Is key switch housing of Topre Realforce ABS?

[limmy]

I know that the keyboard housing of Realforce is made of ABS plastic. My question is whether the key switch housing, which holds slider(or plunger) that moves with key cap, is ABS.

The housing in question is the housing in this picture

(Image from Topre wiki http://geekhack.org/showwiki.php?title=Topre+Realforce+Reference+-+all+things+topre)

I am using HHKB, and for HHKB the keyboard housing acts as key switch housing as well. Also, I know the keyboard housing of HHKB is made of ABS.

I am asking this question because I feel increased friction between sliders and the plastic that holds the sliders on my HHKB and I wonder if the same problem would happen for Realforce keyboards. I have been using HHKB for 5 years now and the letter keys has become pretty heavy. It takes 13 nickels (65g) to activate heavily used letter keys and I wonder if it is partly due to housing worn out. Recently I got a like-new HHKB and the keys in the like-new board is significantly lighter and I also feel less friction.

Thanks!

[cactux]

are both boards pro 2?

[limmy]

Yes, I have two HHKB pro2s. One used for five years and one barely used(that is what seller told me).

are both boards pro 2?

[limmy]

I have disassembled two boards and shook the top housing like this guy would do (starting at 0:09)

http://www.youtube.com/watch?v=AWUNzAV-geA

The old HHKB kind of sticks(not all keys move freely). This could be partly due to the fact that I have tried to lube the plungers with silicone oil before, but it was worse before the lube. For example, if I tried to push the keys on the corners, it wouldn't go in. I know this because it felt a lot better after the silicone oil lube.

Also, the plungers show sign of wear. Worn out(not smooth) surfaces tend to have more friction.

I will try to clean off silicone oil see if that helps reducing friction. (but I have a feeling it wouldn't help..)

Also, I think ABS wearing out is main reason why membrane keyboards do not work as smoothly after some time of use. ABS is not usually used for parts that has to be wear resistant.

Quote from yahoo answer. ( http://answers.yahoo.com/question/index?qid=20070517152719AAVlRHv )

ABS not usually used for wear components so this data value is not usually measured.

I know it is not wise to quote random answers, but this guy seems to know this stuff.


EDIT: My feeling was wrong apparently. After washing off, the plungers pretty much move freely as seen on the video. However, I found that the friction part was not that important on actuation force measurement, although it affects feel of the keys.

i'd disassemble the board and see what kind of buildup is on the components.  i'm willing to bet they've gotten dirty and that's contributing the increased actuation force required.  worn out switches (in cherry's case anyhow) result in less actuation, but increased friction would require something more to be present inside the mechanism, not less (which would be the case in plastic wearing down).

[hasu]

Unfortunately 5 years might be long enough to wear HHKB, though I don't know whether Realforce wear or not.
My two pros had worn in 6-7 years. But I didn't find mine worn till I did overhaul one completely and compared with other. I had been using my worn HHKBs without any complain untill that.

I found plungers got very fine gray powder other than dust. I guess the powder is what plunger is filed down with housing.
I needed to break down completely to clean and lubricate plunger and housing. This is very time consuming job but worth trying.
I think overhauled pro is smooth as new pro2 is.

[hasu]

I'd  recommend to use dry lub neither grease nor oil.
I used RO-59(water-based lub) though it will not be available in your country.
But I think you can find good alternative.

EDIT: To lubricate and clean thoroughly you need to remove plungers from housing.

[limmy]

Thanks for the info, hasu.

I have KG8 at hand, solvent + PTFE powder, so I guess I could make my own RO-59 by drying the solvent then adding water. (I wonder if it is that simple though..)

I took out all the plungers and washed them. I think it may have been the grey powder that was causing the problem. Silicone oil may have mitigated problem temporarily, but the problem could have come back unless washed.

I have one question. Where would you apply the dry lube? Do you recommend any particular place that works well? Do I apply them on the plungers only?

I think I saw one post in KBDMania or OTD that you would pour KG8 into a bag and put plunger together and then shake. Would you recommend that method?

Thanks!

I'd  recommend to use dry lub neither grease nor oil.
I used RO-59(water-based lub) though it will not be available in your country.
But I think you can find good alternative.

EDIT: To lubricate and clean thoroughly you need to remove plungers from housing.

[hasu]

I have one question. Where would you apply the dry lube? Do you recommend any particular place that works well? Do I apply them on the plungers only?

I think I saw one post in KBDMania or OTD that you would pour K-8 into a bag and put plunger together and then shake. Would you recommend that method?

I applied cylinder part and foot of plunger, and hole and foot rail of housing. Namely I think you'd better apply all of sliding surface.
And I applied it twice with small brush one by one, it is very PITA work.

Though I don't know that dunk method  I don't recommend to apply PTFE to part not needed.

[limmy]

Thanks for the advice. I would try that after I make my custom RO-58 derived from KG-8. I think your method will have longer lasting effect than the dunk method.

Since I didn't have time and right tools, I did quick and dirty way (the dunk method to the plungers) and it seems to work pretty well. I don't know how long the effect would last, but so far it feels quite different compared to before. I think the static friction part is pretty much gone. I think washing off silicone oil and the powdery substance off of the plungers did most of the job. I couldn't apply KG-8 to the housing because the solvents eats away ABS plastics. The solvents didn't have any noticeable effect on the plungers.

After all this effort, however, the actuation force measurement using nickels (ripster calls it RipOmeter) is still at 65g for the keys to actuate. No change in the measurement before and after lubrication suggests that the friction in the sliders aren't really reflected in the actuation force measurement using weights. I am guessing big part of friction felt by human hands is static friction and it cannot be measured in an easy way using simple tools such as nickels.

I applied cylinder part and foot of plunger, and hole and foot rail of housing. Namely I think you'd better apply all of sliding surface.
And I applied it twice with small brush one by one, it is very PITA work.

Though I don't know that dunk method  I don't recommend to apply PTFE to part not needed.

[hasu]

[Hmm... some posts in this thread are lost due to the cracking incident...]

http://www.kbdmania.net/xe/index.php?mid=tipandtech&document_srl=3462221

Mmm, undestructive water and salt test is very interesting. Thanks for the info.
I want to try the test on HHKB/Realforce's space bars before too long and on plunger and housing when I have enough time.

I found specific gravity of other plastics in; http://www.imagro.co.uk/pdfs/LUMILOY%20componts%20combined.pdf
ABS: 1.05
PS: 1.05
PPE: 1.06
PC: 1.2
PBT: 1.31
PA: 1.14
PPS: 1.34
POM: 1.41

[limmy]

Hmm... I thought for sure I posted the answer before the server crash.

Yes, you did say something about testing plastics with a hammer, but you never answered the question. You may have answered it later in a follow up post, but I didn't see it before the crash. I mentioned to you about different physical characteristics of plastics (specific gravity, wear rate, coef of friction), and you said you would include the info in the all about key wiki. Boy, I am surprised I could remember so much.

So, is the Realforce switch housing ABS plastic ripster?

[limmy]

[Hmm... some posts in this thread are lost due to the cracking incident...]

http://www.kbdmania.net/xe/index.php?mid=tipandtech&document_srl=3462221

Mmm, undestructive water and salt test is very interesting. Thanks for the info.
I want to try the test on HHKB/Realforce's space bars before too long and on plunger and housing when I have enough time.

I found specific gravity of other plastics in; http://www.imagro.co.uk/pdfs/LUMILOY%20componts%20combined.pdf
ABS: 1.05
PS: 1.05
PPE: 1.06
PC: 1.2
PBT: 1.31
PA: 1.14
PPS: 1.34
POM: 1.41

I didn't know this part of the post was recovered.

I have written a summary about physical properties of plastics in Korean here. I have started to write/translate in English about what I have found so far on plastics and their implication on the sound and feel of keys.. And here are some facts that may be relevant to this thread.

Physical characteristics :

Specific gravity (reference1)
ABS: 1.05 g/cc (average), range 0.350 - 1.35 g/cc
PBT: 1.32 g/cc (average), range 1.07 - 1.63 g/cc
POM: 1.42 g/cc (Dupont Derlin)
Note - average and range are of ABS/PBT plastics reported in matweb.

Water absorption (reference1)
ABS: 0.399 % (average), range 0.0500 - 2.30 %
PBT: 0.267 % (average), range 0.000 - 1.09 %
POM: 0.200 %
Note - average and range are of ABS/PBT plastics reported in matweb.

Wear rate (reference2)
ABS: approx. 700
PBT: approx. 40
POM: approx. 12
Note - This figure has been approximated from a chart in reference2.

Coefficient of friction (reference2)
ABS: approx. 0.35
PBT: approx. 0.25
POM: approx. 0.21
Note - This figure has been approximated from a chart in reference2.

reference1 :
ABS - http://www.matweb.com/search/DataSheet.aspx?MatGUID=eb7a78f5948d481c9493a67f0d089646
PBT - http://www.matweb.com/search/DataSheet.aspx?MatGUID=781bd0e9d0854fd5a919866c39ea3065
POM - http://www.matweb.com/search/datasheet.aspx?matguid=1c7bd162dfc84628892fffc7fb1dbc88

reference2 :
http://plastics.dupont.com/plastics/pdflit/europe/delrin/DELLWLFe.pdf

[fossala]

Does that mean pom is the best not pbt?

[HaiiYaa]

Does that mean pom is the best not pbt?

should be more durable but it doesnt feel better than pbt imo. Not that pbt keycaps will wear out anyway

[limmy]

Added to my Ripster 2012 ToDo list.  #40.

Might be a while.

Taxes take priority.

Boy the Alpsulator is a fun calculator to use for taxes.

See sig for details or just google "ALPSulator".

Benevolent one, would you find out if the slider housing of Realforce is indeed ABS?

HHKB slider housing is made of ABS plastic as well as the slider housing of stabilizers for spacebar. The upper housing of HHKB says it is ABS plastic and I tested the stabilizer housing with a little swipe with acetone (it left a mark)

[limmy]

Thanks for checking.

I don't recommend KG-8 for Topres then!

KG-8 worked pretty well when applied to sliders only. However, I don't recommend using them because the lubricant wore off quite quickly.

[limmy]

Here is why I think plastic material used in sliders and slider housing is important. I mentioned in a previous post(see here), but didn't post the actual chart.

Here it is.
Original chart from Dupont document
[ Attachment Invalid Or Does Not Exist ] 45269[/ATTACH]
The same chart replicated in Excel to get numbers below
[ Attachment Invalid Or Does Not Exist ] 45268[/ATTACH]

Wear rate (reference2)
ABS: approx. 700
PBT: approx. 40
POM: approx. 12
Note - This figure has been approximated from a chart in reference2.

Coefficient of friction (reference2)
ABS: approx. 0.35
PBT: approx. 0.25
POM: approx. 0.21
Note - This figure has been approximated from a chart in reference2.

reference2 :
http://plastics.dupont.com/plastics/pdflit/europe/delrin/DELLWLFe.pdf

This is why ABS plastic is not recommended where friction is of concern.

Here are what I find on different switches:
1. HHKB: HHKB housing is made of ABS plastic and the housing acts as slider housing. Topre switch's slider is not ABS, it seems to me they are pretty similar to POM and coated with some kind of lubricant out of factory.
2. Membrane keyboards: Pretty much all membrane keyboards have ABS plastic housing and sliders.
3. Cherry: Cherry switches' slider housing use PBT(saw this at Cherry wiki) and sliders seems to be some sort of slick plastic(I am guessing they are either POM or PBT, but certainly not ABS because they do not react to acetone.)
4. Alps:Alps switches' slider housing is made from ABS. Again, not sure about slider but certainly not ABS.
5. What about realforce? -- This is my question.

side note: I compared sliders of Cherry Reds and Browns, and it seems browns have more slick surface. (I scratched surface with my finger nail to compare) I am suspecting that the slider material has changed over time. I heard sliding surface of Cherry blacks are similar to that of browns. This is why many Korean keyboard enthusiasts mod blacks and swap springs (they use custom springs), and avoid red sliders for their mods.

I do not have enough information to conclude that there is causal relationship between the material used and durability, but I am pretty certain that there is strong correlation between the two. Membrane keyboards develop friction quite quickly. Alps switches are said to be not so durable. Topre switches have shorter life than Cherries(it may be in part due to rubbers too). Cherry switches have longest life thanks to more slick and durable material used.

[tp4tissue]

Here is why I think plastic material used in sliders and slider housing is important. I mentioned in a previous post(see here), but didn't post the actual chart.

Here it is.
Original chart from Dupont document
(Attachment Link) 45269[/ATTACH]
The same chart replicated in Excel to get numbers below
(Attachment Link) 45268[/ATTACH]




This is why ABS plastic is not recommended where friction is of concern.

Here are what I find on different switches:
1. HHKB: HHKB housing is made of ABS plastic and the housing acts as slider housing. Topre switch's slider is not ABS, it seems to me they are pretty similar to POM and coated with some kind of lubricant out of factory.
2. Membrane keyboards: Pretty much all membrane keyboards have ABS plastic housing and sliders.
3. Cherry: Cherry switches' slider housing use PBT(saw this at Cherry wiki) and sliders seems to be some sort of slick plastic(I am guessing they are either POM or PBT, but certainly not ABS because they do not react to acetone.)
4. Alps:Alps switches' slider housing is made from ABS. Again, not sure about slider but certainly not ABS.
5. What about realforce? -- This is my question.

side note: I compared sliders of Cherry Reds and Browns, and it seems browns have more slick surface. (I scratched surface with my finger nail to compare) I am suspecting that the slider material has changed over time. I heard sliding surface of Cherry blacks are similar to that of browns. This is why many Korean keyboard enthusiasts mod blacks and swap springs (they use custom springs), and avoid red sliders for their mods.

I do not have enough information to conclude that there is causal relationship between the material used and durability, but I am pretty certain that there is strong correlation between the two. Membrane keyboards develop friction quite quickly. Alps switches are said to be not so durable. Topre switches have shorter life than Cherries(it may be in part due to rubbers too). Cherry switches have longest life thanks to more slick and durable material used.

Damn it, this sort of is convincing me NOT to buy a HHKB,, I am still very close to doing it.

[limmy]

Topres less durable than Cherry MX?  Oh well.  life IS temporal.

P.S. I do not remember Topre main cluster sliders being lubed from the factory.  Unfortunately I can't post pics.

Sent From Brother Ripster's iPad

Photo evidence doesn't tell much of a story about lubrication if it is not visually detectable. Any decent membrane is lubed out of factory. In order to test this hypothesis, all you need to do is wash it with soap and warm water.

I will post photos when I get a chance comparing old and new sliders. I don't have plans to wash my like-new slider for the purpose, but if you are curious you are more than welcome to try the washing testing method out if you firmly believe that Topre slider is not lubed.

Damn it, this sort of is convincing me NOT to buy a HHKB,, I am still very close to doing it.

It is still nice switch and my first choice. But without proper care, I am guessing three years of daily use will leave with somewhat sticky HHKB. (By sticky, I mean resistance to be depressed when you press corners of certain keys.) I had no issues up until about two years. I didn't feel a need to do anything to my HHKB back then.

I would like to see improved plastic material in the next version of HHKB as well as firm ware update feature seen in many Korean customized keyboards. There are couple of versions of customized keyboards featuring customization of up to two layers with hardware programming(meaning there is no need for software once you set up the customized layout.)

PBT space bar will be also nice.

[limmy]

I tested the plastic used for the switch housing. It seems to be ABS plastic because acetone swipe left a mark. This result confirms that Realforce and HHKB use the same materials for their switches. There is no reason to believe RF will last longer than HHKB as I conjectured before, although switch feel may be a little different due to different material used for the plate: RF use metal plate and HHKB use ABS plastic.

As noted before, ABS plastic is not a best material to use when friction is of concern. It is probably why the sliders are lubricated out of factory. The smooth feel is probably due to the lube too, which will eventually wear out after prolonged use.