Thick PBT - Heavy Keypresses?

[Linkbane]

So I recently got the Yellow edition Shine 3 in the mail (with Blues), but for some reason, the feel is really heavy, and feels completely different from a TK which I have with thin PBT caps.
Every keypress feels like it takes so much more force, pretty much the same as Greens. Is that a something that thick PBT is supposed to feel like, because if so I may be forced to switch to my white caps for alphabet keys.
Thanks for any help.

[terran5992]

Must be a problem specific to the ducky yellow.

Thick PBT feels awesome to me

[SpAmRaY]

Maybe they got their springs mixed up in assembly.

Maybe test with nickles.

[Linkbane]

Maybe they got their springs mixed up in assembly.

Maybe test with nickles.

Good idea, I was thinking of doing that. Will post results in a bit.

[Fullcream]

I do not believe that a thicker key cap would cause an increase in force required to depress a key. Thick key caps are made of more material, meaning there is more weight initially resting on the spring therefore very slightly reducing actuation and bottom out force. Possibly has wrong springs in the switches.

[tbc]

CM QF TK and ducky shine 3.  I have both of those in blues and they feel completely different.

I've always been told that different boards with the same switches feeling different is completely normal.

My TK is very  stereotypical blue; crisp, loud click with hard landing.  Shine 3 feels like there is medium to thicl viscosity lube inside; your press has to fight both the spring AND the physical mass of the lube.

[1pq]

You seem to love super light switches--why don't you mod it with some 45 or 55g springs from originative? I suppose desoldering all those LEDs would be a pain though...

[rowdy]

Wrong spring in the switches?  Isn't is likely that Ducky just buy a few hundred thousand switches from Cherry and solder them into their keyboards?  And why would Cherry put the wrong spring in the switches?

FWIW I have two Ducky Shine (version 1) with MX blues and they both feel different.

[SpAmRaY]

Wrong spring in the switches?  Isn't is likely that Ducky just buy a few hundred thousand switches from Cherry and solder them into their keyboards?  And why would Cherry put the wrong spring in the switches?

FWIW I have two Ducky Shine (version 1) with MX blues and they both feel different.

  /wasnotsrs

[Oobly]

Heavy caps do feel different on the same switches, even on the same board. They have more mass and thus more momentum, so need a bit more force to accelerate, but not much (at low speeds). For someone like me who types relatively slowly, it's more a different feeling than anything else, doesn't feel like it needs much more force to press.

If you type really fast, though, it will need more force to press since the mass resists acceleration more the quicker you try to accelerate it (force=mass x acceleration).

I like light switches with heavy caps, gives a "quality" feeling IMO, but I may change my mind as I speed up. Perhaps try the thinner caps on one hand only, so you can get a feeling of them both at the same time.

[Linkbane]

Heavy caps do feel different on the same switches, even on the same board. They have more mass and thus more momentum, so need a bit more force to accelerate, but not much (at low speeds). For someone like me who types relatively slowly, it's more a different feeling than anything else, doesn't feel like it needs much more force to press.

If you type really fast, though, it will need more force to press since the mass resists acceleration more the quicker you try to accelerate it (force=mass x acceleration).

I like light switches with heavy caps, gives a "quality" feeling IMO, but I may change my mind as I speed up. Perhaps try the thinner caps on one hand only, so you can get a feeling of them both at the same time.

For typing, I much prefer the lighter caps. If I can't get used to the feeling in a bit, I probably will just switch over to the lighter caps so my speed doesn't suffer.
The feeling is certainly quality, just too heavy for me.

[SpAmRaY]

http://geekhack.org/index.php?topic=49458.msg1169437.msg#1169437

Post confirming NO lube and cherry direct stabilizers

[1pq]

Heavy caps do feel different on the same switches, even on the same board. They have more mass and thus more momentum, so need a bit more force to accelerate, but not much (at low speeds). For someone like me who types relatively slowly, it's more a different feeling than anything else, doesn't feel like it needs much more force to press.

If you type really fast, though, it will need more force to press since the mass resists acceleration more the quicker you try to accelerate it (force=mass x acceleration).

I like light switches with heavy caps, gives a "quality" feeling IMO, but I may change my mind as I speed up. Perhaps try the thinner caps on one hand only, so you can get a feeling of them both at the same time.

For typing, I much prefer the lighter caps. If I can't get used to the feeling in a bit, I probably will just switch over to the lighter caps so my speed doesn't suffer.
The feeling is certainly quality, just too heavy for me.

Just mod it to lighter springs, dude! Thick PBTs are the best feeling ever.

[1pq]

I've been using a Das III with blues for about a year, and I just got a filco today (also with blues). Typing on it made me think of your post: it's SO MUCH HEAVIER.
I think something that we often forget when typing on mx switches for a while is that they get significantly lighter with time (albeit very gradually--that's why you forget it). If you use your Ducky exclusively for a couple weeks, it will definitely start to lighten up.

[sprk]

I've been using a Das III with blues for about a year, and I just got a filco today (also with blues). Typing on it made me think of your post: it's SO MUCH HEAVIER.
I think something that we often forget when typing on mx switches for a while is that they get significantly lighter with time (albeit very gradually--that's why you forget it). If you use your Ducky exclusively for a couple weeks, it will definitely start to lighten up.

I agree. What OP is experiencing is probably brand new switches vs switches that have already gone through some use.

[tp4tissue]

you need around 10k to get it smooth.

[berserkfan]

agree with you

OP just needs to break in his switches. They all tend to feel rougher when new.

I've been using a Das III with blues for about a year, and I just got a filco today (also with blues). Typing on it made me think of your post: it's SO MUCH HEAVIER.
I think something that we often forget when typing on mx switches for a while is that they get significantly lighter with time (albeit very gradually--that's why you forget it). If you use your Ducky exclusively for a couple weeks, it will definitely start to lighten up.

I agree. What OP is experiencing is probably brand new switches vs switches that have already gone through some use.

[Vintage]

Interesting. I would think that thick PBT would feel lighter than thin. Although I can't say I noticed a significant difference between the heaviness of the switches when switching to thick PBT.

[Polymer]

They do...unless you're typing against the force of gravity..

Otherwise slightly more weight will be resting on the switch/spring which means it requires less force to press down on it. 

It could be the feeling of the thicker PBT or it could be the newness of the switches...

Have you tried swapping some keycaps to see? 

[tp4tissue]

Interesting. I would think that thick PBT would feel lighter than thin. Although I can't say I noticed a significant difference between the heaviness of the switches when switching to thick PBT.

no... weigh the thick pbt and the thin pbt.. they weigh the same.

I compared the imsto ones with the kbc pbt from ol'school

[Photoelectric]

Are the yellow PBT caps OEM profile or more like Cherry?  If the latter, that would explain the greater effort in actuation.  If both the yellow caps and your thin PBT are the OEM profile, then I don't know what it could be.

[Oobly]

They do...unless you're typing against the force of gravity..

Otherwise slightly more weight will be resting on the switch/spring which means it requires less force to press down on it. 

It could be the feeling of the thicker PBT or it could be the newness of the switches...

Have you tried swapping some keycaps to see?

Yes, the initial spring force is reduced a tiny amount, but it is not significant. Cherry MX light springs require 35g of force to start compressing from their resting state (due to being precompressed between the stem and casing). A single cap weighs far less than this (around 2g if I am not mistaken, and the difference is at most 1.5g) and thus will not really be noticed.

Its mass is more significant in terms of the force required to accelerate it. The mass of the stem + cap (unsprung weight with respect to the motive force) is significantly increased when switching from ABS to thick PBT.

What this all means is that if you press slowly, you will hardly notice a difference, but the quicker you press the more noticeable the kaycap weight difference will be (F=ma) and the more relative force is required.

I suspect, however, that the new vs old switches is more of a factor here. I didn't take that into consideration initially.

[Polymer]

They do...unless you're typing against the force of gravity..

Otherwise slightly more weight will be resting on the switch/spring which means it requires less force to press down on it. 

It could be the feeling of the thicker PBT or it could be the newness of the switches...

Have you tried swapping some keycaps to see?

Yes, the initial spring force is reduced a tiny amount, but it is not significant. Cherry MX light springs require 35g of force to start compressing from their resting state (due to being precompressed between the stem and casing). A single cap weighs far less than this (around 2g if I am not mistaken, and the difference is at most 1.5g) and thus will not really be noticed.

Its mass is more significant in terms of the force required to accelerate it. The mass of the stem + cap (unsprung weight with respect to the motive force) is significantly increased when switching from ABS to thick PBT.

What this all means is that if you press slowly, you will hardly notice a difference, but the quicker you press the more noticeable the kaycap weight difference will be (F=ma) and the more relative force is required.

I suspect, however, that the new vs old switches is more of a factor here. I didn't take that into consideration initially.

No..your calculation is not taking into account GRAVITY.  The caps would fall without any help from anyone..the spring is holding it up.

Simple way to show this is looking at how much weight it would take to push a particular key down.

So assume a 2g difference in keycaps (it probably isn't even close to that but lets just say).

Assuming you testing with the lightest keycap and the switch was fully depressed at 60g of weight...and then put the heaviest keycap on (2g heavier) it would take 58g of weight to fully depress the key...

[Oobly]

They do...unless you're typing against the force of gravity..

Otherwise slightly more weight will be resting on the switch/spring which means it requires less force to press down on it. 

It could be the feeling of the thicker PBT or it could be the newness of the switches...

Have you tried swapping some keycaps to see?

Yes, the initial spring force is reduced a tiny amount, but it is not significant. Cherry MX light springs require 35g of force to start compressing from their resting state (due to being precompressed between the stem and casing). A single cap weighs far less than this (around 2g if I am not mistaken, and the difference is at most 1.5g) and thus will not really be noticed.

Its mass is more significant in terms of the force required to accelerate it. The mass of the stem + cap (unsprung weight with respect to the motive force) is significantly increased when switching from ABS to thick PBT.

What this all means is that if you press slowly, you will hardly notice a difference, but the quicker you press the more noticeable the kaycap weight difference will be (F=ma) and the more relative force is required.

I suspect, however, that the new vs old switches is more of a factor here. I didn't take that into consideration initially.

No..your calculation is not taking into account GRAVITY.  The caps would fall without any help from anyone..the spring is holding it up.

Simple way to show this is looking at how much weight it would take to push a particular key down.

So assume a 2g difference in keycaps (it probably isn't even close to that but lets just say).

Assuming you testing with the lightest keycap and the switch was fully depressed at 60g of weight...and then put the heaviest keycap on (2g heavier) it would take 58g of weight to fully depress the key...

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

[Polymer]

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

I see where you're going with this but I don't think it is correct.  Are you pressing faster than gravity?  I don't think so..

In .05 seconds so basically 20 presses in 1 second (1200 characters in a minute) gravity would take it 1.22cm which is 12.2mm.  3 times further than how far the keys go.  To travel 4mm it would take .028 seconds.  So lets just say 35 presses per second or 2100 cps. 

Since you aren't outracing gravity then whatever force you need to press overcome the spring doesn't require you to move the extra mass you're talking about.  Even if the keycap was 100kg and required an additional 60g to press down, it would move quickly and without you needing to accelerate the mass..gravity would be doing that for you...

[Oobly]

It's all about the forces. Gravity is always acting on the cap to produce mass_cap*9.81N downward force. The spring is also always acting on the cap to produce 0.035*9.81N of upward force at the top of the movement. The top of the switch therefore exerts 0.035*9.81 - mass_cap*9.81 N of reactive force to maintain equilibrium. The force gravity exerts is always overcome by the spring force, and by a large excess, too. The spring force increases with downward compression, the force exerted by gravity remains the same. So this reduces the relative effect of gravity as the keypress progresses.

Accelerations are always the result of forces acting on bodies, not the other way around. You are accusing me of ignoring gravity, but I am accusing you of ignoring the much stronger spring force.

Assuming a fast keypress is 0.02s, the acceleration is 20m/s² and requires roughly 0.04N or around 4g pressure on top of the spring resistance force. Admittedly, it's not a lot, but the accelerative force required will increase exponentially with the speed and linearly with the cap mass. About twice the decrease in pressure due to gravity using these values. A lighter cap will require only around 1g accelerative pressure.

When in doubt, reduce it to a simple force diagram, apply Newton's laws and see what you get.

Anyway, the point is probably moot, since the effect the OP feels is most likely due more to new springs vs old, worn-in ones.

[Linkbane]

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

I see where you're going with this but I don't think it is correct.  Are you pressing faster than gravity?  I don't think so..

In .05 seconds so basically 20 presses in 1 second (1200 characters in a minute) gravity would take it 1.22cm which is 12.2mm.  3 times further than how far the keys go.  To travel 4mm it would take .028 seconds.  So lets just say 35 presses per second or 2100 cps. 

Since you aren't outracing gravity then whatever force you need to press overcome the spring doesn't require you to move the extra mass you're talking about.  Even if the keycap was 100kg and required an additional 60g to press down, it would move quickly and without you needing to accelerate the mass..gravity would be doing that for you...

You can't think of it like that. The method you're using in measuring keypresses isn't accurate because you're measuring keypresses per second in relation to speed of pressing. These two factors are completely unrelated. Someone who types at 20 wpm compared to me typing at 150 wpm might press the key for the same amount of time, but it is the time between presses that makes wpm.

[neunelfer]

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

I see where you're going with this but I don't think it is correct.  Are you pressing faster than gravity?  I don't think so..

In .05 seconds so basically 20 presses in 1 second (1200 characters in a minute) gravity would take it 1.22cm which is 12.2mm.  3 times further than how far the keys go.  To travel 4mm it would take .028 seconds.  So lets just say 35 presses per second or 2100 cps. 

Since you aren't outracing gravity then whatever force you need to press overcome the spring doesn't require you to move the extra mass you're talking about.  Even if the keycap was 100kg and required an additional 60g to press down, it would move quickly and without you needing to accelerate the mass..gravity would be doing that for you...

You can't think of it like that. The method you're using in measuring keypresses isn't accurate because you're measuring keypresses per second in relation to speed of pressing. These two factors are completely unrelated. Someone who types at 20 wpm compared to me typing at 150 wpm might press the key for the same amount of time, but it is the time between presses that makes wpm.

The time that each keypress takes is obviously also included...

I swear sometimes you post just so that you can say that you type at 150 WPM.

[Linkbane]

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

I see where you're going with this but I don't think it is correct.  Are you pressing faster than gravity?  I don't think so..

In .05 seconds so basically 20 presses in 1 second (1200 characters in a minute) gravity would take it 1.22cm which is 12.2mm.  3 times further than how far the keys go.  To travel 4mm it would take .028 seconds.  So lets just say 35 presses per second or 2100 cps. 

Since you aren't outracing gravity then whatever force you need to press overcome the spring doesn't require you to move the extra mass you're talking about.  Even if the keycap was 100kg and required an additional 60g to press down, it would move quickly and without you needing to accelerate the mass..gravity would be doing that for you...

You can't think of it like that. The method you're using in measuring keypresses isn't accurate because you're measuring keypresses per second in relation to speed of pressing. These two factors are completely unrelated. Someone who types at 20 wpm compared to me typing at 150 wpm might press the key for the same amount of time, but it is the time between presses that makes wpm.

The time that each keypress takes is obviously also included...

I swear sometimes you post just so that you can say that you type at 150 WPM.

Don't assume that people are full of themselves just because you might be. I'm giving a completely logical argument, unlike yourself.

[tp4tissue]

what increased mass are you guys talking about..

Those thick caps weigh the same...

[tbc]

how can they possibly weigh the same?

aren't they thicker on all 5 sides?

[tp4tissue]

how can they possibly weigh the same?

aren't they thicker on all 5 sides?

did you weigh them  ?... I DID....  LOL
the taller thin kbc-oem profile pbt weigh exactly the same as the cherry profile thick pbt

[Polymer]

Of course I am, I mentioned it is negligable. It reduces the pressure by maximum 2g throughout the press, which is NOT NOTICEABLE (around 5%). 2g is less than the variance between individual springs on a board.

The mass does, however, increase the force required to ACCELERATE the cap and stem by a significant percentage(>40%). So, if there is a difference in perceived force to actuate (and the individual in question types really fast), it's most likely going to be an increase in force due to the increased unsprung mass, not a decrease due to the static mass.

I see where you're going with this but I don't think it is correct.  Are you pressing faster than gravity?  I don't think so..

In .05 seconds so basically 20 presses in 1 second (1200 characters in a minute) gravity would take it 1.22cm which is 12.2mm.  3 times further than how far the keys go.  To travel 4mm it would take .028 seconds.  So lets just say 35 presses per second or 2100 cps. 

Since you aren't outracing gravity then whatever force you need to press overcome the spring doesn't require you to move the extra mass you're talking about.  Even if the keycap was 100kg and required an additional 60g to press down, it would move quickly and without you needing to accelerate the mass..gravity would be doing that for you...

You can't think of it like that. The method you're using in measuring keypresses isn't accurate because you're measuring keypresses per second in relation to speed of pressing. These two factors are completely unrelated. Someone who types at 20 wpm compared to me typing at 150 wpm might press the key for the same amount of time, but it is the time between presses that makes wpm.

That is true..someone typing 20wpm might press down as quickly as someone at 150wpm.

But I'm giving an example of how fast that really is.  To press down a keycap that quickly means you'd be able to move 35 keycaps down in 1 second.  It is just to put that speed into perspective. 

[Polymer]

It's all about the forces. Gravity is always acting on the cap to produce mass_cap*9.81N downward force. The spring is also always acting on the cap to produce 0.035*9.81N of upward force at the top of the movement. The top of the switch therefore exerts 0.035*9.81 - mass_cap*9.81 N of reactive force to maintain equilibrium. The force gravity exerts is always overcome by the spring force, and by a large excess, too. The spring force increases with downward compression, the force exerted by gravity remains the same. So this reduces the relative effect of gravity as the keypress progresses.

Accelerations are always the result of forces acting on bodies, not the other way around. You are accusing me of ignoring gravity, but I am accusing you of ignoring the much stronger spring force.

Assuming a fast keypress is 0.02s, the acceleration is 20m/s² and requires roughly 0.04N or around 4g pressure on top of the spring resistance force. Admittedly, it's not a lot, but the accelerative force required will increase exponentially with the speed and linearly with the cap mass. About twice the decrease in pressure due to gravity using these values. A lighter cap will require only around 1g accelerative pressure.

When in doubt, reduce it to a simple force diagram, apply Newton's laws and see what you get.

Anyway, the point is probably moot, since the effect the OP feels is most likely due more to new springs vs old, worn-in ones.

You're not taking into consideration the extra downward pressure already applied because of the greater mass.

Are you saying if we had a spring that required 60g to fully depress and a 59g keycap that it would take longer to bottom out?  Even though the required force to depress the key is 1g?  I don't think so...

Easiest way to test this to make it more obvious..

Press your shift key down...now add a few heavy coins on top..press down...it is a LOT easier to press down..it isn't even close...

Easiest way people can see for themselves..not sure why I didn't mention it earlier...

[Oobly]

It's all about the forces. Gravity is always acting on the cap to produce mass_cap*9.81N downward force. The spring is also always acting on the cap to produce 0.035*9.81N of upward force at the top of the movement. The top of the switch therefore exerts 0.035*9.81 - mass_cap*9.81 N of reactive force to maintain equilibrium. The force gravity exerts is always overcome by the spring force, and by a large excess, too. The spring force increases with downward compression, the force exerted by gravity remains the same. So this reduces the relative effect of gravity as the keypress progresses.

Accelerations are always the result of forces acting on bodies, not the other way around. You are accusing me of ignoring gravity, but I am accusing you of ignoring the much stronger spring force.

Assuming a fast keypress is 0.02s, the acceleration is 20m/s² and requires roughly 0.04N or around 4g pressure on top of the spring resistance force. Admittedly, it's not a lot, but the accelerative force required will increase exponentially with the speed and linearly with the cap mass. About twice the decrease in pressure due to gravity using these values. A lighter cap will require only around 1g accelerative pressure.

When in doubt, reduce it to a simple force diagram, apply Newton's laws and see what you get.

Anyway, the point is probably moot, since the effect the OP feels is most likely due more to new springs vs old, worn-in ones.

You're not taking into consideration the extra downward pressure already applied because of the greater mass.

Are you saying if we had a spring that required 60g to fully depress and a 59g keycap that it would take longer to bottom out?  Even though the required force to depress the key is 1g?  I don't think so...

Easiest way to test this to make it more obvious..

Press your shift key down...now add a few heavy coins on top..press down...it is a LOT easier to press down..it isn't even close...

Easiest way people can see for themselves..not sure why I didn't mention it earlier...

Nope, I'm saying it will take more force to accelerate it and that I AM taking the downward pressure due to gravity into account, or don't you understand basic mathematics and physics?

Sure, when pressing SLOWLY. When pressing really fast, the force required to accelerate a 59g cap would be around 1.18N = 120g on top of the 1g remaining spring force = 121g. Just do the math and stop arguing.

[Oobly]

how can they possibly weigh the same?

aren't they thicker on all 5 sides?

did you weigh them  ?... I DID....  LOL

Show Image

the taller thin kbc-oem profile pbt weigh exactly the same as the cherry profile thick pbt

Makes sense, different height profile. The same profile thick and thin WILL have different mass.

[Polymer]

Nope, I'm saying it will take more force to accelerate it and that I AM taking the downward pressure due to gravity into account, or don't you understand basic mathematics and physics?

Sure, when pressing SLOWLY. When pressing really fast, the force required to accelerate a 59g cap would be around 1.18N = 120g on top of the 1g remaining spring force = 121g. Just do the math and stop arguing.

Nope...it takes 1g...add another 1g of weight and it falls down by itself....Yet you're telling me it requires 121g of force? 

Your calculations are flawed.  You're not adding 60g of spring force on top of the mass..that is where you're screwing up your math.  The spring only has 1g of resistance left.

Here's another way of looking at it...Spring that requires 60g of mass to fully depress.  Keycap = 59g.  We both agree 1g more of mass = fully depressed.

If you drop 1g of weight from 1mm above the keycap onto the keycap...will that fully depress it?  Yes.  How much force are you getting by dropping 1g from 1mm of height?  or .5mm of height?  certainly NOT 121g. 

Again, put a bunch of coins on top of a switch...press on it..tell me which feels lighter..the one w/ the coins or the one w/o...it is easily the one w/ the coins.  Forget about your math..try it...tell me it isn't easier/lighter...I'd invite anyone else to do the same...

Easier to press = faster.

[Oobly]

The only thing I am ignoring is the increasing spring force as it compresses, whereas you are ignoring the fact that it takes force to accelerate a mass. The greater the mass or the acceleration required, the greater the force required.

You are considering only the statics of the system, not the kinematics.

[Polymer]

The only thing I am ignoring is the increasing spring force as it compresses, whereas you are ignoring the fact that it takes force to accelerate a mass. The greater the mass or the acceleration required, the greater the force required.

You are considering only the statics of the system, not the kinematics.

Seriously..you're wrong...look at the latest example..

60g required to fully depress a given spring.

59g keycap.

We agree 1g of extra mass would fully depress spring.

These would be facts in our example right?  A 60g Keycap would fully depress a spring that takes 60g to fully depress?  Is that right?  Yes.

So going to our 60g spring, 59g keycap example.

You grab a 1g weight.  Drop it from .000001mm away from the top of the keycap.  Or any small distance, 1mm if it makes it easier. 

Do we agree the spring would fully depress?  Yes.

Now calculate the force generated by dropping a 1g weight from 1mm away...it doesn't generate a whole lot of force does it?

[Linkbane]

The only thing I am ignoring is the increasing spring force as it compresses, whereas you are ignoring the fact that it takes force to accelerate a mass. The greater the mass or the acceleration required, the greater the force required.

You are considering only the statics of the system, not the kinematics.

Seriously..you're wrong...look at the latest example..

60g required to fully depress a given spring.

59g keycap.

We agree 1g of extra mass would fully depress spring.

These would be facts in our example right?  A 60g Keycap would fully depress a spring that takes 60g to fully depress?  Is that right?  Yes.

So going to our 60g spring, 59g keycap example.

You grab a 1g weight.  Drop it from .000001mm away from the top of the keycap.  Or any small distance, 1mm if it makes it easier. 

Do we agree the spring would fully depress?  Yes.

Now calculate the force generated by dropping a 1g weight from 1mm away...it doesn't generate a whole lot of force does it?

Polymer, you need to consider more than the obvious. Yes, perhaps moving something straight down might require less force to go down, but it takes a greater impulse force to move it.

[Polymer]

Polymer, you need to consider more than the obvious. Yes, perhaps moving something straight down might require less force to go down, but it takes a greater impulse force to move it.

The problem is there is an equilibrium created by the spring and the keycap.  In this case a 60g spring and 59g keycap.  Once you break that equilibrium, it'll hit bottom just with gravity.  You aren't moving a keycap in space.  You aren't typing upsidedown (if you are it would take more effort).

In our example..if you drop a 1g weight from a height of 0000001mm it'll cause the spring to fully depress.  But if you calculate the force that generated, it isn't a lot. 

Same reason why if a huge boulder (1000kg) can barely be held in place by something but a slight force can bump it and cause it to fall down.

Try the real life example...stack a bunch of nickels on your shift key...press it...easier/faster to press than w/o them right? 

[sprk]

Sure, when pressing SLOWLY. When pressing really fast, the force required to accelerate a 59g cap would be around 1.18N = 120g on top of the 1g remaining spring force = 121g. Just do the math and stop arguing.

Your math is terribly wrong.

Caveats

1) Standard gravity - 9.806 m/s²
2) Switch actuation point - 60g
3) Weight of key - 59g
4) Using an mx blue, the outer part of the stem measures - 3.6mm
5) For simplicity I'm depressing one key a second

Calculations

Acceleration

a = v_f - v_i / t

a = 0.0036m/s / 1s

a = 0.0036 m/s²

Force

If the actuation required for the switch is 60g, a 59g key would require an extra gram on top to collapse said switch. Ergo, for simplicities sake, we need to move that gram AT MOST 3.6mm for actuation.
 
f = ma

f = 0.001kg * 0.0036m/s²

f = 0.0000036N

Kilopond time

1N ≈ 0.10197 kp

0.0000036N = 0.00000036709 kp or kgf

Adjusting to grams gives us a grand total of 0.000367098 gf (taking into account gravity and a fully vertical position)

Conclusion

It takes a lesser amount of gram force than 1g to move a 59g key to actuation point on a 60g switch. Gravity at play here. In reality it would require even less force because the switch does not require being depressed completely, and it would require a bit more force for such actions at common typing speeds. It is still a long way from 121 grams of force to actuate a key in the latter case.

In reality it's more complicated than this, since we do have to calculate various other force vectors, the actual distance to actuation, etc. But most def a higher weight on top of the switch will make it easier to depress, not harder.

Edit: Grammar and formating.

[Oobly]

Firstly your caveats are incorrect (actuation point is around 2mm, which results in about 49g pressure: http://geekhack.org/index.php?topic=46449.0 AND you're using 1 press per second, which is practically static, whereas my calculations are based on VERY RAPID KEYPRESSES, since the OP types really fast), which results in your acceleration being incorrect for the case we are examining.

The point is that if you type VERY slowly, a heavy keycap will require less pressure to reach actuation (in fact, close to the keycap weight difference, although this will be hardly noticeable due to factors discussed below), but if you type fast it will require more due to the force required to accelerate it. The break-even point is probably around the average typing speed, which is not really all that fast.

Additionally, spring pressure reduction due to mass is not as easily felt as reluctance to accelerate due to the same incease in mass. The keys "feel" slow to move.  One reason for this is the small distance required for the spring force to increase sufficiently to cancel out the cap mass difference (0.1-0.2mm). Another is simply the way we are wired and how we detect subtle differences.

If you use a=20m/s² which is close to the actual use case, you arrive at a much higher force required to accelerate the cap (almost 120g for our impractical extreme case, but roughly equal to twice the cap mass in any case). The quicker you wish to depress the key, the more the increase in force, since s=ut+1/2 at² As t decreases, a increases parabolically and thus F increases parabolically with a.

To do this calculation properly (including the spring force increase with compression) will require calculus and I'm afraid I just don't have the time to spend doing complex calculations for a pointless argument, which should be clear to anyone with a decent education.

You could think of it this way: If 2 cars have the same engines, but one is lighter, which will accelerate quicker? Which will feel more "sluggish"?

[Polymer]

You could think of it this way: If 2 cars have the same engines, but one is lighter, which will accelerate quicker? Which will feel more "sluggish"?

Terrible analogy..If this was moving mass in space, you'd have an accurate one.

VERY RAPID keypresses won't be faster than gravity..we've already determined that.  If you dropped an object the amount of time for it to go 4mm was .028s. 

I should have caught this earlier but you are accelerating the object faster than gravity...in which case yes, the mass will create an issue..

But as I'm demonstrating, people aren't pressing the key faster than gravity...if a person could press a key 4mm in .02s you'd be pressing 50 keys in a second..or that is how fast you'd be doing it..that isn't correct.

Seriously though..just test it yourself...did you try putting coins on the shift key?  Did you try pressing it down quickly?  Are you really saying it was slower than just pressing it normally?

[Oobly]

Here's another little calculation, using realistic figures. Let's assume you apply 60g of force (enough to compress the spring without a cap and stem) and the force is the same through the movement:

Force required to bottom out spring = 60g
Keycap weight = 1g

Force of spring acting upwards at top of movement = 35g

So we have a starting condition of 35g upward force, 61g downward = 26g net downward force on the cap (finger force + gravity - spring force). Convert to Newtons = 0.255N

Applying F=ma we get
0.255N = 0.01kg * a
Therefore a= 25.5m/s²

That's the initial acceleration on a light cap.

For a heavy cap, applying the same calculation using the same finger force:

Cap weight = 2g

= 62g downward force, 35g upward = 27g net downward force = 0.265N

So 0.265N = 0.02kg * a
Therefore a = 13.24m/s²

That's close to half the acceleration experienced by the lighter cap. So you have to apply more force to get the same acceleration. Does that make it clearer?

Let's find out how much more force is needed to obtain the same acceleration:

F = 0.02g * 25.5m/s² = 0.51N = 52g

52g + 35g - 2g = 85g

So 85g of finger force is required to get a 2g cap to move as quickly as a 1g cap with 60g.

Please let me know if there is something I have missed in my calculations, but please also take a good look first.

[Polymer]

All of your calculations involve pressing the cap faster than the force of gravity...which isn't happening...I think we've determined already that the speed that you're using is wrong..

You still haven't explained why that 1g weight on a 59g cap would still depress the spring..even dropped from .00000001mm and yet still somehow needs a huge amount of force to do so..and it would depress at the speed of gravity..

And really, have you even tried this yet?

[Oobly]

All of your calculations involve pressing the cap faster than the force of gravity...which isn't happening...I think we've determined already that the speed that you're using is wrong..

You still haven't explained why that 1g weight on a 59g cap would still depress the spring..even dropped from .00000001mm and yet still somehow needs a huge amount of force to do so..and it would depress at the speed of gravity..

And really, have you even tried this yet?

Are you serious or just trolling?

You still haven't accepted Newtons laws. If you find a flaw in my previous post, please let me know what it is. It shows quite clearly that using enough force to bottom out (using constant force), the initial acceleration of a light cap IS more than 1G, ie more than gravity. More than twice as much, in fact (25.5m/s², or 2.6G). Even with a 2g cap, the initial acceleration is more than 9.81m/s² (13.24m/s²).

About the 59g, 1g thing, it WILL go down, but it won't go QUICKLY.

It's just as Linkbane says, the impulse required is larger for a heavier cap and grows parabolically for an increase in desired "quickness". You are not factoring this in at all, since you are doing static calculations only.

[Polymer]

All of your calculations involve pressing the cap faster than the force of gravity...which isn't happening...I think we've determined already that the speed that you're using is wrong..

You still haven't explained why that 1g weight on a 59g cap would still depress the spring..even dropped from .00000001mm and yet still somehow needs a huge amount of force to do so..and it would depress at the speed of gravity..

And really, have you even tried this yet?

Are you serious or just trolling?

You still haven't accepted Newtons laws. If you find a flaw in my previous post, please let me know what it is. It shows quite clearly that using enough force to bottom out (using constant force), the initial acceleration of a light cap IS more than 1G, ie more than gravity. More than twice as much, in fact (25.5m/s², or 2.6G). Even with a 2g cap, the initial acceleration is more than 9.81m/s² (13.24m/s²).

About the 59g, 1g thing, it WILL go down, but it won't go QUICKLY.

It's just as Linkbane says, the impulse required is larger for a heavier cap and grows parabolically for an increase in desired "quickness". You are not factoring this in at all, since you are doing static calculations only.

It will go down...at the speed of gravity...granted a spring slopes but that makes this way too hard so if it helps you visual, add more than 1g..use 2g...in fact, we can use 60g spring. Set one is 59g keycap.  Set two is 50g keycap.  You drop a 5g weight from .00001mm height on the 59g keycap.  It falls quickly.  You drop a 5g weight from .00001mm height on the 50g keycap..it doesn't fully depress.  Drop a 8g weight from .00001mm weight..it doesn't fully depress...

I'm assuming people aren't pressing down faster than the force of gravity whereas you are since the force of gravity would make it move 4mm in .028s.  Which is pressing down 35 times in 1 second.  You're using .02s which is pressing a key 50 times in 1 second.  Granted, this isn't the same as typing because you're lifting your fingers, etc...but it does put it in perspective how fast you need to press in order to be faster than gravity. 

I fully acknowledge if you want to move it faster than the force of gravity mass will play a part and it will take more force...

Seriously..have you tried stacking some coins?  How does it feel to you..press quickly with the coins and without...What seems to be faster to you?  Press down as quickly as you can...

[Oobly]

No.... it... won't... The acceleration it experiences will be based on the forces applied and final resulting force on the object being accelerated (the keycap and stem). Gravity is simply one of the forces.

Please stop with the coins thing, it's irrelevant to the discussion (being based on static calculations and ignoring dynamics). I will not be replying further in this thread as I feel I have said all that needs saying.

[Polymer]

I'm curious if you aren't testing it (which takes all of 10 seconds) because you're afraid of the results..or because you already know you'll be wrong as a result. 

Either way, it is a simple test for anyone here to try themselves...No need to take someone's word for it...or look at some calculations which are not solving for the correct problem...just try it yourself..make your own decision..

[Photoelectric]

I asked a while ago and no one replied... and I can't quite tell from the photos: are the thick PBT caps Cherry profile or OEM?  If Cherry, then there is your a answer.   It's not about weight here, it's about torque.  From experience, the difference in height makes for a noticeable difference in torque.  If it's OEM profile, then it doesn't make sense that the switches would feel heavier vs. other OEM caps.

[Saviant]

The thick PBT caps are Cherry Profile

[tbc]

i thought vortex made thick pbt oem profile with the really bad italized font?

[Linkbane]

The thick PBT caps are Cherry Profile

They are not, and you don't have any evidence. The Ducky caps are certainly OEM, which is obvious since they're a Chinese-based company.

[Polymer]

The thick PBT caps are Cherry Profile

They are not, and you don't have any evidence. The Ducky caps are certainly OEM, which is obvious since they're a Chinese-based company.

I think he's probably thinking of the IMSTO ones which are Cherry profile.  Ducky are OEM profile.  The new Vortex DS Thick PBT ones are OEM as well. 

[Oobly]

I asked a while ago and no one replied... and I can't quite tell from the photos: are the thick PBT caps Cherry profile or OEM?  If Cherry, then there is your a answer.   It's not about weight here, it's about torque.  From experience, the difference in height makes for a noticeable difference in torque.  If it's OEM profile, then it doesn't make sense that the switches would feel heavier vs. other OEM caps.

I believe the caps are the same profile (OEM), but I would love to hear an explanation of where you find rotational force (torque) in a linear system (vertical key movement) which changes based on keycap height. Not trying to be argumentative, just really want to know, since I don't see it myself.

[sprk]

Yeah regardless of all the disagreements and explanations, I fail to see what torque has to do with anything. Physics, math, and calculations aside I still believe this whole deal is a case of brand new vs older/used switches. Hell I just got a new board (same brand and model) with blues and they do feel a little bit harder than the board I now keep at work.

[Saviant]

The thick PBT caps are Cherry Profile

They are not, and you don't have any evidence. The Ducky caps are certainly OEM, which is obvious since they're a Chinese-based company.

Well the first lot of thick pbt I saw sold where from Imsto and were cherry profile, the ducky ones only came on certain boards so you couldn't buy them separate and didn't know about the crappy looking font ones.

[Linkbane]

The thick PBT caps are Cherry Profile

They are not, and you don't have any evidence. The Ducky caps are certainly OEM, which is obvious since they're a Chinese-based company.

Well the first lot of thick pbt I saw sold where from Imsto and were cherry profile, the ducky ones only came on certain boards so you couldn't buy them separate and didn't know about the crappy looking font ones.

So what you're saying is that you based your 'knowledge' of all thick PBT caps' profile on one set you saw from IMSTO and never bothered to check the much more common ones on Ducky's keyboards or Vortex?

[Saviant]

So where is your proof that the oem profile are the most common?
Do you have numbers to show which sold more?

I have 3 different sets of the Imsto sets, as well as custom made ones. All in cherry profile.

[Photoelectric]

Yeah regardless of all the disagreements and explanations, I fail to see what torque has to do with anything. Physics, math, and calculations aside I still believe this whole deal is a case of brand new vs older/used switches. Hell I just got a new board (same brand and model) with blues and they do feel a little bit harder than the board I now keep at work.

It would have an effect if the thick PBT caps in question were Cherry profile.  1. because Physics, and 2. personal experience where I can feel the difference.

In this case though, if the caps are the same OEM profile, it's probably minor differences between the two keyboards, and as you said, worn in used switches vs. new.

[Oobly]

Yeah regardless of all the disagreements and explanations, I fail to see what torque has to do with anything. Physics, math, and calculations aside I still believe this whole deal is a case of brand new vs older/used switches. Hell I just got a new board (same brand and model) with blues and they do feel a little bit harder than the board I now keep at work.

It would have an effect if the thick PBT caps in question were Cherry profile.  1. because Physics, and 2. personal experience where I can feel the difference.

In this case though, if the caps are the same OEM profile, it's probably minor differences between the two keyboards, and as you said, worn in used switches vs. new.

But how do you get any torque in a linear movement? A diagram would be great.

[Photoelectric]

I linked a wikipedia article to torque.  The lever is your hand, pivoted about where you rest it (on your thumb near a spacebar or wherever you like to hold it, your palm base, etc).  It's not actually linear downward motion, although in very small travel distance approximation it could be viewed as such.

P.S.: that's for regular hand positioning and touch typing.  If you're standing over your keyboard and punching on the keycaps with your finger pointed down in a direct downward motion--that would be an example of linear motion for typing.

[Oobly]

I linked a wikipedia article to torque.  The lever is your hand, pivoted about where you rest it (on your thumb near a spacebar or wherever you like to hold it, your palm base, etc).  It's not actually linear downward motion, although in very small travel distance approximation it could be viewed as such.

P.S.: that's for regular hand positioning and touch typing.  If you're standing over your keyboard and punching on the keycaps with your finger pointed down in a direct downward motion--that would be an example of linear motion for typing.

But if you float your hands while typing (as you should) the "pivot" is the first knuckle of your finger and the position will be almost exactly the same relative to the top of the cap as with any other cap. The only perceivable difference will be the same as adjusting the height of your chair or desk by a couple mm. Not really significant, is it?

Cherry profile does feel different, but it has nothing to do with torque. More to do with relative keycap positions (reach) and surface angles.

I agree, the difference in feel is probably mostly just new springs vs old, but heavier caps do feel different on the same springs, mostly due to the increase in impulse needed at higher speeds.

[Photoelectric]

Torque is a physical property.  Physics is everywhere in everything you physically do, so yes, it still has to do with torque.  Even if you don't move your hands at all (which you do when floating during touch typing: watch your hands while typing, you'll see).  Your fingers  and even your whole hand are a chain of interconnected pivots.  Cap profile, which includes height and surface angle, and the angle at which you apply force, all matter.   You'd have to draw hundreds of force diagrams for each scenario, but nonetheless, torque is more significant here than keycap weight, the difference in which is negligible in this case versus the force required to actuate (and bottom out).  Your second paragraph does in fact imply that the geometry changes with each profile, thus your force diagrams will be slightly different from one profile to another.  It doesn't change the physics concept behind it though.

[tp4tissue]

I linked a wikipedia article to torque.  The lever is your hand, pivoted about where you rest it (on your thumb near a spacebar or wherever you like to hold it, your palm base, etc).  It's not actually linear downward motion, although in very small travel distance approximation it could be viewed as such.

P.S.: that's for regular hand positioning and touch typing.  If you're standing over your keyboard and punching on the keycaps with your finger pointed down in a direct downward motion--that would be an example of linear motion for typing.

But if you float your hands while typing (as you should) the "pivot" is the first knuckle of your finger and the position will be almost exactly the same relative to the top of the cap as with any other cap. The only perceivable difference will be the same as adjusting the height of your chair or desk by a couple mm. Not really significant, is it?

Cherry profile does feel different, but it has nothing to do with torque. More to do with relative keycap positions (reach) and surface angles.

I agree, the difference in feel is probably mostly just new springs vs old, but heavier caps do feel different on the same springs, mostly due to the increase in impulse needed at higher speeds.

It's torque like PHOTO said..   That's one of the advantages of Topre, because it can distribute the grinding more evenly against the inner shaft..

The design of the keycap shape is made to convert as much of the force straight down as possible, but the stem hitting the wall is unavoidable, and that IS torque due to the pivot and lever.

[laffindude]

so much fud in this thread...

[tp4tissue]

so much fud in this thread...

yup

it border lines make believe..   incomplete applications, to completely wrong assumptions... LOLOL..

a few days back I thought, maybe I'll fix it..  but it is actually so far gone that there isn't much to say besides some mean words...

[Oobly]

so much fud in this thread...

^^ agreed. I recommend OP closes it. It makes me tired trying to figure out the best way to explain things.

Summary from my side:

Profile is irrelevant to the thread since OP is comparing same profile keys with different mass (why they feel different to each other is another discussion). OP himself understands the impact on increase in required force to type at the same high speed (larger impulse), as shown in my last post with calculations included. Nothing constructive further to add to the discussion. Over and out.

[Polymer]

Too bad your calculation is wrong.   It only works when you exceed the speed of gravity but that doesn't seem likely for most people.  You won't even do the coin thing cause you know you're afraid of being wrong...it isn't a static calculation...just try it..inviting anyone to try it...put a few more grams of weight on a big key...easier to press down quickly?  Sure seems like it...try to press down FAST...seems easier to me.  If I was able to accelerate the key so I could could cover the travel in less than .028 seconds than the heavier key would require more force but since that isn't the case, you're wrong.  You're even admitting 1key press per second would require less force..but then you use .02s as your starting point.  .02s is 50 presses in ONE SECOND.  That isn't how fast you're pressing a key.  .028s is 35 in ONE SECOND.  I doubt people are hitting that speed. 

Easy way to show me...do all the math..there is a curve going from 5s to .01 seconds..at some point the heavier key will require more force..and there is a point where it doesn't....If your math ends up being even at 5s for a key press it requires more force you know your math is wrong..we can prove that...

 

[Linkbane]

This has gone too far, thread nuked. Thank you for the responses.