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geekhack Community => Keyboards => Topic started by: wellington1869 on Mon, 27 July 2009, 12:22:06

Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 12:22:06
Ok, here's a question.

Seeing the switch poll in the other thread, I was suprised that blue cherries are so far ahead. Seems to me that with each passing year the old IBM BS system will have fewer and fewer fans. Since a lot of the fandom there is driven by nostalgia, I have to admit.  For modern users, probably BS are really too stiff (even tho they're not stiff in comparison to what old folks are used to, typewriters and older keyboards, where something around 60g of resistance seems to be the norm). These days if you're over 45g of resistance people describe it as stiff.

So, question:

Is there a way to lighten the BS spring?
Possible solutions:
a) find a replacement spring with less tension? This may be difficult unless custom built (and so prolly expensive).

b) Would the springs lighten if, say, stick the keyb under a coffee table for two weeks with all the keys in a depressed state?

c) Here's a radical idea: get some relatively mild metal-eating acid. soak the BS springs in it for short periods of time. Would this "thin out" the springs just enough to reduce resistance by, say, 10g? (around 50g resistiance might be ideal for the "BS-light").

Any other ideas or comments on the above? How to get from point A to point B in this case?
Title: how to lighten BS springs?
Post by: itlnstln on Mon, 27 July 2009, 12:25:16
If there were a lighter BS, I would be all over it (that is, if it were around <= 50g). I really like buckling springs, but as Wellington said, some find them too stiff, and I do.
 
I wonder if Unicomp could help...
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 12:37:35
I wonder how much it would cost to approach a spring-maker and give them a bs sample and say "reproduce this but lighten this to 50g and we'll take 1000 springs".
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 12:38:40
I wonder if (b) would work. Anyone want to try it? Use rip-O-meter before and after the coffee table.
Title: how to lighten BS springs?
Post by: talis on Mon, 27 July 2009, 13:10:51
Changing the spring may ultimately result in not enough pressure being put on the membrane by the foot when the spring does buckle, and may result in missed keystrokes.  At least on a model M, a model F is more likely to keep working properly even with a spring change.

You'd also likely loose some of the sound, and the tactile feel with a softer spring.

Its possible that it will work, but I suspect that IBM designed the keys with that weight for a reason (since it seems its heavier then some of their earlier typewriter designs).
Title: how to lighten BS springs?
Post by: ch_123 on Mon, 27 July 2009, 13:45:44
I must get my hands on this dry teflon stuff and try using it on my Model F. Even though it's lighter than a regular BS board, I'd like it to be even lighter still.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 14:31:30
can someone do rip-O-meter on the F? Is it really lighter than M?  By at least 10g?

And if its lighter by 10g or so, has anyone replaced M springs with F springs?

Edit:  Caught up with the converstaion on the other thread. Apparently you'd need a longer barrel on the M to just swap springs.

But -- since its the longer spring of the F that is creating a softer feel -- what if:

d) You cut the M spring by a quarter inch, then stretch it to make it longer.  Would that equal a softer M?
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 14:36:35
Quote from: ripster;104735
Here's a list (http://home.earthlink.net/~bazillion/resources.html) of spring manufactures sorted by County and State.

The specs for the IBM Model M springs are kinda here (http://geekhack.org/showpost.php?p=104600&postcount=40) but don't quote me on the wire diameter part.


its funny, i used to live right next door to a small factory that had a sign that said something like "manufacturer of springs and coils" and I always thought it was funny super-niche market. [after all, someone is making those ball point pen springs!]. Of course if I were still living there today I'd just run over with Bs spring in hand ;)
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 14:38:22
Quote from: talis;104736

You'd also likely loose some of the sound, .


might not be a bad thing for modern users. Though i wouldnt want the bs to become totally blue-cherry like.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 14:48:47
Quote

Your mind follows strange paths.


I still like my metal-eating-acid-bath idea too ;D
Title: how to lighten BS springs?
Post by: itlnstln on Mon, 27 July 2009, 14:49:18
Quote from: ripster;104773
I'll try that sometime. While doing the rivet mod I managed to bend a spring over the barrel. It was so slight I didn't think it would matter but a slight bend basically rendered the spring useless - it wouldn't buckle! I ended up swapping springs using Sandy's method that you posted - I took one from my son't Unicomp ScrollLock. Those suckers are easy to put in but hard to pull out without bending.

Another abuse for the Boscom.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 15:16:04
Also,
e) out of curiosity, how about putting in springs from other keyboards (like a black alps board) by stretching those springs? How would it feel? (similarly, surely there is a cheap ballpoint pen out there that has thin diameter springs that we could stretch out?). Or similarly, surely a manufacturer of springs and coils would have a "catalog" of standard springs from which we could choose one that comes close to what we're looking for? (Stretching it a bit if necessary).
Title: how to lighten BS springs?
Post by: timw4mail on Mon, 27 July 2009, 16:45:41
I never thought about how complex the mechanism really is...
Title: how to lighten BS springs?
Post by: ch_123 on Mon, 27 July 2009, 17:46:40
Quote from: wellington1869;104767
can someone do rip-O-meter on the F? Is it really lighter than M?  By at least 10g?

I did it, it's in the 60-65g region. It's hard to get an accurate reading on BS keys, also, spring wear could lower the resistance. Hard to tell which figure is more accurate.

Quote
Edit:  Caught up with the converstaion on the other thread. Apparently you'd need a longer barrel on the M to just swap springs.


That's entirely an estimation on my behalf, I figure that the barrel is sized so that there's a snug fit between keycap and spring. If anyone wants to try, they could probably get their hands on a cheap XT Model F, and try swapping with a Model M.

Quote
But -- since its the longer spring of the F that is creating a softer feel -- what if:

d) You cut the M spring by a quarter inch, then stretch it to make it longer.  Would that equal a softer M?

The thing about the F is that it's not just a soft Model M, the tactility and bounce-back of the keyswitch is far more pronounced. I think if you did that that you'd just end with a mushy feeling Model M. They offer a completely different typing experience, as Webwit once said - they're like Blue Cherrys done right.

Quote
Also,
e) out of curiosity, how about putting in springs from other keyboards (like a black alps board) by stretching those springs? How would it feel?

Once upon a time, before I abandoned the UK ISO layout, I had a worn out Dell AT102W. I got one of those infamous $5 NIB AT101Ws and transferred the switches from one keyboard to the other. Once I had finished, I was playing around with the old worn out ones, I accidentally bent one spring. I tried to fix it by streching it out, but it wouldnt go back to it's old shape when I pushed it back in, instead, I ended up with something that looked like two Topre springs stuck together at the wide end. I put this into a switch and assembled it into the spare PCB. It had an interesting feel, it was stiff and linear. I tried to recreate it, but the second one didnt turn out right, probably one of those fluke chances.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 18:20:06
thanks for the info CH. IIRC, the M's are about 65-70g, so I guess the F's are about 5g or so lighter then. I'd like to bring them down to 50g :)
Title: how to lighten BS springs?
Post by: timw4mail on Mon, 27 July 2009, 18:49:50
Quote from: wellington1869;104837
thanks for the info CH. IIRC, the M's are about 65-70g, so I guess the F's are about 5g or so lighter then. I'd like to bring them down to 50g :)

My only real issue with the spring strength is the tendency to make one's fingers bounce too much in normal typing. What are the linear Cherry's force rating? That seems to be a pretty good strength.

(Of course that might be 50g, I'm not sure.)
Title: how to lighten BS springs?
Post by: ch_123 on Mon, 27 July 2009, 19:06:37
Quote from: timw4mail;104845
My only real issue with the spring strength is the tendency to make one's fingers bounce too much in normal typing. What are the linear Cherry's force rating? That seems to be a pretty good strength.

(Of course that might be 50g, I'm not sure.)


Linear Cherrys are about 60g if memory serves me correct. From my experience with old 1970s and early 1980s linears, the lighter the better. They're rather strange to type on, you'd get used to it after a while, but I'd say you'd miss the tactility.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 20:26:27
Quote from: ripster;104849
Blue Cherries are 50g.  Not too stiff, not too light.  Might have something to do with it leading in the poll.


are you sure about that? Crap, maybe i need to try blue cherries again, lol.
Title: how to lighten BS springs?
Post by: Rajagra on Mon, 27 July 2009, 20:33:52
Quote from: wellington1869;104706
Is there a way to lighten the BS spring?


How about adding weights into the keycaps? Should give an interesting feel!
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 27 July 2009, 20:37:31
Quote from: Rajagra;104884
How about adding weights into the keycaps? Should give an interesting feel!


thats an interesting idea. tho I think while downstroke may get easier upward bounce would suffer too. Would be interesting to try it though.

I sort of had this idea when I put what I think are the heavier M keys and stems onto my endurapro, tho the weight difference couldnt have been that much really. It did affect tonal sound though (the thicker old plastics have a lower tone, which I like).

They do sell this epoxy-like weighting glue (I think they use them on model airplanes). Would be trivial to pour some of that into the underside of the keycap, if someone wanted to try it with an old board.
Title: how to lighten BS springs?
Post by: talis on Mon, 27 July 2009, 22:25:09
Thanks to this (http://geekhack.org/showwiki.php?title=Island:6490) thread (and an upcoming mod) I have a bucket of springs and keys to play around with.  I'll see what I can come up with to test some of these ideas.
Title: how to lighten BS springs?
Post by: wellington1869 on Tue, 28 July 2009, 01:06:11
Quote from: talis;104917
Thanks to this (http://geekhack.org/showwiki.php?title=Island:6490) thread (and an upcoming mod) I have a bucket of springs and keys to play around with.  I'll see what I can come up with to test some of these ideas.


that would be awesome talis
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 28 July 2009, 08:11:47
Cherry blacks start at 40g and finish at 80g; they are a pretty heavy switch. I think spring bounce doesn't have as much to do with key spring/resistance as one might think since it seems rather logical. All the Alps keyboards I have/had do not spring back after the keystroke like all of my Cherry brown keyboards do, and the Cherry brown is a significantly lighter switch. This was one of the reasons why Chloe was such a Cherry fan. When you start to learn how to type light enough, the Cherrys help you out by pushing your finger back up off the key. The Alps only seemed to have enough force to push the key back up and that was about it. There has to be something with the materials used in the spring, the way the spring is coiled, and maybe the weight of the stem of the switch that also determines how bouncy a switch feels.
Title: how to lighten BS springs?
Post by: ch_123 on Tue, 28 July 2009, 08:19:40
Quote from: itlnstln;104972
When you start to learn how to type light enough, the Cherrys help you out by pushing your finger back up off the key. The Alps only seemed to have enough force to push the key back up and that was about it.


QFT. I can type fastest on my blue Cherry board.

For any Topre users out there - how much bounce-back is there in those switches?
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 28 July 2009, 09:49:02
Quote from: ripster;104999
Yep, that's what I'm feeling on this AT101W - it makes it feel at least as much work to type as a Buckling Spring if not more.

Even though the Alps switches are lighter than BS, this phenomenon give them the perception (and, perhaps, the reality) that they require more work than BS.
Title: how to lighten BS springs?
Post by: wellington1869 on Tue, 28 July 2009, 10:42:20
Quote

Cherry blacks start at 40g and finish at 80g


"like a hard bit of jello" -- chloe
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 28 July 2009, 10:51:20
I miss Chloe and Sandy.
Title: how to lighten BS springs?
Post by: ch_123 on Wed, 29 July 2009, 13:31:24
According to Sandy's home page, the 5576-A01, which is generally considered to be stiffer than the Model M, has shorter springs. Seems to back up this theory further.

Ripster - how much do those coins weigh again?
Title: how to lighten BS springs?
Post by: itlnstln on Wed, 29 July 2009, 13:46:42
Quote from: ch_123;105268
Ripster - how much do those coins weigh again?

5g each.
Title: how to lighten BS springs?
Post by: ch_123 on Wed, 29 July 2009, 13:48:01
I count 16... So you managed to raise the resistance to 80g?
Title: how to lighten BS springs?
Post by: timw4mail on Wed, 29 July 2009, 13:59:12
Quote from: ch_123;105279
I count 16... So you managed to raise the resistance to 80g?

That's what it looks like. Apparently, you need springs of the same diameter and length with more coils for a weaker spring...weird.
Title: how to lighten BS springs?
Post by: ch_123 on Wed, 29 July 2009, 14:02:46
Yeah, the M and F springs are definitely the same diameter - there's just more 'spring' on the F.
Title: how to lighten BS springs?
Post by: wellington1869 on Wed, 29 July 2009, 14:06:03
lol, thanks for the experiment, rippy!  80g, eh? hmmmm.
I'd stick mine under the coffee table but I only have one working M and I dont want to ruin it!  Someone who has some spare boards will have to try....

Quote

Just as soon as you think you understand the Buckling Spring the thing gets all random on you

god thats the truth (or: GTTT).
Title: how to lighten BS springs?
Post by: wellington1869 on Wed, 29 July 2009, 15:46:03
its a real conundrum.  I still think we might be able to find a replacement lighter spring from a standard spring-parts catalog from a manufacturer. maybe a google search is in order...
Title: how to lighten BS springs?
Post by: timw4mail on Wed, 29 July 2009, 15:47:55
Quote from: ripster;105326
What do I do to make it softer?? No acid spring bath for me nosiree..... End up looking like Phantom of the Opera.

I think you have to get "denser" springs
Title: how to lighten BS springs?
Post by: wellington1869 on Wed, 29 July 2009, 15:53:09
anyone with a spring in hand want to post diameter and length and a closeup pic of the ends?  I can search google once I have the info... (of course i could pull one out of my M but as I say its working fine and I'd rather not mess with a single working board...). If anyone has any broken or spare boards on the other hand maybe you wouldnt mind yanking a spring out and letting us know what to look for...
Title: how to lighten BS springs?
Post by: JBert on Wed, 29 July 2009, 16:06:25
Quote from: ripster;104720
Your mind follows strange paths.  I was thinking of a blowtorch on the springs but couldn't remember if that makes steel harder or softer. So then I found a WHOLE SITE dedicated to DIY springs (http://home.earthlink.net/~bazillion/intro.html) written in English no less.  I started reading it before deciding I was going off the deep end.
It's all there:
Quote
There are three basic principles in spring design:

    * The heavier the wire, the stronger the spring.
    * The smaller the coil, the stronger the spring.
    * The more active coils, the less load you will have to apply in order to get it to move a certain distance.

Based on these general principles, you now know what to do to change the properties of a spring you already have. For instance, if you want to make automotive valve springs a little stronger than stock, you can a) go to a slightly heavier wire and keep the dimensions and coil count the same, b) decrease the diameter of the spring, keeping the wire size and coil count the same, or c) decrease the number of active coils, keeping the wire size and spring diameter the same. Naturally, you can also go to a stronger material to achieve the same result.
So we simply need to do the exact opposite of the above. Simple... or not.

 If you got room to spare inside the barrel, you could try to increase the diameter of "working part" the spring. However, this may shorten the spring seeing how you have less wire to spare and may not leave enough room for the spring to buckle.

Tempering the springs may work - they should become softer when warmed. Their hardness mainly depends on the cooling rate. If you would swiftly submerge them in water when hot, they'd probably be stiffer and less elastic. On the other hand, slowly cooling them in some ceramic enclosure may give an elastic but really soft spring.

Probably test it on some spare springs you have around, e.g. from some ballpens you never use.


Anyway, don't forget to measure the required force on the feet first, a buckling spring with not enough force to make the contact is also useless.
Title: how to lighten BS springs?
Post by: talis on Wed, 29 July 2009, 16:18:19
Quote from: wellington1869;105291
lol, thanks for the experiment, rippy!  80g, eh? hmmmm.
I'd stick mine under the coffee table but I only have one working M and I dont want to ruin it!  Someone who has some spare boards will have to try....


I'm pretty sure the time frame required to get any appreciable change in doing this would be rather long.

I plan to introduce Mr. Model M to Mr. Tablesaw this Friday, and get a jig together to test some of these ideas.

I think outside of changing the springs entirely, tempering may be the best approach, I'm just not sure how easy it will be to get a consistent result.
Title: how to lighten BS springs?
Post by: wellington1869 on Wed, 29 July 2009, 16:26:46
Quote from: ripster;105348


I'll try the propane torch trick and throwing them into a preheated oven to cool down.   If it work's I'll just fire up the Barbie (as the Aussies say) and do a couple hundred of them!


you could do a nice little side business roasting springs for people who want this mod :)

Quote

I plan to introduce Mr. Model M to Mr. Tablesaw this Friday


now that sounds like fun :)


I still say a stock part must be out there for this...
Title: how to lighten BS springs?
Post by: talis on Fri, 31 July 2009, 21:50:41
The bandsaw won:

(http://geekhack.org/attachment.php?attachmentid=3505&stc=1&d=1249095004)
Title: how to lighten BS springs?
Post by: talis on Sat, 01 August 2009, 11:44:55
Working on it.
(http://geekhack.org/attachment.php?attachmentid=3514&stc=1&d=1249145074)
Title: how to lighten BS springs?
Post by: BucklingSpring on Sat, 01 August 2009, 11:56:34
Quote from: Rajagra;104884
How about adding weights into the keycaps? Should give an interesting feel!


That's exactly what I was thinking too. But it will change the inertia of the keys. Fast typists like some of you may find them too slow to return to position.
Title: how to lighten BS springs?
Post by: BucklingSpring on Sat, 01 August 2009, 12:19:14
Quote from: ripster;105262

As my son loves to say, "Epic Fail".   Just as soon as you think you understand the Buckling Spring the thing gets all random on you.


I’m by no mean a spring expert but I know a little about them.
You need to be careful when you play with spring limits:

Elastic limit: Maximum stress to which a material may be subjected without permanent set.

Endurance Limit: Maximum stress at which any given material will operate indefinitely without failure for a given minimum stress.

Permanent set: A material that is deflected so far that its elastic properties have been exceeded and it does not return to its original condition upon release of load is said to have taken a "permanent set."

Unless you are a metal alloy engineer, you will have a hard time to predict the effect of stretching the spring to a permanent set. Heating the spring is not a good idea either. It will destroy the tempering and its elasticity.

Anyone knows a good old clockmaker? These guys have connections for small springs.

And I’m sure the folks at Unicomp will be welling to share the buckling spring specs.
Title: how to lighten BS springs?
Post by: ch_123 on Sat, 01 August 2009, 19:17:55
Quote
There are three basic principles in spring design:

* The heavier the wire, the stronger the spring.
* The smaller the coil, the stronger the spring.
* The more active coils, the less load you will have to apply in order to get it to move a certain distance.


Yeah, there are going to be some problems here. If you make the spring of too lightweight a material, it's going to wear out too easily, you can only make the spring so long before you start having to super-size the barrels and then the key size, so it seems we need more coils on the springs, but it's quite a tight squeeze as it is...

So, any experts on Nanotechnology here? =P
Title: how to lighten BS springs?
Post by: BucklingSpring on Sat, 01 August 2009, 19:25:22
Quote from: ripster;106112
Maybe my son and I will try samurai swords next.


With all the comprehensive work you've done already, you must be ranking up there with the best masters in the art of swordsmanship.

It just took centuries of trial and error after all. But back then, they didn't have all the sciences you have. You got an edge on them for sure.

ROFL...

Thank you for making my day again. I was in desperate need of a good laugh.
Title: how to lighten BS springs?
Post by: wellington1869 on Sat, 01 August 2009, 21:57:46
ripster, what a great experiment. The slow cool one seems so close! What would happen if you only heated it to, say, 300 degrees? or 200? would that keep the force around 55g? (and therefore a better buckling feel)?
Title: how to lighten BS springs?
Post by: huha on Sat, 01 August 2009, 22:20:07
Quote from: ripster;106033
Some people claim they can feel the difference in two piece keys versus one - I couldn't in my limited testing (although I will get another M Space Saving with two piecers so it'll be easier to tell).


I could definitely feel a difference between my Boscom and my Endurapro; the former does feature two-piece keycaps, but I'm not exactly sure if this makes for all the differences in feel.

-huha
Title: how to lighten BS springs?
Post by: ch_123 on Sun, 02 August 2009, 06:39:03
Quote from: huha;106143
I could definitely feel a difference between my Boscom and my Endurapro; the former does feature two-piece keycaps, but I'm not exactly sure if this makes for all the differences in feel.

-huha


To me, it feels like the two piece caps dampen or absorb some of the tactility of the key.
Title: how to lighten BS springs?
Post by: wellington1869 on Sun, 02 August 2009, 15:19:16
so ripster, if 50g is too light for bs, what do you think is an ideal 'light' bs? 55g?
would it be possible to produce 55g by adjusting the temperature of the 'roast'?
Title: how to lighten BS springs?
Post by: wellington1869 on Sun, 02 August 2009, 15:53:03
Quote from: ripster;106243

Anybody have any luck finding a substitute online?  Lots of springs out there.  You can use one of my pics to count windings.



can you tell me the dimensions of the spring? (I guess in mm?)
Title: how to lighten BS springs?
Post by: wellington1869 on Sun, 02 August 2009, 16:19:08
thanks, i'll see what i can find out there...
Title: how to lighten BS springs?
Post by: wellington1869 on Sun, 02 August 2009, 23:30:45
ok, these two sites (recommended at an RC hobby site) look really promising (for small parts in general, including things like O-rings):

http://www.smallparts.com/
http://www.mcmaster.com/#

I just started poking around there right now...

update: ok, mcmaster has a size spring that is pretty close (http://www.mcmaster.com/#9435k13/=30sreu) but the load resistance is way too high (around 1 lbs). But reason for optimism: price is about $6 for pack of 5.
for reference thats Part Number:  9435K13

update: at the smallparts.com site, the closest one I found is this:
http://www.smallparts.com/Stainless-Steel-Inst-Spring-Length/dp/B001DID5FK?ie=UTF8&qid=1249274526&pf_rd_r=1ZEDQM08DEMAFSXXHHWC&pf_rd_p=467590031&pf_rd_i=0&sr=1-51&pf_rd_s=center-3&pf_rd_m=AIUBT5HP6PMAF&pf_rd_t=301
basically its dimensions are right, but I dont know if the resistance is right. The only resistance listed is a "spring rate" of .8 inch-pounds.  I havent a clue what that means. When you convert 55g (an example 'target' resistance) to lbs, it comes out as .1212 lbs.  But is that the same as 'spring rate'? I doubt it. So I'm not sure what to ask for even if I called them. Any ideas?

IN terms of all the other dimensions (wire thickness, length, and width), the spring is in the ballpark.
Title: how to lighten BS springs?
Post by: JBert on Mon, 03 August 2009, 09:36:05
Quote from: ripster;106249
Here it is (http://geekhack.org/showpost.php?p=104600&postcount=40) in inches.

Unicomp oddly enough is exactly the same.  Coil count too.  May be a slightly different metal though.   Other factor is the foot - different plastic - I need to do a more complete comparison there.
Indeed, if the wire diameter, spring size and coil count are the same, the only thing remaining is the spring material (or there was a measure error when looking at the wire diameter).

Do they make their springs themselves? If so, they can probably tell if they changed the type of steel.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 09:44:35
well it doesnt look like cost will be an issue, most of the "replacement springs" i've seen so far have been relatively affordable (about a dollar per spring).
Title: how to lighten BS springs?
Post by: timw4mail on Mon, 03 August 2009, 09:45:46
That can get rather expensive when you're replacing 101 springs, though.
Title: how to lighten BS springs?
Post by: timw4mail on Mon, 03 August 2009, 09:49:01
Quote from: ripster;106400
I got the impression from that DIY Spring site that most small springs are made of "music" steel.  The same stuff in my guitar strings.  Probably SOME variance though.

Yeah, I was going to comment on the cost.  My $20 Boscom will net me 122 springs - that is the cheapest deal going if you wanted to renovate an old mushy M.

I can't imagine that the consistency of the spring steel would have been a very important factor for IBM/Lexmark/Unicomp. Its like plastics, you have a slightly different batch each day that in the end performs about the same.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 12:03:41
Quote from: timw4mail;106399
That can get rather expensive when you're replacing 101 springs, though.


true, though personally i'd only replace the main alphabet cluster. so i'd spend about 30 bucks. I dont think its worth doing it for all 104 keys unless i had that kind of disposable income.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 12:04:51
i'd order some to try but I'd like to know more about its resistance. I'm too unfamiliar with the terminology being used to indicate the resistance levels. Need to find out more.
Title: how to lighten BS springs?
Post by: talis on Mon, 03 August 2009, 15:48:32
I just took a few measurements of the springs from my 401.

Length : 18.5mm
OD : 2.75mm
ID : 2mm
Wire dia : .18mm (33 gauge)
Buckling point : 4.8mm compression @ 68g

As far as I could measure, the compression force seems to be fairly linear at about 15g/mm
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 15:53:44
Quote from: talis;106610
I just took a few measurements of the springs from my 401.

Length : 18.5mm
OD : 2.75mm
ID : 2mm
Wire dia : .18mm (33 gauge)
Buckling point : 4.8mm compression @ 68g

As far as I could measure, the compression force seems to be fairly linear at about 15g/mm


talis, can you take a look at this link (http://www.smallparts.com/Stainless-Steel-Inst-Spring-Length/dp/B001DID5FK?ie=UTF8&qid=1249274526&pf_rd_r=1ZEDQM08DEMAFSXXHHWC&pf_rd_p=467590031&pf_rd_i=0&sr=1-51&pf_rd_s=center-3&pf_rd_m=AIUBT5HP6PMAF&pf_rd_t=301)? In terms of dimensions, I think its about the right size - but in terms of resistance level, I havent a clue.
Title: how to lighten BS springs?
Post by: talis on Mon, 03 August 2009, 16:29:12
Unless I screwed up the conversion (very possible) 15g/mm translates to about .83 lb/inch.  Seems to be almost exactly what that spring you linked was rated.

I used my jig, a dial indicator, and a scale to take those measurements so they may not be 100% accurate either.
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 16:30:57
Quote from: talis;106648
Unless I screwed up the conversion (very possible) 15g/mm translates to about .83 lb/inch.  Seems to be almost exactly what that spring you linked was rated.


hmmm, that would be a pity, because .83 was the lightest one they had. Wouldnt make any sense to get the exact same spring...

so the search continues I guess...

it might be worth getting one or two of those just to make sure. If we're lucky the compression characteristics would be slightly lighter (putting it in the 55-60g range). But tahts really just a shot in the dark I guess.
Title: how to lighten BS springs?
Post by: talis on Mon, 03 August 2009, 16:38:42
To compute the spring force (and I'd love it if someone would double check this math) you'd take the force you want and :

Force * [(25.44mm/inch)/(4.88mm * 453.59g/lb)]

That assumes the spring will buckle at exactly the same point (which is independent of the spring force as far as I can tell).

Theoretically to get 60g of actuation force you'd want a spring force of .689 lb/inch.  Again that assumes that it buckles at 4.8mm of compression (which is not really a safe assumption to make).
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 17:04:40
Quote from: webwit;106661
Hmm..
http://www.leespring.com/uk_intro_LP_compression.asp


fascinating. Who wants to buy-n-try? :D
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 17:13:49
oh they have a selector where you plug in mm and it tells you which spring to buy:
http://www.leespring.com/uk_compression_spec.asp?springType=C&forWhat=Search
Title: how to lighten BS springs?
Post by: timw4mail on Mon, 03 August 2009, 18:29:51
Hmm...I don't have the proper tools, but does anybody know the specs for the Model F springs?
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 18:35:34
so if no one wants to buy-n-try the light springs, am I going to have to sacrifice my only son, er, my only model M keyboard because I so loved the world (of keyboarding)?
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 18:39:36
Quote from: ripster;106705
I sacrificed a Boscom and managed to sleep fine.


yes but was it your only begotten boscom? this is my only begotten model M, and I will have to forsake it, and it will be set upon and killed,  verily.
Title: how to lighten BS springs?
Post by: talis on Mon, 03 August 2009, 21:53:33
Quote from: wellington1869;106706
yes but was it your only begotten boscom? this is my only begotten model M, and I will have to forsake it, and it will be set upon and killed,  verily.

Who knows, tearing it apart could motivate you to start working on your own mod!
(http://geekhack.org/attachment.php?attachmentid=3561&stc=1&d=1249354549)

(Still a work in progress).
Title: how to lighten BS springs?
Post by: wellington1869 on Mon, 03 August 2009, 22:05:32
Quote from: talis;106737
Who knows, tearing it apart could motivate you to start working on your own mod!
Show Image
(http://geekhack.org/attachment.php?attachmentid=3561&stc=1&d=1249354549)


(Still a work in progress).


thats beautiful :)

I dont need the arrow cluster either.

That with 60g springs = perfection?
Title: how to lighten BS springs?
Post by: lal on Tue, 04 August 2009, 07:18:48
Indeed, looks promising.  Now if you could make the cuts a) invisible and b) indestructible...
Title: how to lighten BS springs?
Post by: wellington1869 on Tue, 04 August 2009, 10:37:40
Quote from: lal;106796
Indeed, looks promising.  Now if you could make the cuts a) invisible and b) indestructible...


you could probably make it pretty undetectable if you fill the seam with caulk and paint over it.
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 04 August 2009, 10:55:18
Quote from: wellington1869;106849
you could probably make it pretty undetectable if you fill the seam with caulk and paint over it.

I would use something harder like Bondo.  That way you could sand it down and paint it a little easier.  Caulk would be too rubbery, I think.  The only thing that might be lacking with any method of filling and painting would be matching the texture of the original case.  That could be a whole new mod (refinishing/rebuilding the case).
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 04 August 2009, 10:56:18
I like the title of the pic, too.  The "Clacky Hacker."
Title: how to lighten BS springs?
Post by: talis on Tue, 04 August 2009, 11:40:43
Quote from: itlnstln;106862
I would use something harder like Bondo.  That way you could sand it down and paint it a little easier.  Caulk would be too rubbery, I think.  The only thing that might be lacking with any method of filling and painting would be matching the texture of the original case.  That could be a whole new mod (refinishing/rebuilding the case).

I'm using a 2 part epoxy putty.  Give a bit of structural strength that Bondo doesn't (it becomes less brittle when set).

http://polymericsystems.com/epoxies-adhesives/epoxy-putty-sticks/quikplastik.htm

Still a long way to go on it.
Title: how to lighten BS springs?
Post by: itlnstln on Tue, 04 August 2009, 11:43:26
Quote from: talis;106894
I'm using a 2 part epoxy putty. Give a bit of structural strength that Bondo doesn't.
 
Still a long way to go on it.

Good choice.  Epoxy putty is awesome stuff.  Especially when you have a leak in your car's radiator, and you're waiting for a replacement part.  
 
A little personal experience there.