Hi,

From what I read here and there, the T4x have an enclosure done of titanium alloy.
And the screen cover would be a magnesium alloy.

For the X40 and X41, the enclosure seems regular plastic, but the base looks reinforced
(maybe titanium alloy ?) as well as the screen cover (magnesium ?)

I also read that some models are reinforced from carbon fibers and that some have a composite base (plastic-metal sandwich).

I know there are many discussions about Thinkpads reinforcements, but I hardly can find a list of which past and current series use Titanium, which ones use carbon fiber, a.s.o.

Very often in the Thinkpad reviews, it is mentioned that the enclosure is done of reinforced plastic, without specifying the nature of the reinforcement. Especially, I can hardly find in which series is carbon fiber.

Would it be possible to list which reinforcements applies to which series?
Are there differences by sub-series or even by type?

For a while I thought the Thinkpad 600 had titanium on it but I disassembled a few and it was made mostly of plastic, probably glass fiber reinforced and very strong. So I never found titanium. Magnesium has a higher weight to strength ratio and is cheaper so it's very unlikely that you'll see something else.

Carbon fiber is a different reinforcement for plastics and it costs quite a bit. The only model I'm sure contains it is the expensive X300/X301. Still, the X300/X301 contains a frame made of magnesium. Maybe the new X1 Carbon but not much else that I'm aware of.

Generally speaking, all thinkpads are made of plastics with different reinforcements. Some contain magnesium frames. Hinges and other metallic internal parts are made of stainless steel.

By the way, if you wonder why some models are sturdier than others, it's not really the material they are made of but the design of the chassis. Look for "thinkpad 600 base" on google images and you'll see that the way the frame was designed, it had several crossbeams running along the chassis, linking top with bottom and reducing leverage. Newer models are essentially boxes without crossbeams and thus flex quite a bit more.

They flex more *externally*. The addition of the magnesium frame has cut down on planar flex quite a bit -- and as a result, the case doesn't need to be as stiff anymore.



The X4x used a magnesium top and bottom chassis with a plastic palmrest and screen bezel (ABS, I think).



In general, the information is in the PSREF. I've found that reviews are frequently incorrect when it comes to the materials used.

No to Titanium alloy, yes to magnesium AFAIR. T4x series were pretty but far from tough and/or seriously reinforced in any respect.



The only Titanium part of any ThinkPad were lid covers on certain Z-series models.



Most of the reviewers have never taken a ThinkPad apart...

What exactly are you trying to determine? What's the toughest ThinkPad ever built?

Thank you for all your answers.

What I'm trying to determine is what is myth and what is reality.

On Wikipedia, a lot is written about special materials that are used to build Thinkpad enclosures, but I could never corroborate some of those informations. Then, I was wondering about which Thinkpad models the people who wrote on Wikipedia are speaking.

It is also curiosity. I like knowing that some material with titanium is like this and some other with carbon fiber is like this, a.s.o.

Concerning titanium, I don't think it is pure titanium (maybe too expensive) but an alloy.
In general, when you combine materials in an alloy or composite, the new material inherits more or less the characteristics of its components.

When you slightly knock the bottom of a T42, it doesn't sound exactly like common plastic, but like something hybrid between plastic and metal. Hard to know what it is exactly.
The X40 / X41 enclosure looks more common plastic, but the very bottom plate also seems like thus of the T4x series.

The R series are pure plastic but for some models the enclosure was very well designed (e.g. R31).

The T4x have very lightweight metallic profiles inside the enclosure. Some alloy maybe.

thinktwice wrote:



Good luck with that one.



Wikipedia is full of garbage. I was indifferent to it until I had to go in and correct nonsense written about my ancestors.



A degree in chemistry and related sciences might be an idea worth pursuing...you're not going to find much about that type of stuff by playing with ThinkPads...



That goes without saying.



Define "common plastic"...



I believe that most of us on this board would beg to differ with that...



Re-read ThinkRob's response to your original question....

Well, in documents available on IBM's and Lenovo's websites, I found what follows :

- T41, T42 and T43 lids contains titanium
- Carbon fiber is also mentioned for the T42
- Magnesium is mentionned for the T43

I could not find such informations for the T40.

At the time of the T23, the T-Series had both the bottom and the top cover lids in titanium composite.
(source: ftp://www6.software.ibm.com/software/se ... ies-TP.pdf)

Here are the detailed informations for the T41 to T43 :

T41
"The titanium composite cover gives you added strength."
source: http://www-01.ibm.com/common/ssi/rep_ca ... index.html

T42
"The ThinkPad T42 and T42p notebooks (...)
The advanced cover materials (including titanium composite CFRP (carbon fiber reinforced plastic) give added strength."
source: http://www-01.ibm.com/common/ssi/rep_ca ... ml#@2h@77@

T43
"The titanium and magnesium composite covers give added strength."
http://www-01.ibm.com/common/ssi/cgi-bi ... anguage=en

Some changes seem having occured with the firsts T60, T61.

T41 - Magnesium composite in the top cover, titanium-reinforced CFRP in bottom cover
T42 - Magnesium composite in the top cover, titanium-reinforced CFRP in bottom cover
T43 - Magnesium composite in the top cover, titanium-reinforced CFRP in bottom cover
T60 - 14.1": magnesium composite in top cover, CFRP bottom cover; 15": CFRP in top/bottom
T61 - Top: Super-Elastic PolyCarconate (SEPC); Bottom: Carbon-Fiber Reinforced Plastic
T400 - Top: Super-Elastic PolyCarbonate (SEPC); Bottom: Carbon-Fiber Reinforced Plastic
T400s - Display cover: Carbon-fiber reinforced plastic (top), glass-fiber reinforced plastic (side walls); Base: Magnesium alloy
T410 - Top: High Elasticity PolyCarbonate (HEPC); Bottom: Carbon-Fiber Reinforced Plastic
T410s - Display cover: Carbon-fiber reinforced plastic (top), glass-fiber reinforced plastic (side walls); Base: Magnesium alloy
T500 - Top: Super-Elastic PolyCarbonate (SEPC); Bottom: Carbon-Fiber Reinforced Plastic
T510 - Display cover: Glass-fiber reinforced plastic; Base: Carbon-fiber reinforced plastic
T420 - Display cover: Carbon-fiber / Glass-fiber hybrid; Bottom: Carbon-Fiber Reinforced Plastic
T420s - Display cover: Hybrid Carbon-fiber reinforced plastic; Bottom: Magnesium alloy
T520 - Display cover: Carbon-fiber / Glass-fiber hybrid; Bottom: Glass-fiber reinforced plastic without paint
X300 - Display cover: Carbon-fiber reinforced plastic (top), glass-fiber reinforced plastic (side walls); Base: Magnesium alloy
X301 - Display cover: Carbon-fiber reinforced plastic (top), glass-fiber reinforced plastic (side walls); Base: Magnesium alloy



*all info from different versions of Personal Systems Reference Lenovo® ThinkPad ® Notebooks

Yeah, I dissasembled a T41 today and it says CFRP in the bottom. Very nice stuff. You'll never find it on consumer grade notebooks.

Didn't do much to prevent planar flex, did it now?

While I don't work on consumer-grade notebooks, let's not lose perspective of how much "smoke & mirrors" ThinkPad image consisted of...

All the fancy terminology...all the charm of a pure-black-laptop...all the engineering oversights and and failures...

It wasn't supposed to prevent flexing to begin with because flexing has much more to do with geometry than it does with the material used. A good example of this is the casing from a Thinkpad 600 (GFRP) and a T4x (CFRP):

http://www.laptoppieces.com/os2000/images/DSC07017.JPG
http://i.pchub.com/i/IBM-Thinkpad-600-S ... -19629.jpg

The chassis material is thicker on the 600 but that isn't what made it stronger; it was its internal design. Modern notebooks have the battery on the back and hard and optical drives to the sides and this configuration makes it difficult to add internal ribbing. The Thinkpad 600 had everything in the front while the motherboard was mostly in the back and this allowed them to put separating ribs between components that were connected to each other making the design substantially stronger while remaining comparable in weight.

No, what fibers do is preventing plastic parts from "giving in", this is, composite materials don't change geometrically with stress; they just break. ABS plastic without reinforcements, as used in most consumer grade laptops, will usually give in in the first two years of use, making the chassis very sloppy. I don't really think the quality of the motherboard of a consumer grade laptop is lower compared to a Thinkpad's (they are probably made by the same factories anyway), what kills them is the lack of both proper design and resistant materials.

What made Thinkpas great was the commitment to put usability over design. The clamshell style of the lid, for example, looked ugly but increased the stiffness of the lid by an effect similar to an I beam. This design is gone from newer Thinkpads and most likely due to marketing reasons.

Could you please point me to examples of "usability over design" machines apart from the 600 series?

Personally, I believe that 600 series was a *great* design although I'm not a fan of it.

Durability of anything that came later on is debatable and I'm being very kind here...

The port selection on the X series?

Makes for chubby, "ugly" notebooks, but pretty bloody useful (at least for me.)

Actually, I'd go as far as to say that from the perspective of people who disassemble their ThinkPads, the usability has gotten a lot better over time (with the notable exception of the X1 series.) The X200 and X220 are absolute joys to disassemble compared to, say, the X40. Same for the T420 vs. the 600 series, etc.

(I'm not a fan of some of the recent aesthetics though... far too "slick" for my tastes. I like angular, busy designs. Needless to say, I feel quite ignored in the current market... )



<speculation>
AFAICT, the clamshell design is gone because we no longer have thick, easily-broken CCFL-backlit screens.

And because -- if my past ThinkPads are a representative sample -- it didn't really do all that much for lid strength. (I did like the look, but that's neither here nor there...)

Add those two to the fact that a lot of people seemed to think that it was part of what made ThinkPads look "old" or "outdated", and I can see why it'd get the axe.
</speculation>

Trackpoint? It's the default input on all Thinkpads despite being relatively unpopular otherwise. And my personal opinion is that most choice a touchpad not because it's better (it's improving though, with multitouch gestures and such) but simply because its way of operation is more obvious for the average (read=untrained) user. A trackpoint provides several advantages but from the naked eye its way of operation isn't obvious and this scares people.

Advantages of a trackpoint over a touchpad:

* Less stress on the hand. I don't recall the proper name but it's something like "infinite movement device", which means in plain terms that it travels any distance with a single command. On a touchpad you need to raise the finger several times to travel a long distance (and it's improving with intertial borders but still not to the point of a trackpoint). Also, you use the trackpoint with the hand resting on the palmrest and a touchpad is usually used with the hand in the air. And the classic argument that with a trackpoint you always keep your hands on the keyboard.

* Less footprint. A trackpoint requieres minimal space, usually resulting in no increase of size for its inclusion. On the contrary, a touchpad usually requieres to alter the design in some way and this is obvious in newer thinkpads with narrow horizontal screens. They make them bigger to accomodate a touchpad, period.

* More accuracy. This is subjective but most of the people who I've convinced to use the trackpoint instead of the touchpad reported that it's more accurate,

I guess I should've worded my question differently...

No argument from me on the trackpoint and its usability. Touchpad is disabled in BIOS on all of my ThinkPads that have one to begin with.

What I was referring to was the actual product line that would be a poster child for "usability over design" when it came to post-2000 ThinkPads...

X300? It's the last true Thinkpad. Thick bezels, though...

Yes, but the downside is that it's only usable by True Scotsman.

I won't laugh that much looking at where Thinkpads are heading to today...

A fabulous design, one of the prettiest ThinkPads ever.

That being said, atrocious screen and noisy fan have made the usability aspect rather problematic for many users.