Wire diameter is bigger then 12 and hot wound. The ends are closed. But made by different technology. Grinding or tapering. And they are also shot peened both.
In my opinion there could be just bigger decarburization in case of tapered ends cause of one more heating. And then lower fatigue life...
I measured lateral rate of those two springs and compared them. Rate of springs with tapered ends was lower which quite suprised me.
So in my opinion lateral characteristic has more to do with design of end coil (I mean the gap between end of spring and active coil and of course the cross coil).
Can somebody tell me which ends (tapered or grinding) are better for compresson coil spring for rail industry? I know that standards dont deal whit it. But can it make differences in fatigue life, lateral characteristic of springs or so...?
