deskthority

I recently bought a Leopold FC660C, which has 45-gram Topre switches. However, the spacebar has an auxiliary compression spring that fits around the outside stem of the switch. According to EK, this spring adds about 5 cN to the actuation pressure of the switch and also aids in the rebound of the spacebar. This spring can easily be removed and placed on other keys if desired. I like the slightly heavier feel of the spacebar, and I thought it could be a good idea to make all of the keys slightly heavier.

Therefore, would it be possible to do an "auxiliary spring mod" on a Topre board by acquiring a set of these 5 cN springs and installing them on each switch? The object would be an easy conversion of, say, a 45-gram Topre board to a 50-gram Topre board without resorting to the much more difficult method of swapping out the rubber domes. Furthermore, if one had 10 cN springs, the conversion should result in changing a 45-gram board to a 55-gram board.

My motivation for trying this is that it would provide an easily reversible way to change the actuation/rebound forces on a Topre board. For example, at present EK has some 45-gram RF 87u boards in stock, but the 55-gram boards are out of stock until November. I would prefer not to wait, and I am also not sure if I would prefer a 55-gram over a 45-gram board.

However, this method of modifying a Topre switch must be too easy to be true, and I suppose the characteristics of an auxiliary spring modded board would not be the same as actually changing the rubber domes.

Nevertheless, if this seems like an idea worth trying, does anyone know where I could find 5-10 cN springs that would fit Topre stems? If such springs are not readily available, where could I have some made in small lots for a reasonable price? I would only need enough for one to a few keyboards.

Thanks for any insights and suggestions you might have.

Interesting idea. I like the look of those springs, especially on the all white HHKB:

As for the feel, you're right to wonder if they have a different effect than the corresponding grade of dome. My intuition says a 45g dome + 10g spring wouldn't feel as tactile as a 55g dome, even if it is just as heavy. It's where on the stroke that the weight kicks in that counts. I assume springs help dampen bottoming out a bit but don't add much up at the top.

Still a worthy experiment, however. I'd try it.

Thanks for your insight on this, Mu; your intuition looks correct to me, but I agree it would still be worth trying, especially given the easy reversibility of the mod.

However, any idea where I could get suitable springs or have some made at reasonable cost?

If I knew, I'd say. Your one spring fits every switch and cap, does it? How about measuring it up and doing a search. I imagine they're standard parts.

Muirium wrote:If I knew, I'd say. Your one spring fits every switch and cap, does it? How about measuring it up and doing a search. I imagine they're standard parts.

I've seen web sites that have spring calculators. You provide parameters such as gauge of wire, composition of wire, number of turns, and inner/outer diameter, and it calculates the spring constant and gives a price. However, I think these outfits tend to deal in rather large lots, such as multiples of 1000 or so springs.

I'll also do some measurements and do a search to see if I might turn up a standard-issue spring somewhere. I'll also verify that the spring from the spacebar fits all the keys on the board. It would also be a good idea to check standardization of Topre switches across different makes of boards; i.e., that a 45-gram Topre in an FC660C has the same stem diameter as a 45-gram Topre in a RF 87u. I should think this would be the case, but stranger things have happened.

This is one of the many times when I wish a had a Replicator. Tea, Earl Grey, hot; and a side-order of 87 springs, compression, Topre outside stem, 5 cN.

I think just solving alchemy would have a pretty interesting effect on world economics.

Personally I'd go for a transporter over a replicator.

I did take that spring out of my Realforce, I think, when I found the space bar to be rattly. I couldn't work out what it was supposed to achieve, and I put it back in.

I'd take a replicator, and replicate a transporter (among other things). Just saying. Your turn.

You can't replicate things that don't exist — that would put a whole new spin on human existence if a replicator was capable of inventing anything you want and altering spacetime in order to ensure that it works. That might solve a lot of the paradoxes I wrestle with.

It would exist because it's the same tech. Simplified, if it was file technology, it would be like the difference between mv and cp.

Daniel Beardsmore wrote:You can't replicate things that don't exist — that would put a whole new spin on human existence if a replicator was capable of inventing anything you want and altering spacetime in order to ensure that it works. That might solve a lot of the paradoxes I wrestle with.

But if a replicator also doesn't exist, does that solve the problem? Oh, my! Paradoxes within paradoxes! Just the sort of thing I love.

All seriousness aside, as Steve Allen was fond of saying, what about my Topre springs?

Hmm, I never felt this nerdy in my life.

We should go back to discussing manly keyboards, such as those from IBM.

webwit wrote:Hmm, I never felt this nerdy in my life.

We should go back to discussing manly keyboards, such as those from IBM.

Yes. I'm back to typing on my IBM SSK until I can put more muscle into my FC660C.

When I can find the time, I will be measuring the spacebar spring in the FC660C and running the specs through an online spring calculator to see what it might cost for a special order.

I don't know what the exact weight of the springs are, but these kind of springs could be sourced from some old BTC foam and foils. You would certainly get enough springs from one of those as they are under every keycap.
Perhaps try to find one that is in fair condition with doubleshots. Then you could sell the keycaps to someone that would want them for their MX and get the springs for free.

IvanIvanovich wrote:I don't know what the exact weight of the springs are, but these kind of springs could be sourced from some old BTC foam and foils. You would certainly get enough springs from one of those as they are under every keycap.
Perhaps try to find one that is in fair condition with doubleshots. Then you could sell the keycaps to someone that would want them for their MX and get the springs for free.

Thanks for the tip! I had not been aware of BTC keyboards before. Looks like the spring is mainly for rebound of the key, so it might be light enough. According to EK, the extra spring on the spacebar is very light -- about 5 cN. In any case, I will do some exploring on eBay for BTC keyboards with foam and foil switches and then test out the springs.

Are there particular BTC models I should be looking for?

Edit: Found a BTC 5339 ISO model on eBay for 30 USD shipped. Looks like one of the models with foam/foil switches and return springs, so I bought it. I'll try out the springs and post the results.

For BTC foam and foil, that spring under the keycap is the only spring you get. It will be fairly stiff, accordingly.

Daniel Beardsmore wrote:For BTC foam and foil, that spring under the keycap is the only spring you get. It will be fairly stiff, accordingly.

Hmm, looks like the springs will likely be much too heavy for my current purpose. Live and learn.

I don't recall them being particularly stiff, which is why I thought it might be suitable. If they are a little stiff, perhaps it still might be satisfactory, 75g Topre?

IvanIvanovich wrote:I don't recall them being particularly stiff, which is why I thought it might be suitable. If they are a little stiff, perhaps it still might be satisfactory, 75g Topre?

The BTC board is on its way and should arrive by the end of this week or early next week, so I intend to test the springs. Provided that the springs fit the stems, it will be fun to see just how hefty the modded Topres will be.

rjrich wrote:

IvanIvanovich wrote:I don't recall them being particularly stiff, which is why I thought it might be suitable. If they are a little stiff, perhaps it still might be satisfactory, 75g Topre?

The BTC board is on its way and should arrive by the end of this week or early next week, so I intend to test the springs. Provided that the springs fit the stems, it will be fun to see just how hefty the modded Topres will be.

Well, the BTC board arrived and it was a disappointment. I must have had the wrong model number. There were no metal springs. Instead, there were silicone rubber cylinders morphing into square pyramidal bases. I tried one with a Topre stem, but the size, geometry, and compression strength were not compatible. I think my next step will consist of doing spring measurements and using one of the spring calculator web sites to see if custom springs could be ordered for a reasonable price.

The more I read about them in the Wiki, the more chaotic most keyboards seem to be. Manufacturers seemed to screw around with changes to basic components at a whim with such enthusiasm that perhaps they imagined someday in the future, someone might try to figure them out and lose their mind! (Sorry Daniel…) Pretty much everyone was at it. From IBM's buckling spring free Model Ms to Apple's Alps-less Extended Keyboard IIs. Argh!

So it's not a total surprise this donor board crapped out. I'm tempted to ask how its keys feel, but I don't want to do anything to start you on the opposite challenge to that you've already completed: what is the ultimate bad keyboard!?

Muirium wrote:The more I read about them in the Wiki, the more chaotic most keyboards seem to be. Manufacturers seemed to screw around with changes to basic components at a whim with such enthusiasm that perhaps they imagined someday in the future, someone might try to figure them out and lose their mind! (Sorry Daniel…) Pretty much everyone was at it. From IBM's buckling spring free Model Ms to Apple's Alps-less Extended Keyboard IIs. Argh!

So it's not a total surprise this donor board crapped out. I'm tempted to ask how its keys feel, but I don't want to do anything to start you on the opposite challenge to that you've already completed: what is the ultimate bad keyboard!?

Yes, I agree. Thanks for the consolation. For me, one of the worst keyboards I have tried to type on was a full-size Apple keyboard that had a clear plastic shell and mushy white keys that had a tendency to stick. I think this was one of the variants of the Apple Pro keyboard, but I am not certain.

Sounds just like it. There were a few variations on the theme (black keys, white keys; curved back, slab back) but they were all the stuff of profound keyboarding evil. Just think of the cruelty in letting people see what gets stuck inside! Genius.

The modern one's a huge improvement. It ain't no mech, but it's much more Apple than its predecessor, which wasn't even slim or metal…

Muirium wrote:Sounds just like it. There were a few variations on the theme (black keys, white keys; curved back, slab back) but they were all the stuff of profound keyboarding evil. Just think of the cruelty in letting people see what gets stuck inside! Genius.

The modern one's a huge improvement. It ain't no mech, but it's much more Apple than its predecessor, which wasn't even slim or metal…

Muirium, you are a genius, especially when it comes to finding just the right image to illustrate your point.

Yes, the current Mac keyboards, although not true mechs, do look great. Perhaps they would even be fine for typing if the typist were to have his fingers outfitted with shock-absorbing springs.

The layout of the Mac wireless is also excellent; it would be good if it came in a corded version or if the current Mac Pro could improve its wireless connectivity -- I have a colleague who was having trouble getting his Mac Pro to connect to the wireless keyboard. He finally gave up and bought a Matias Mini Tactile Pro.

As for me, I am continuing to enjoy my new HHKB Pro 2. Yesterday the white and light gray keycaps arrived, and I installed them. I like the contrast of the light-colored keycaps against the black case. Moreover, now that the legends are visible, even in dim light, I can navigate the Fn layer even better. Perhaps if I can master the Fn layer at the level of touch typing, I can get a white model for the extra set of black on dark charcoal gray keycaps (not a true extravagance, as I need two keyboards at work and one at home, plus extras when troubleshooting individual computers requiring direct connections to keyboards rather than using the KM switch). Hmm, this sounds like rationalizing my addiction....

Put your lesser boards on sale and see what the results buy in HHKB money. There's always time to hoard your favourite models, especially when they're still in production!

The old Mac Pro has crummy Bluetooth reception from what I've heard. My old G5 (the age of my Macs gives away why I don't have all the high end keyboards that I want…) is okay at Bluetooth using its little Apple-supplied dongle on the back, but the laptops are far better. My gripe with Apple's peripherals on Bluetooth isn't their signal strength but their tediously small limit of stored pairings. Both my Magic Mouse and Aluminium Bluetooth Keyboard max out at four hosts, and adding any more means losing others. Ugh! Naturally I found this out when adding a fifth device and gradually thinking I was losing my mind.

Muirium wrote:...
The modern one's a huge improvement. It ain't no mech, but it's much more Apple than its predecessor, which wasn't even slim or metal…

Yes, you know the old saying, you can never be too thin or too metallic....

Muirium wrote: ↑Interesting idea. I like the look of those springs, especially on the all white HHKB:

Spoiler:

As for the feel, you're right to wonder if they have a different effect than the corresponding grade of dome. My intuition says a 45g dome + 10g spring wouldn't feel as tactile as a 55g dome, even if it is just as heavy. It's where on the stroke that the weight kicks in that counts. I assume springs help dampen bottoming out a bit but don't add much up at the top.

Still a worthy experiment, however. I'd try it.

You could try removing the spring from the spacebar and putting it on a different key to see what would happen.

I think having these springs available would be a decent compromise for people who want to increase weight of certain keys without going into the guts and to switch out the rubber membranes (and probably voiding warranty). Probably if you got a 35gm Noppoo EC108 and you want to add springs to the caps-lock so you don't accidentally turn on caps