I just have a quick and pretty n00b question about Progressive springs.
I have build a few switches using these [usually Spirit 63.5 and 68P] and I am placing the tightly-coiled part of the spring towards the top.
This issue was discussed here previously, as seen in this photo of the ‘correct’ orientation:
So is this the ‘correct’ orientation?
It’s such a basic question, but there’s surprisingly little documentation about this, even on the sites that sell the springs.
I’m pretty sure it doesn’t matter which direction it’s in.
SPRiT himself says:
No Polarity on Progressive springs.
According to the Newtonians, Fab = - Fba
You can say this simply, “When you press the lighter end, the heavier end will be pressed by exactly the same pressure. vise versa.”
Nebulant also says the orientation doesn’t matter.
https://www.instagram.com/p/CKU-lO1HFti/
Yeah, my understanding was that the physics say orientation of the spring shouldn’t matter.
But apparently there is a ‘right’ way, so I wanted to check first.
I have a note that says “tight coils up” on my lube station to remind me. I’d recommend being consistent if you’re making a batch, to make the switches as consistent as possible. That said, I don’t think it matters.
I’ve done builds with progressive springs having the tighter coils down before I knew tighter coils up was considered “proper install”. Functionally & feelwise you can tell no difference TBH. Although I’d recommend doing the “proper install” as there has to be some reason behind it. Like maybe the springs will degrade quicker or something? Who knows, so i figure it’s best to follow the commonly accepted install method.
Total conjecture: I wonder if it might make a difference in context of tactiles - would the interplay between spring and leaf tension be any different depending on the orientation? I feel like math would say “no” but I wonder if the tight coil being closer or farther away from the secondary tension source would have any effect. This is why I really want a device to measure force-curves
Many months ago I was playing around with TT MP springs and tactiles, and I could have sworn it made a minor difference in the character of the throw - but that could have easily been confirmation bias at work. Haha dammit now I’m more curious than I was before…
Well, Nebulant’s force curve linked above is of a tactile switch right (Holy GSUS)? But now I’m curious how the practice of tighter coils up originated. There should be a keyboard mythbusters series 
It shouldn’t, but I feel a difference but it might be a placebo thing. 
Orientation shouldn’t matter but some housings have grooves for springs that fit one orientation better than the other
I have some progressive spirit springs coming. Based on everyone’s answers, orientation doesn’t matter for feel. But is there any benefit of placing them with the same orientation? What if there is spring crunching noise? We want them to compress and make noises at the same relative height, right?
Anytime I’ve used progressive springs I’ve always made sure they were all aligned the same way & put the tighter coils up, looser coils down since that is they way I’ve found most recommended for them. Also don’t expect a big difference in feel compared to regular linear springs. IME progressive springs do definitely give a lighter actuation weight for any given bottom out weight, but the keypress feel is largely the same as linear springs. Unless you are getting really heavy progressive springs I suppose. MX clear & Halo/Hako springs are the only I’ve ever used that really have a “ramping up” feeling as you get closer to bottom out. Although if you look at the springs for those switches all three have ones with evenly spaced coils, not sure what that really says about “progressive” springs. Just relaying my experience with them.
Theoretically it shouldn’t matter, but if u have the spring between thumb and index finger and press then turn it around it will feel different 🤷
These are linear springs, with high K, normal or reduced length: the ramp up in force is steeper, but still linear.
Progressive springs have a variable K, the force curve is not linear (but curves “up”).
I have some KTT Sea Salt lemon coming. They got my attention because divinkey advertised them as having 13mm progressive springs. But I wouldn’t be surprised if what they mean is just shorter springs(constant k, steep linear force curve).
While there are many aftermarket long springs, I am surprised by the lack of options for short springs(shorter than the 14mm standard) because both the stock springs in MX clear and MX black are shorter than 14mm. Sprit progressive fills this gap but like you said, their force curve are convex.
