What Are Your IBM Model F Preferences? (XT vs AT vs 122...)

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Chyros

04 Jul 2019, 15:53

Fkazim wrote:
04 Jul 2019, 14:11
Wazrach wrote:
04 Jul 2019, 13:25
Fkazim wrote:
04 Jul 2019, 00:50


I think the AT is a little lighter but to be honest the plastic on the AT is far superior to the plastic used on the XT heres why.

1) The AT plastic is the same plastic used on the Model M (PVC) as this is the case the plastic is much more flexible meaning the AT is much less likely to get cracked and almost impossible to get faded over time.

2) The AT uses PVC plastic that is not painted meaning there is no chance of any paint flaking off or wearing off like it can on XT as that uses painted plastic which dirt really sinks into.

3) This one everyone may not agree with but the Plastic on the AT in my experience is easier to clean than the painted plastic on the Model F XT.

The only disadvantage to the AT's construction is that the bottom case is not made of metal and instead uses plastic with locking tabs along the bottom and screws along the top. Anyways that's just my findings and opinion.
I disagree. I've had about 9 XTs and two ATs. The XT's plastic is much thicker and feels a lot tougher. It sounds dense when knocking on it. The AT and F122 seem to use the same kind of plastic, which is a lot thinner and more susceptible to cracks. I think they used slightly different types of plastic, as one AT shower streaking after cleaning with isopropanol, whereas the other one didn't. Of course, the cases are still prone to scratches and wear - simply scrubbing the case with a scourer was enough to wear away the paint.

It's very obvious that IBM were pinching pennies with the AT Model F, compared to the XT. The F122 is of course much heavier, but the case is still thin and brittle.
The AT uses the same plastic as the Model M it is thinner but not brittle, very flexible and less likely to crack. Where as the XT uses a thicker denser but more brittle plastic which is more likely to crack. Also it is painted meaning once the paint flakes off or wears off you are left with a yellow coloured plastic underneath.

My AT is made from the exact same plastic as my Model M's 1st gen's and 2nd gen's plastic for sure. Also the plastic on my F122 is the same painted plastic as on my XT

So this is how all the keyboards are in my experience

IBM Model M- Thin flexible PVC Plastic

IBM Model F AT- Thin Flexible PVC Plastic

IBM Model F XT- Thick Dense Painted Brittle Plastic

IBM Model F122- Thick Dense Painted Brittle Plastic

Attached below is an example how the Thick dense painted brittle plastic can crack. The keyboard in the picture 1 is an F122 and the keyboard in picture 2 is an XT. The whole seperation between the F keys and the Alpha numeric keys
How do you know your AT is made out of PVC?

Fkazim

04 Jul 2019, 16:11

Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?

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AJM

04 Jul 2019, 16:32

Wazrach is of course correct. The other cases can't hold a candle to an XT.
And should anybody hit the case with an axe, you can touch the XT up with a bit of paint, while on the other "pure" plastik cases it will never look right again.

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Chyros

04 Jul 2019, 16:37

Fkazim wrote:
04 Jul 2019, 16:11
Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.

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Wazrach

04 Jul 2019, 16:53

Chyros wrote:
04 Jul 2019, 16:37
Fkazim wrote:
04 Jul 2019, 16:11
Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.
Your AT sounds fantastic. It's unusually deep and thocky.

Fkazim

04 Jul 2019, 17:03

Chyros wrote:
04 Jul 2019, 16:37
Fkazim wrote:
04 Jul 2019, 16:11
Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.
Yeah that's true anyways I will take some pictures of my AT's plastic tonight and my XT also. Might help us determine the plastics easier. If you could do the same Chyros we could compare as yours was made in 1986 if i remember correctly from your review on it and mine was made in 1984 so we will really be able to see the variation between the two if there were any changes made over the years. Both mine and your AT were made in the United Kingdom so it would be a completely fair test.

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Wazrach

04 Jul 2019, 17:42

Fkazim wrote:
04 Jul 2019, 17:03
Chyros wrote:
04 Jul 2019, 16:37
Fkazim wrote:
04 Jul 2019, 16:11
Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.
Yeah that's true anyways I will take some pictures of my AT's plastic tonight and my XT also. Might help us determine the plastics easier. If you could do the same Chyros we could compare as yours was made in 1986 if i remember correctly from your review on it and mine was made in 1984 so we will really be able to see the variation between the two if there were any changes made over the years. Both mine and your AT were made in the United Kingdom so it would be a completely fair test.
I'm so sad, but... I know that his AT was made in 1989. :I

Fkazim

04 Jul 2019, 18:41

My mistake sorry

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SneakyRobb

04 Jul 2019, 19:08

It may not impact it as much as the case does, but one thing to remember is that the FXT, FAT and F122 came with different and varying capacitive feet as well as arguably slight differences in the springs/angles of springs.

As seen here.

viewtopic.php?t=9715

I actually used XT feet, and caps on my F122 and in my opinion it is slightly better feeling. I am not sure why they were ever different at all.

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Wazrach

04 Jul 2019, 19:27

SneakyRobb wrote:
04 Jul 2019, 19:08
It may not impact it as much as the case does, but one thing to remember is that the FXT, FAT and F122 came with different and varying capacitive feet as well as arguably slight differences in the springs/angles of springs.

As seen here.

viewtopic.php?t=9715

I actually used XT feet, and caps on my F122 and in my opinion it is slightly better feeling. I am not sure why they were ever different at all.
The F122 I opened had flippers I had never seen before up until that point - the ones with the rounded corners. Most XTs in the UK seemed to use the square-type flippers, with one of them having a single flipper with angled corners for the spacebar.

Since every Model F feels and sounds different, it's hard to talk about one specific model when it comes to feel and sound. I've had about 9 XTs now, all of them feeling and sounding completely different. The ATs tend to be pingier for some reason, with the first one I owned being quite twangy and the second one having a higher-pitched ping and louder thock. I did not open them to see the flippers.

This XT I am currently typing on (without a case) is quite different to the other XTs. It sounds very high-pitched, clicky and crisp, but also very pingy. I bought the assembly from Redmaus after asking him to find the pingiest one he had in his inventory. It barely has any dirt on it, but has quite a bit of corrosion on the barrel frame, as well as rust on the backplate. The foam has disintegrated, but the key feel hasn't been impacted, strangely. Other XTs with weak foam tend to feel bad after simply removing the keycaps for cleaning. It also has a shiny green backplate and no "shop date" sticker.

It never ceases to amaze me how many slight variations there are between Model F keyboards. How come every single one has a different pitch (ping and thock)? How come some are thockier than others, or clickier?

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Chyros

04 Jul 2019, 21:41

Well, I had a look, and yes, the plastic seems more flexible than I remembered it to be. It's also not yellowed in the slightest. The texture is also injection-moulded, not painted. And, as Jordan noted, it's from 1989, well into the era where they made the PVC Model M.
Of course, none of this is proof that it's PVC, but it's definitely a possibility :) .
Wazrach wrote:
04 Jul 2019, 16:53
Chyros wrote:
04 Jul 2019, 16:37
Fkazim wrote:
04 Jul 2019, 16:11
Well main reason is because the Model M is made of flexible PVC and when I compare the plastic of my AT they both feel and look exactly the same as the plastic on the Model M and also my AT is definitely not painted to give it its texture. I can take some pictures of the plastic on my At later tonight if you would like?
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.
Your AT sounds fantastic. It's unusually deep and thocky.
Is it? xD I mean it's definitely my nicest-sounding Model F, but does it really sound that different from other F ATs? =o

User avatar
Wazrach

04 Jul 2019, 22:21

Chyros wrote:
04 Jul 2019, 21:41
Well, I had a look, and yes, the plastic seems more flexible than I remembered it to be. It's also not yellowed in the slightest. The texture is also injection-moulded, not painted. And, as Jordan noted, it's from 1989, well into the era where they made the PVC Model M.
Of course, none of this is proof that it's PVC, but it's definitely a possibility :) .
Wazrach wrote:
04 Jul 2019, 16:53
Chyros wrote:
04 Jul 2019, 16:37
Thing is, plastics is a very complicated topic, and it's often quite hard to determine what a certain plastic is. It's hard enough to determine even with keycaps, where there are only three or so polymers in common use. Cases is a whole different kettle of fish ;) . For example, there are Model M cases that yellow, despite how PVC supposedly doesn't yellow, for example.

I'll have a look at my own AT today as well.
Your AT sounds fantastic. It's unusually deep and thocky.
Is it? xD I mean it's definitely my nicest-sounding Model F, but does it really sound that different from other F ATs? =o
I think it's mainly the spacebar that completes it. Keyboard acoustics are weird. My desk is quite hollow, so I've got three extended mousepads stacked on top of each other to help reduce vibrations. The ATs sounded quite muted and disappointing on my desk, but good on a hard table. The XT sounds great on both, but doesn't have the thock of the AT. I would prop the feet up of my AT to make sure the thock could run rampant. :P

Fkazim

04 Jul 2019, 22:52

Here's a comparison of all the different models plastic types hope that helps. As you can probably tell the Model M's and the AT's plastic look pretty much identical both in colour and texture. The XT Texture is much more subtle and more of a cream colour than the white colour like the Model M and the AT. Let me know your thoughts of course other Model F AT's could be made of a different types of plastic but the keyboards I am going by manufacture dates are as follows

IBM Model F X: 1984

IBM Model F AT: 1984

IBM Model M 1st gen square metal badge: 1987

All of the keyboards in the image were made in Greenock scotland United Kingdom.
Attachments
IMG_20190704_215003.jpg
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Last edited by Fkazim on 05 Jul 2019, 10:16, edited 1 time in total.

sh1

05 Jul 2019, 08:17

Not sure of the year of manufacture, but I'm afraid my AT was still of the painted variety. (I had lightly sanded the original paint, before painting mine black.)

And kind of scary when opening the plastic case...figuring it has the earlier more brittle plastic. (Though I don't know.)

Fkazim

05 Jul 2019, 08:59

sh1 wrote:
05 Jul 2019, 08:17
Not sure of the year of manufacture, but I'm afraid my AT was still of the painted variety. (I had lightly sanded the original paint, before painting mine black.)

And kind of scary when opening the plastic case...figuring it has the earlier more brittle plastic. (Though I don't know.)
That's very interesting your AT might be older than mine. Is your AT American made it could be the UK used non painted plastic and the US used the same painted plastic as on the XT. Do you have a picture of the painted case before you repainted it if so it would be interesting to see that.

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