I'd buy a bunch (10-40), depending on prices. Would be interesting to look at bigger ones (long) to replace tailcap springs too.


These springs will have a lower resistance in comparison to copper braided springs due to the materials in use and the fact it's a solid chunk of wire rather than thousands of thin strands (relatively) loosely packed together. However the overall cross-sectional area of the spring is probably lower than the copper braiding, so while these springs will introduce less resistance into the system (lower voltage drop) their maximum current carrying ability may be slightly lower. I'm going to say it will not be noticeable but I am guesstimating here.

It's all conjecture until Lee Springs gets back to us or someone gets their hands on one. I know OMGLumens use these springs in their DEFT lights.The original FETtie switch also used copper Beryllium springs and that switch demonstrated excellent efficiency gains. Mostly down to the FET of course but the spring certainly did not hinder the system.

For my use these springs will be perfect :)

I would be in for about 30 but not until after the first of the year. I would also get more if we can get longer ones for switches.

Sweet, thanks for the info.

I’m in for $15 worth of springs excluding shipping if we get over 600 units price cut.

I could use 10. Any chance they could be made thicker?

20-30 for me :slight_smile:


The only problem with longer/thicker springs for tailcaps is that it’s in addition to the driver springs. So, with these being special order due to their material it would be another starting place. 100-200 on the initial step at more than $1.50 ea. That’s another $150-300.

If we can get enough people wanting that larger tail spring I reckon we can do it both ways, but they’re going to be quite expensive as there’s not much chance we’ll get 1000 together in a group buy. Remember, longer and thicker will be exponentially more expensive than these. And at some point if the spring rate doesn’t match top and bottom then the stronger spring is not going to be compressed much if any while the weaker spring will take all the slack.

Recently, I’ve been making 5/16” diameter brass rod connections on the driver and allowing the tail spring to take up all the slack itself. This is because I’ve been stacking chips on the outside of the driver, so I used the solid rod to avoid a compressed spring shorting out the whole thing.