Why does thickness of keycaps matters?

[ctm]

I keep hearing people talk about *thick* PBT caps. I understand that PBT feels differently than ABS, but why does thickness matters? How and why it changes the feeling?

[CPTBadAss]

Thicker keycaps changes the density and mass of the keycap giving a different feeling. I like how thick doubleshot ABS caps feel. Just a personal preference thing.

[mashby]

It also changes the sound of your typing. Thinner key caps tend to have a higher pitch.

[tp4tissue]

NOT all thicker keycaps  weigh more..


For example.. the IMSTO thick pbt caps weigh the same amount as the kbc thin pbt caps.

[Melvang]

Thicker keycaps changes the density and mass of the keycap giving a different feeling. I like how thick doubleshot ABS caps feel. Just a personal preference thing.

Wouldn't thickness only change weight, material would change density

[CPTBadAss]

Density or Rho = mass / volume.

So the caps' volume and mad can change right?

[Oobly]

Thicker cap = more mass. More mass = different resonant frequency and higher moment of inertia. Higher moment of inertia = different feel. Different resonant frequency = different sound.

I really like heavy caps. Heaviest caps I've found so far are SA profile doubleshots, despite being ABS.

Density is a fixed material property. If you change the volume, the mass changes in proportion, so the ratio remains the same. POM is densest, then PBT (quite close to POM's value), then ABS. So the same volume keycap made with POM or PBT will be heavier than one made from ABS.

IMSTO thick PBT home row caps may weight the same as KBT "thin" (actually medium thickness) home row caps, but I'm sure the top row caps are heavier. Difference is due to profile.

[Bromono]

I also don't like the LEDs to shine through my caps. So the thicker the better.

[ViciousWhiskers]

Density or Rho = mass / volume.

So the caps' volume and mad can change right?

Density stays the same.

[noisyturtle]

There is such a thing as too thick though.

[Novus]

There is such a thing as too thick though.

 

[njbair]

[Binge]

Show Image

You have such value now.

[Giorgio]

Not only the thickness, also the shape is very important. Some keycaps amplify the sound of the switch acting like a bell.

[LennyRhys]

TBH I'm not sure I get the thickness thing being a component of feel.  I'm currently using thick PBT caps on MX blues and there's no difference in feel between them, thin ABS (SP) and original cherry doubleshots, which are THICK.  The biggest difference is the sound.  To get a noticeable difference in feel I have to use a different switch on a different board (I've got blues, browns & blacks, also an ALPS board and had a Model M too).

When you factor in the resistance of the spring vs the actual weight difference between the different keycap types, probably about half a gram, it translates to approx 1-2% of the actuation force.  The science is more complicated than that of course, because the spring's resistance isn't linear; but simply put, I don't think that an extra half gram of plastic on a 50g spring feels "different."

[Giorgio]

Sound is the main difference, yeah. A huge difference.

......  The biggest difference is the sound. ....

[Oobly]

TBH I'm not sure I get the thickness thing being a component of feel.  I'm currently using thick PBT caps on MX blues and there's no difference in feel between them, thin ABS (SP) and original cherry doubleshots, which are THICK.  The biggest difference is the sound.  To get a noticeable difference in feel I have to use a different switch on a different board (I've got blues, browns & blacks, also an ALPS board and had a Model M too).

When you factor in the resistance of the spring vs the actual weight difference between the different keycap types, probably about half a gram, it translates to approx 1-2% of the actuation force.  The science is more complicated than that of course, because the spring's resistance isn't linear; but simply put, I don't think that an extra half gram of plastic on a 50g spring feels "different."

The mass of the cap definitely affects the feel, particularly when typing fast. "F=ma" and all that (the force required to accelerate a mass with a particular acceleration is proportionate to the mass). Spring force is only one factor. Heavy keycaps have more "reaction force" and momentum.

You won't feel a difference if you're just pressing them slowly.

Thin, light keycaps just don't do it for me. They feel cheap and insubstantial. Thick, heavy caps have that high quality solid feeling to them. Love my 2g SA profile caps

[LennyRhys]

I still don't think that it's the increase in mass that's making the caps feel different - if SA caps "feel different" from OEM, surely it's because they're SA and not OEM, lol! 

If anybody wanted to go down the route of comparing the feel of keycaps of varying mass, they'd have to use keycaps of exactly the same profile with the same texture etc. otherwise the results would be compromised IMO.  I have tons of SA caps from a grab bag, the thickest and heaviest fookers I have ever seen, and I still don't feel any difference in actuation until I move to a different switch (I currently have them on an Access board with MX blacks - great partnership).  They certainly feel different to type on because they are higher, and they have a different surface shape and texture.  For comparison, going from MX browns back to MX blues feels different in actuation... but that's because there's a difference of 5cN in actuation force, which is a jump of more than 10% in resistance (45cN to 50cN).  I still don't see how jumping less than 1g in keycap weight can feel different, somewhere between 1-2%.

The maths tells us only what it can - that there is a difference in weight/mass/resistance/acceleration etc.; but it doesn't tell us that the difference is perceptible.

[tbc]

people type differently.

some people intentionally smash down as fast as possible.

some people slow down after actuation but still bottom out.

others still notbottom.

[njbair]

I don't think there's as big a difference between sound and feel as is implied in this thread. One time I had this weird ear infection where I could hear most things just fine but I couldn't hear any low frequencies (roughly 300Hz and below, if I had to guess). It was like that for about a week.

I can remember starting my car that week. Every time I had to double check that it started because I couldn't hear the low rumble of the engine turning over. More noticeably, I couldn't feel the engine rumble. It's hard do describe something like this, but you feel stuff like that in your chest, but when I lost low frequency hearing that feeling was gone.

So anyway, this is probably different for everybody, but those saying the caps feel different are probably just referring to this same phenomenon, while those who say it's just a sound difference maybe aren't as sensitive to this kind of thing.

[Lu_e]

In regards to weight; IMSTO thick PBT seem really thin on top, they seemed thinner than even a PBT SignaturePlastics DCS top. Pretty noticeable when its a white cherry profile IMSTO key on a red LED. But with that method a bit of it comes down to translucency/light dissipation of different varieties of PBT plastic.'

Only way to know for sure would be to cut them in half and measure the keycap 'pad' area thickness. But to me; the IMSTO thick cherry profile PBT seemed pretty thin on top.

edit; Just searched for some pictures of this I had when experimenting but they're attached in a Private Message from 'October 29, 2012' and are not there anymore. :\

[Oobly]

I still don't think that it's the increase in mass that's making the caps feel different - if SA caps "feel different" from OEM, surely it's because they're SA and not OEM, lol! 

If anybody wanted to go down the route of comparing the feel of keycaps of varying mass, they'd have to use keycaps of exactly the same profile with the same texture etc. otherwise the results would be compromised IMO.  I have tons of SA caps from a grab bag, the thickest and heaviest fookers I have ever seen, and I still don't feel any difference in actuation until I move to a different switch (I currently have them on an Access board with MX blacks - great partnership).  They certainly feel different to type on because they are higher, and they have a different surface shape and texture.  For comparison, going from MX browns back to MX blues feels different in actuation... but that's because there's a difference of 5cN in actuation force, which is a jump of more than 10% in resistance (45cN to 50cN).  I still don't see how jumping less than 1g in keycap weight can feel different, somewhere between 1-2%.

The maths tells us only what it can - that there is a difference in weight/mass/resistance/acceleration etc.; but it doesn't tell us that the difference is perceptible.

I can do some math to show you the difference is significant at high accelerations, but I don't need to. I KNOW they feel different from experience. Just compare what people are saying about GMK cherry doubleshots vs DCS. Almost identical profile, both doubleshots, same material.

[davkol]

No need to compare DCS and Cherry. Cherry Corp. themselves have made both thin and thick PBT caps.

[Oobly]

No need to compare DCS and Cherry. Cherry Corp. themselves have made both thin and thick PBT caps.

Ah yes, can't believe I forgot about those. I have some of the thin ones and I really don't like them compared to GMK.