PSA: Custom Korean springs have different force curve than Cherry springs.

[Hyde]

I want to start a new thread to get some awareness in case people fall into the same situation as me:  https://geekhack.org/index.php?topic=90205.0

As it was discussed in the other thread, I wanted something a little bit heavier than MX Red so I bought custom 62g Korean spring only to find out the force curve is different enough to bug me.

Cherry MX Red:  The force starts medium, ramp up steady and finish with slight increase in force.

62g Koreasn Spring:  To me this feel like it start off LIGHTER than MX Red, then ramp up HEAVIER than MX Red in the end.

So while it does accomplish what I want with a heavier spring but the light initial start bugs me.  At this point I feel like I'm actually happier with MX Red spring (though for this project I modded off MX Black, but I have other MX Red keyboards).

62g is very popular for ergo clear mod, I think with tactile switch it balance the initial force a bit so might have worked better.  But on linear switch I didn't think it was a good match.

So for those out there that want something a little bit heavier than MX Red.  This is NOT the solution.

From other threads it sounds like Gateron Yellow or Outemu Light Spring is suppose to be the solution for this.  I wish I knew this before de-soldering 104 switches.

Oh well I think in the mean time I'll just stick to stock Cherry switches and Topre.

[tp4tissue]

Magic springs 2017

[Giorgio]

Haata has done the most interesting work on springs. It's on deskthority

[Daniel Beardsmore]

There's nothing magic about it. The initial force is called "preload" and it depends in part on the length of the spring, i.e. how much is the spring compressed when the switch is in the rest position. The longer the spring, the more it has to be squashed to fit in the switch. A stiffer spring of the same length will also raise the preload, so then you need to shorten the spring to bring down the preload.

Linear switches are a simple y = mx + c graph, where m relates to your spring stiffness and c is the preload. Hooke's Law tells you about the spring itself.

You simply need the specifications of the new springs to determine exactly what you're going to get. If you simply call a spring "65 g", what does that even mean?

[Giorgio]

What's the easier way to shorten a spring? I need to shorten it by about 1mm, which could translate in cutting 0.5 inches of wire.

[tp4tissue]

There's nothing magic about it. The initial force is called "preload" and it depends in part on the length of the spring, i.e. how much is the spring compressed when the switch is in the rest position. The longer the spring, the more it has to be squashed to fit in the switch. A stiffer spring of the same length will also raise the preload, so then you need to shorten the spring to bring down the preload.

Linear switches are a simple y = mx + c graph, where m relates to your spring stiffness and c is the preload. Hooke's Law tells you about the spring itself.

You simply need the specifications of the new springs to determine exactly what you're going to get. If you simply call a spring "65 g", what does that even mean?

Magic,  Got it.. Thanks Daniel

[FrostyToast]

IIRC, sprit springs intentionally had "soft starts" as a part of their designs starting with the v2 springs.
I would like to see what different Korean makers do for their springs.

[Hyde]

There's nothing magic about it. The initial force is called "preload" and it depends in part on the length of the spring, i.e. how much is the spring compressed when the switch is in the rest position. The longer the spring, the more it has to be squashed to fit in the switch. A stiffer spring of the same length will also raise the preload, so then you need to shorten the spring to bring down the preload.

Linear switches are a simple y = mx + c graph, where m relates to your spring stiffness and c is the preload. Hooke's Law tells you about the spring itself.

You simply need the specifications of the new springs to determine exactly what you're going to get. If you simply call a spring "65 g", what does that even mean?

Hmmmm interesting to know, so for instance if I want a consistent force through out as much as possible, I'd want a longer spring then?  Is that right?  Like if I want my preload to be similar weight as my bottom out force.

IIRC, sprit springs intentionally had "soft starts" as a part of their designs starting with the v2 springs.
I would like to see what different Korean makers do for their springs.

lol damn it does that mean I was better off with the V1 spring then?  I noticed on the website for certain weight they have category such as 50g and 55g are Quick Arrow Edition, 60g, 62g, and 65g are The Ergo Edition, 68g and 72g are The Vintage Black Edition.

Does that mean different edition have different properties?

lol damn I still wish I knew about this before desoldering 104 switches. 

[Darksair]

Hmmmm interesting to know, so for instance if I want a consistent force through out as much as possible, I'd want a longer spring then?  Is that right?  Like if I want my preload to be similar weight as my bottom out force.

Yes, ideally you'll need a very long spring with very small spring constant (a very soft spring) and an initial position that is very far away (heavily compressed) from the free position.

Now I feel like a proper nerd.

[Puddsy]

this isn't new information

we've known this since people figured out cherry measures weights at actuation and koreans measure springs at bottom out

[davkol]

Isn't this, like, high-school physics? O_o

I guess we're dealing with damage done by ripster's ripometer or whatever he calls putting weights on keys until they compress. His whole "keyboard science" is a huge load of pseudo-intellectualism.

[keytohopiness]

I hate pseudo-intellectuals.  I prefer Trump science.

[tp4tissue]

I hate pseudo-intellectuals.  I prefer Trump science.

Trump best president..

[davkol]

I hate pseudo-intellectuals.  I prefer Trump science.

That escalated quickly.

I, for one, would prefer neither pseudo-intellectualism, nor anti-intellectualism.

[Hyde]

this isn't new information

we've known this since people figured out cherry measures weights at actuation and koreans measure springs at bottom out

Yes Cherry MX Red bottom out around 60g and the Korean spring bottom out around 62g.  So I was expecting a little bit heavier but the force curve is different so it actually feels entirely different.

Isn't this, like, high-school physics? O_o

I guess we're dealing with damage done by ripster's ripometer or whatever he calls putting weights on keys until they compress. His whole "keyboard science" is a huge load of pseudo-intellectualism.

lol yeah but I guess when they sell spring they don't list things like spring length and how many coils so unfortunately I had to find out the hard way.