Very nice springs. I am sure this has been answered but is there a reason you stuck with 1mm thick?
I would be in for 100 of them myself. Possibly more if I have the funds at that time and depending on what the final test works out to.
Two reasons actually:
1. I could go with 1.1mm or 1.2mm wire. However, the 1.1mm wire is a non standard option, so it will cost more to manufacture. But the 1.2mm wire has the same cost, so no problem there.
2. 1mm wire is already very thick for a battery spring, compared to most springs on the market already. Going with a 1.2mm wire, while better on the current handling side, will make the spring mechanically weaker.
There is a reason: free length between coils. This is for non-plastic deformation to occur at a certain compression force.
If the wire is too thick, what will happen is that under a deformation is that thereās a possibility of coils touching each other. This can end in two things: either the spring collapses at that point, or worse, the spring is stressed in a horizontal way, which will permanently deform the spring.
Either way, a thicker spring at a small size will be mechanically weaker, and since 1mm thick springs are already thicker than most springs on the market and at 38% IACS, its ability to handle current will be very high, probably 14-15A+
Makes sense, 1mm should work for most small lights that donāt see more then 15A
Yeah. Iāll probably do a comparison of all the springs I currently own, which is the Fasttech Carobronze spring, the Kaidomain Phosphor Bronze Spring, and soon enough, the BLF BSM U-Spring.
From my calculations, it should handle 14-15A before it has a voltage drop of 0,100V occurs, but I will have to confirm that once I receive them.
They are looking to be quite promising.
Wikipedia says you shouldnāt grind CuBe without respirator.
I found also regulations for beryllium powder:
http://gestis-en.itrust.de/nxt/gateway.dll/gestis_en/008020.xml?f=templates\$fn=default.htm\$3.0
Capter regulation seems worth a read. The rest I mostly donāt understand.
So do we need a saftey note for the springs, if somebody cut them with a Dremel?
Use wire snips to cut them, why on earth would anyone try to grind a springy spring? 
I donāt have immediate funds for this but in the next couple of weeks I shouldā¦ if that is ok Iād like to speak up forā¦
100 large and 50 small please.
If we have leftoverās Iād probably help you (and me) out there and buy more as well, all dependent of course on the testing of the samples.
The CaroBronze springs aggravate me as they donāt take solder well and are so stiff. The heavier Intl-Outdoor spring collapses under heavy loads (high current) and is difficult to bypass because of the thick wire and short height. So yes, I would like to stock my parts box with these more ideal BSL LS springs. 
Thanks JoeChina for making me think about this moreā¦ 
Maybe we can get up an accompanying Group Buy for those that have real concerns about the safety of these springs or might want to cut them in a manner that would create & cause dust.
I presentā¦ā¦ā¦ āThe BLF Respiratorā.
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:+1: ā¦ ā¦ ā¦
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Optional Full Facemask modelā¦ā¦
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Orā¦. be the first on your block to be completely protected from BLF BSM U-Spring dust!
ā¦ā¦
ā¦ā¦.
ā¦ā¦
Huh? The Carobronze springs are stiff? It has been the opposite experience for me.
And why would you cut springs with a dremel?
And the Intl Outdoor spring will almost always end up in a plastic deformation after being deformed, as the Beryllium Copper used in this spring has the weakest yield strength of all BeCus, no matter the current you pass through them. It is a great spring for IntlOutdoor lights, but not most other lights.
And you have been added to the interest list DB Custom.
Oh, I didnāt realize there were 2 sizes, yeah I will take 40 small springs as well.
Teacher, you forgot the link on the full face model.
Seriously, that is something I can see coming in very handy!
Sorry my friend, no links were provided on any.
Yepā¦. That full face mask could come in real handy from time to time. I just use my half respirator & a face shield in those situations now. BUT that combo is awkward & clumsy. :person_facepalming:
Yeah, I wouldnāt suggest he pass them on at that price, especially since he has to do all the re-packing and shipping. I also donāt like the idea of GB participants paying for ALL the springs, leaving so many extras that are āfreeā. Iād say that somewhere in the middle is a fair price, but I donāt pretend to know what that is. :zipper_mouth_face:
Heās not going to get stuck holding extraās. I promise you that. Several of us here will up our ante in the long game and there wonāt be anything left. By the time that all getās sorted out and he seeās what is left Iāll know if I can take an extra hundred, or two. Some otherās will do the same thing, problem solved.
If this were tax return time I might be prone to buy a thousand myself. Of course, itās not, monies are all more tightly controlled right now and we have to start thinking about Christmas soon. (I know, right?)
Exactlyā¦. :+1:
WELLā¦ā¦ you could always get yourself a thousand or two & use them as stocking stuffersā¦. your stocking of course.
Maybe give the ālittle womanā a thousand tooā¦ā¦. hide a piece of jewelry for her in the springs & you might actually get away with that. .
indeed, if there are some left over I could easily order quite a few more myself. Heck if I have the money I plan to order extras as it is. Just waiting for things to settle down so I can see how much I can afford.
My initial request (20+20) was based on my available hobby funds, but if the price drops from the original estimate or ther are some surplus springs Iād love to get a few more. The prospect of never bypassing another spring is very appealing.
Iām sorry I havenāt read this thread, just post 1.
I wanted to ask if the large spring is going to be 7 mm on the top and 9 mm on the bottom? Typically you would want to get a smaller top so that you have more of a tapered shape. This will allow the spring to partially compress into itself allowing for a shorter compressed height and allowing a wider range of battery lengths to fit. When the spring is shaped more like a cylinder you just donāt get as much compression from it.
If this has already been discussed, just ignore my post above. Thanks
OK then.
You are lucky that I will only order the samples Thursday.
Yepā¦ from the OP.
- - Spring upper diameter: 7mm
- - Spring base diameter: 9mm
- - Spring thickness: 1mm
- - Spring height: 12mm
- - Plating: Zinc plating
No one in 180 posts has suggested to make the big spring have a 5mm top diameter?
Doing so might allow an extra millimeter or two longer battery to fit.
Itās something to think about (assuming the company is capable of doing it).