What is the Difference between IBM Model M and Model F Key-Switches?

[aref]

I've had many Model M KBs; but I see where many on GH say Model F key switches feel different, perhaps far better than Model Ms. If you can tell me, what is the difference in feel between a Model M and Model F key switches? I thought I had moved away from IBM KBs, but this Model F preference on GH has captured my curiosity. Thanks, GH.

[Ludovician]

Model Ms are buckling spring over membrane, whereas Model Fs are capacitive BS. I couldn't tell you the difference in feel from experience, because I don't have my Model F yet. The capacitive BS boards also support full NKRO.

[CPTBadAss]

In addition to Ludovician's info, Fs have a metal case. And to me the switches feel a touch lighter in terms of actuation  force. And the metal plates make the typing experience a little more lively and bouncy. The M feels a little dull and muted in contrast. Easiest way to compare the two is probably to try them side by side at a meetup. I did the comparison at the first Chicago keycon. I'm not adamant that I'd go with only Model F but there's definitely a difference in the typing feel to me.

[chyros]

The sound is also quite different, a lot more pingy in the Model F. I don't have an F yet, so I couldn't say anything about the feeling yet, though.

[aref]

Ludovician and CaptBadAss: Thanks guys. I had about six or seven Model Ms that I ended up selling. I listened to some Model Fs on youtube to hear the difference. But so many have been modified, that there's little aural consistency. I may have to do more research. I see where a GH member, joestran1, has a couple for sale on ebay. Looks like he's put in some time restoring the keyboards.

More pingy--ouch! The ping from many KBs I've owned, IBM/Filco/CMQFR, have been a bit much for me. The good thing about my 87U is zero ping and 55g switches. Testing one would be best. However, in place of testing, I'll look at more youtube overviews.

[fohat.digs]

Don't let people's obsession with "sound" put you off. The painful overtones of the metallic ping can be successfully attenuated with a floss mod and some padding (which I do to ALL of my Model Fs).

The difference in feel is significant and I attribute it to multiple rigid plates bent into a curved shape and in constant tension and compression relative to each other.

My daily driver has been a Model F for 2-3 years now, and there is nothing like it.

Day before yesterday, I did a complete clean and bolt-mod on a 1987 Model M SSK, which is arguably just about the top shelf specimen (and the second that I have done in the past half-year or so) and there is still no comparison. The Model M keys are heavier and the sound is a dull thunk as opposed to what some people have described as the Model F's "singing"

And, by the way, I will continue to argue that IBM M/Fs do not have "switches" in the conventional sense, and that the buckling spring assemblies are merely mechanisms which activate switches.

[CPTBadAss]

I like the machine gun funk of an F. Nice and loud. Very pingy.

Only thing that would make it better is when I hook up the beeper.

[Nai_Calus]

The physical difference in what you're pushing on the F compared to the M is a slightly lighter spring and a bigger hammer, contacting a capacitive PCB instead of a membrane.

The overall experience is lighter and akin to typing on bubble wrap, the small kind that pops easily.

I see where people get ping from the sound, but honestly it's not the same as MX board ping. My Monoprice pings and it's irritating. The F absolutely has those high metallic overtones but it's not an unpleasant, inconsistent thing, it's just part of the sound and every key makes it consistently.

[aref]

The physical difference in what you're pushing on the F compared to the M is a slightly lighter spring and a bigger hammer, contacting a capacitive PCB instead of a membrane.

The overall experience is lighter and akin to typing on bubble wrap, the small kind that pops easily.

I see where people get ping from the sound, but honestly it's not the same as MX board ping. My Monoprice pings and it's irritating. The F absolutely has those high metallic overtones but it's not an unpleasant, inconsistent thing, it's just part of the sound and every key makes it consistently.

Thank you for such a succinct and deft explanation on the difference between Models M and F BSs. The distinction you made between the annoying MX KB ping and that of a Model F 'resonates' with me.

[fohat.digs]

Thank you for such a succinct and deft explanation on the difference between Models M and F BSs.

The distinction you made between the annoying MX KB ping and that of a Model F 'resonates' with me.

If you take them apart you instantly see that under the surface a Model M and a Model F have very little in common.

And yes, MX ping is the worst and most annoying, even if the actual decibels aren't that many.

[0100010]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens) and different sound when it buckles against the barrel (along with the rest of the generally metal assembly).

Model M spring is thicker / shorter which results in a higher actuation force, and the generally plastic assembly resonates differently.

Referring to a Model M as dull, and a Model F as alive seems pretty accurate to me.  Feeling wise, I definitely prefer Model F to M.

[Touch_It]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens) and different sound when it buckles against the barrel (along with the rest of the generally metal assembly).

Model M spring is thicker / shorter which results in a higher actuation force, and the generally plastic assembly resonates differently.

Referring to a Model M as dull, and a Model F as alive seems pretty accurate to me.  Feeling wise, I definitely prefer Model F to M.

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Sums it up quite nice.  I have noticed though that my Unicomp M sounds higher pitched and more pingy than my terminal M FWIW, though its still definitely an M and F is in a whole other class.

[aref]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens) and different sound when it buckles against the barrel (along with the rest of the generally metal assembly).

Model M spring is thicker / shorter which results in a higher actuation force, and the generally plastic assembly resonates differently.

Referring to a Model M as dull, and a Model F as alive seems pretty accurate to me.  Feeling wise, I definitely prefer Model F to M.

Show Image

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Thanks for the visual and comment. I had no idea there was such a marked difference between Model M and F switch components. Thank you.

[chyros]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens)

From what I've seen of force curves and documentation, this doesn't appear to be true. MX Green actuates at 80 cN - noticeably higher than capacitive (60-65 gf) OR membrane (65-70 gf) buckling springs. Also, I only have Greens in a tester, but it definitely felt stiffer than any of my Model Ms.

[0100010]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens)

From what I've seen of force curves and documentation, this doesn't appear to be true. MX Green actuates at 80 cN - noticeably higher than capacitive (60-65 gf) OR membrane (65-70 gf) buckling springs. Also, I only have Greens in a tester, but it definitely felt stiffer than any of my Model Ms.

When I take an MX Green switch, invert it and press the stem down on any key on a buckling spring board, it always the MX Green switch that actuates first, then the buckling spring.  If I continue pressing until they both bottom out, then slowly release pressure - it is always  the buckling spring that resets first, followed by the MX Green.  I do agree that MX Greens feel heavier though.

[jacobolus]

MX Green actuates at 80 cN

I don’t think this is correct, at least based on experience I’ve had typing on people’s MX green keyboards at meetups. Maybe you’re talking about the force to fully depress the switch?

[Melvang]

Don't let people's obsession with "sound" put you off. The painful overtones of the metallic ping can be successfully attenuated with a floss mod and some padding (which I do to ALL of my Model Fs).

The difference in feel is significant and I attribute it to multiple rigid plates bent into a curved shape and in constant tension and compression relative to each other.

My daily driver has been a Model F for 2-3 years now, and there is nothing like it.

Day before yesterday, I did a complete clean and bolt-mod on a 1987 Model M SSK, which is arguably just about the top shelf specimen (and the second that I have done in the past half-year or so) and there is still no comparison. The Model M keys are heavier and the sound is a dull thunk as opposed to what some people have described as the Model F's "singing"

And, by the way, I will continue to argue that IBM M/Fs do not have "switches" in the conventional sense, and that the buckling spring assemblies are merely mechanisms which activate switches.

I just want to concur with fohats statement.  Don't give in to other peoples obsessions.  I don't obsess over the sound of my F's, I just don't care for the continuing ring of them.  I do a floss mod, replace the mat, and use rattle can plastidip on the plates.  I have a clip where I do a short typing test for sound, do the floss mod, then another typing test to show the difference between before and after.  Granted I don't actually use floss, but what I use works great.

[Huxley2500]

I like the machine gun funk of an F. Nice and loud. Very pingy.

Only thing that would make it better is when I hook up the beeper.

Sounds like my kind of Clicky switch!

[Nai_Calus]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens)

From what I've seen of force curves and documentation, this doesn't appear to be true. MX Green actuates at 80 cN - noticeably higher than capacitive (60-65 gf) OR membrane (65-70 gf) buckling springs. Also, I only have Greens in a tester, but it definitely felt stiffer than any of my Model Ms.

When I take an MX Green switch, invert it and press the stem down on any key on a buckling spring board, it always the MX Green switch that actuates first, then the buckling spring.  If I continue pressing until they both bottom out, then slowly release pressure - it is always  the buckling spring that resets first, followed by the MX Green.  I do agree that MX Greens feel heavier though.

Weird. I've had the exact opposite experience. Taking a keychain with an MX green and putting it upside down over a key on my Model F, the F spring buckles before the Green clicks, and the click on coming up occurs before the green releases. Are you doing it on an M maybe? Because this is just odd.

[chyros]

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens)

From what I've seen of force curves and documentation, this doesn't appear to be true. MX Green actuates at 80 cN - noticeably higher than capacitive (60-65 gf) OR membrane (65-70 gf) buckling springs. Also, I only have Greens in a tester, but it definitely felt stiffer than any of my Model Ms.

When I take an MX Green switch, invert it and press the stem down on any key on a buckling spring board, it always the MX Green switch that actuates first, then the buckling spring.  If I continue pressing until they both bottom out, then slowly release pressure - it is always  the buckling spring that resets first, followed by the MX Green.  I do agree that MX Greens feel heavier though.

Weird. I've had the exact opposite experience. Taking a keychain with an MX green and putting it upside down over a key on my Model F, the F spring buckles before the Green clicks, and the click on coming up occurs before the green releases. Are you doing it on an M maybe? Because this is just odd.

I've found this method to be extremely unreliable. I've managed to get completely contradictory and misleading results doing this. Using BS, it's even worse, because you can really only do this with a key cap still on the springs which ****s up the results even more as the force acting on the buckling spring will deviate by cos θ in two dimensions (with θ the angle of the profile of the key cap laterally and longitudinally). Even in an unskewed head-on I managed to get it to fail, though. Leave measuring forces to machines or dedicated setups.

MX Green actuates at 80 cN

I don�t think this is correct, at least based on experience I�ve had typing on people�s MX green keyboards at meetups. Maybe you�re talking about the force to fully depress the switch?

Nah, that's usually around or over 100 isn't it? It's 80 cN according to the DT wiki: http://deskthority.net/wiki/Cherry_MX_Green and 80 gf according to mechanicalkeyboards.com: http://mechanicalkeyboards.com/shop/index.php?l=product_list&c=48

[SamirD]

In our typing class back in high school we had IBM XTs with 360k floppies and Model Fs (I'm dating myself a bit, but whatever). 

The sound is also quite different, a lot more pingy in the Model F. I don't have an F yet, so I couldn't say anything about the feeling yet, though.

This is a very accurate description.  They have a more 'metallic' sound.

In addition to Ludovician's info, Fs have a metal case. And to me the switches feel a touch lighter in terms of actuation  force. And the metal plates make the typing experience a little more lively and bouncy. The M feels a little dull and muted in contrast. Easiest way to compare the two is probably to try them side by side at a meetup. I did the comparison at the first Chicago keycon. I'm not adamant that I'd go with only Model F but there's definitely a difference in the typing feel to me.

This is exactly what I recall from my days of typing on an F.  We had an M at home, so I could actually tell the difference and this describes it to a t (we still have that M, and the PS/2 30-286 that it came with).

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens) and different sound when it buckles against the barrel (along with the rest of the generally metal assembly).

Model M spring is thicker / shorter which results in a higher actuation force, and the generally plastic assembly resonates differently.

Referring to a Model M as dull, and a Model F as alive seems pretty accurate to me.  Feeling wise, I definitely prefer Model F to M.

Show Image

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Thanks for the visual and comment. I had no idea there was such a marked difference between Model M and F switch components. Thank you.

Thank you again for the visuals.  It really brings the differences to life.

[SamirD]

In our typing class back in high school we had IBM XTs with 360k floppies and Model Fs (I'm dating myself a bit, but whatever). 

The sound is also quite different, a lot more pingy in the Model F. I don't have an F yet, so I couldn't say anything about the feeling yet, though.

This is a very accurate description.  They have a more 'metallic' sound.

In addition to Ludovician's info, Fs have a metal case. And to me the switches feel a touch lighter in terms of actuation  force. And the metal plates make the typing experience a little more lively and bouncy. The M feels a little dull and muted in contrast. Easiest way to compare the two is probably to try them side by side at a meetup. I did the comparison at the first Chicago keycon. I'm not adamant that I'd go with only Model F but there's definitely a difference in the typing feel to me.

This is exactly what I recall from my days of typing on an F.  We had an M at home, so I could actually tell the difference and this describes it to a t (we still have that M, and the PS/2 30-286 that it came with).

Model F spring is thinner / taller which results in a lower actuation force (slightly - it is still higher than MX Greens) and different sound when it buckles against the barrel (along with the rest of the generally metal assembly).

Model M spring is thicker / shorter which results in a higher actuation force, and the generally plastic assembly resonates differently.

Referring to a Model M as dull, and a Model F as alive seems pretty accurate to me.  Feeling wise, I definitely prefer Model F to M.

Show Image

Show Image

Thanks for the visual and comment. I had no idea there was such a marked difference between Model M and F switch components. Thank you.

Thank you again for the visuals.  It really brings the differences to life.

[SamirD]

Sorry about the dupe post--got a weird error message about something not being an integer?

[aref]

I just want to concur with fohats statement.  Don't give in to other peoples obsessions.  I don't obsess over the sound of my F's, I just don't care for the continuing ring of them.  I do a floss mod, replace the mat, and use rattle can plastidip on the plates.  I have a clip where I do a short typing test for sound, do the floss mod, then another typing test to show the difference between before and after.  Granted I don't actually use floss, but what I use works great.

Thanks for linking your youtube clip. The paracord strands inserted into the springs, along with your other mods, makes for solid sounding Model F. Nicely done.

[Melvang]

Sorry about the dupe post--got a weird error message about something not being an integer?

That comes from quoting the user 0100010