Single unit thumb keys - a bad idea, really?

[design]

I feel that there is a major issue with using a low-width (1 or 1.5 unit) key for Space that I haven't seen discussed anywhere. It is an issue with most of the more advanced mech ergo boards on the market in my opinion. It can be visualized by looking at the wear patterns of spacebars (see the thread image) on much-used keyboards - the area where the key is usually pressed on standard keyboards is much wider than 1 unit. Therefore, in my opinion, the ideal width of a spacbar / space key is 2 units, extending inwards from the thumb's natural resting position with the other fingers on the home keys. This should at least be true for the thumb that enters Space but probably also for the other side if planning to use the main secondary thumb key as a modifier, like Shift.

Spacebar wear pattern example

Why? Well, when you hit a key with your index finger on the center column (e. g. 'h' or 'n' on QWERTY) followed by space on a keyboard with a 1 unit space key, you will have to return your hand to the home position before being able to hit space, which will slow you down. If you're using QWERTY, frequent words that end in 'n', like 'in', 'on' etc. will become annoying once you switch to such a thumb cluster board.

To illustrate (for people using their right thumb only for space): On a standard keyboard, type the word 'am', paying close attention to the location where you touch the spacebar with your thumb after the 'm'. Then do the same thing typing the word 'an'. Compare the exact spot where your thumb presses space this time. For me, there is a definite shift in thumb press position.

Unless you are going to / have switched to a layout that de-emphasizes the center columns, this might become a PITA. I own a Keyboardio Model 100, for example, and what I am describing is definitely an issue for me. I personally feel that one wide thumb key and one additional key outwards (i. e. in the direction of the pinky) from the center for each thumb is the best solution - can't really see myself using more than those thumb two keys on each side while typing.

Of course, the same effect occurs in the other direction when you use keys outwards from the pinky's home column. However, to avoid this issue, you'd have to have an even larger space key that extends pinky-wards, too, and you'd be stuck with only one easily accessible key per thumb so in that regard, I'd prefer having the additional thumb key. With regard to the relatively frequently used center columns, though, a narrow thumb key is a hard sell for me, at least for QWERTY users. I guess it's all a question of preference - if some really wants a lot of thumb keys or uses a center-deemphasized layout, they might be willing to sacrifice the comfort / speed advantage of a wider thumb key to make room for an additional key whereas someone focused mostly on writing text on QWERTY should probably reconsider.

As for alleviating this through layout design, I guess it would be best to put letters in the central column that are A) infrequent and B) rarely appear at the ends of words. The worst choice of layout with a narrow thumb key design seems to be one with punctuation (which is almost always followed directly by space) on the central column as, for example, with the Engram layout.

To be honest, I've never really typed much on such keyboards so this comes from a hypothetical / theoretical perspective. Please do contradict me if my theory is at odds with your own experience.

[Edit:] The issue seems to be more inherent to row-staggered boards as the hand has to move further inward for the index to reach the most distant key on the central column.

in ErgoMechKeyboardsby Keybug

69%

8mo

Jon808517

8mo

It’s a non-issue for me. 1U space on the thumb works just fine.

However, that doesn’t mean it’s true for everyone. I think we don’t talk enough about hand shape in ergo mechs. Not everyone’s thumb moves the same way, so that can likely play a big part in how comfortable something is.

I think the wear pattern can be a little misleading as well. I know when I was using a regular space bar, I would swipe at it a lot, which would give the impression that I needed a wider target but after several years with a 1U thumb for space, it hasn’t mattered at all. I had no trouble adjusting.

Like all too many things in this hobby space, you really just don’t know until you try it and a lot of this stuff is personal preference. You’re sure to find a group with similar preferences and you’ll find plenty of other groups that feel the complete opposite. You just have to try it yourself.

thomasbaart

[vendor] (splitkb.com)

8mo

Nice write-up! I don’t have scientific sources on this, but there are a select few examples of (split) keyboards with wider space bars. For example, I recall a few of the (now closed) gboards.ca designs had them. The Redox is another example.

You also see quite a few more designs with a taller thumb key instead of wider.

I prefer 1u myself and don’t consciously experience slowdowns, though I also type with around 100-120wpm most of the time so maybe a noticeable slowdown occurs above my speed, or perhaps I’ve reached my plateau because of it ;)

Thraeg

8mo

Interesting observation. I can't say I agree, though. With a column-staggered board that better fits the length of my fingers, I type keys in the center column by just moving my index finger rather than the entire hand. Hitting space afterward feels exactly the same as when it follows any other key.

I wouldn't want to give up an outer or inner thumb key to make room for a 2u main thumb key, as I make substantial use out of all the keys on each thumb.

AnythingApplied

36-corne | miryoku | zmk

8mo

I've seen some ergo keyboards with wider thumb keys (taller is more common, but not what you're talking about) and I gotta say I'm really not a fan. First, I hardly had any issues adjusting to hitting space with just a single one of my 6 available thumb keys (though I did decide to swap enter and space positions, just because I was getting those backwards too often).

Well, when you hit a key with your index finger on the center column (e. g. 'h' or 'n' on QWERTY) followed by space on a keyboard with a 1 unit space key, you will have to return your hand to the home position before being able to hit space

For the most part, only my index finger moves when this happens. The slight shift in my other fingers is not a 1u movement as they are largely still in their home positions and even if it was a full 1u movement, it wouldn't stop me from pressing both H and space without returning my hand, more of a finger stretch then anything, though it doesn't feel like much of a stretch to me. My ring finger for example is still resting on its home row key.

The main reason why I'm not a fan is because the thumb range for comfortable use is limited. I actually find frequent use of the corne's thumb key closest to the pinky to be a source of pain and so do others. I still use that thumb key, but have mapped it to things I rarely use. With a double wide thumb you either need to sacrifice a thumb key or ask your thumb to move in a larger range of motion, both of which are significant sacrifices for something I don't really see the need for. Before you add a thumb a thumb key closer to the pinky, you should at least read through that article.

I'm not sure I find the wear pattern compelling because you're not being asked to hit a specific spot and with the right key profiles you'll have a edges that naturally keeps your thumb aligned with the center of the key. Its like when I take off my shoes, they don't always end up in the exact spot, but I had some marks on the floor for where to leave my shoes, I'd have no issues leaving them in that same precise position. The bigger issue at play is the feeling of needing to reset your hand position or the feeling of stretching your hand... both of those reasons would be compelling and just is something I don't really experience.

All that being said, the thing that makes a keyboard ergonomic is being good and comfortable for your hands and your usage. If you think that your hands would be more comfortable with a larger thumb target, especially after you've had some time to experience thumb clusters for yourself on your Keyboardio, then there is probably good reason for that belief. I might encourage you though to not go to a full 2u even if that is the size of your usage. That may require reigning in your thumbs natural desire to wander a little in order to avoid having keys so far outside the thumbs comfortable range of motion.

Keybug

8mo

Interesting! While I don't move my thumb an entire unit inwards when hitting a key on the inner column with the index finger, I'd say the thumb moves around 0.6 unit every time without fail.

If your thumb remains in place while you are doing the same thing, wouldn't that have the same kind of effect as moving the thumb palm-wards to press an outer (i. e. pinky-ward) thumb key, which you have (righly, I'm sure) made out to be an ergonomics issue? In both cases, a kind of pinching movement of the thumb occurs, doesn't it? Though maybe with index on center column it's not as pronouced as when pressing that outer thumb key.

AnythingApplied

36-corne | miryoku | zmk

8mo

If your thumb remains in place while you are doing the same thing, wouldn't that have the same kind of effect as moving the thumb palm-wards to press an outer (i. e. pinky-ward) thumb key, which you have (righly, I'm sure) made out to be an ergonomics issue?

When I hit the H key, my index finger moves away from the rest of the hand. When I hit H, it causes the gap between my index finger and the rest of my hand to increase, so its not like other my fingers are moving a full 1u. This gap covers most, if not all, of the 1u distance rather than my hand actually moving. So, even if there was some natural movement there for the thumb to want to come with the index finger, its only part of the 1u, like 0.25u. So yes, maybe I'm stretching my thumb an additional 0.25 towards my pinky to maintain its position on space... but ultimately the key I find gives me a little grief if I use it too frequently is a full 1u (if not slightly more due to each thumb key being angle slightly differently so they aren't right against each other) towards the pinky (my space is the middle of the 3 corne keys) and that only becomes a problem if I use it too frequently. And just because a key can cause some pain if used too frequently doesn't mean I should try to avoid it entirely because its not too unreasonable to assume that that would be true of ALL the keys on the keyboard that there is some threshhold of usage that starts to cause pain. Its just about not over taxing any one finger and my thumbs can absolutely handle some use of that thumb key most towards the pinky.

Weirwynn

Custom Mid-Size Split w/ Canary Layout

8mo

No. You can certainly say that you prefer it, but as a general rule, no. Inaccuracy in pressing a large button does not translate into needing a large button.

Keybug

8mo

I don't think inaccuracy is what it is. It seems to depend on typing style. If I had two one unit thumb keys, both set to send space, then after pressing a key on the center column with my index, my right thumb would definitely prefer hitting the key to the left of the 'home' thumb key as I would have moved my whole hand plus thumb left by more than half a unit. In that instance, using this key for space rather than the home key would make me type type faster (pressing space immediately rather than having to move back a fraction first), especially when the next keypress is on the other hand.

vinegarwarlock

8mo

2u needs a stabilizer, and I don't know of any manufacturer who sells them individually, so you would be increasing cost and space required for the build. Also, 1u keys are easy to find, 2u options are more limited depending on kit. For example when I bought KAM caps I could do my whole build with just the alphas kit. An extra 20 bucks minimum would be required to get some 2u keys: if I just used a 1u where a 2u and stabs should be it would definitely be harder to target.

mkleehammer

8mo

I have multiple Plancks and similar w/ 2U spacebars and no stabilizers I do agree they are harder to find, but worth it to me

YellowAfterlife

sofle choc, redox lp

8mo

To be honest, I've never really typed much on such keyboards so this comes from a hypothetical / theoretical perspective

You can print some 1:1 scale layouts on paper using splitkb's compare tool and see how your hands lay upon them - long story short, column-staggered keyboards have wildly varying thumb key placements, and you can generally find something that suits you - so that your thumb sits comfortably on one or between a couple keys.

sunirgerep

8mo

The effect is probably also influenced by key spacing. If you use choc spacing, your keys are closer together anyway, resulting in less reaching motions for keys further out, therefore the way back will also be shorter and result in less deviation. Naturally finger length/hand size will have a similar influence.

My personal layout has 4 1u keys for each thumb and I never had any problems reaching them, but then I spend 15mins placing the thumb cluster exactly where my thumbs fall naturally. If your keyboard is just a general fit to your hand, that experience might differ. I would trade less wide, harder to hit 1u keys for more, easily reachable thumb keys any day, but that is another debate.

moonflower_C16H17N3O

Piantor Pro - Sunset Switches

8mo

On my old keyboards, there would be a large streak where my thumb. Instead of just pressing my thumb directly down, I'd curl it. It would drag over the bar and actuate the switch. Now that I am using split ergo keyboards, it"s more like I am pushing my thumb to the left to push the key.

So, it has changed, but I don't feel like I'm in any discomfort because of it.

Thorlian

8mo

I've been using a planck with single unit thumb keys for years, never had any issue. 1u keys allow me to have 2 thumb keys per hand in a compact form factor. I can't imagine going back to a large spacebar

Major_Toe_6041

8mo

I have a lily58, my space bar is technically 1.5u, however the angle makes it a 1u as far as my thumb is concerned. I must say I can’t agree with your statement, as good as it is, I much prefer it this way. I suppose it just depends on where your thumb naturally rests, and if you are typing ‘correctly’ (if you aren’t, your hands are jumping about so your thumb is moving). In my experience, 1u hasn’t at all affected my typing. However as another user said, it’ll be different for everyone. Each to their own, I suppose.

Keybug

8mo

I'd still maintain that replacing the large spacebar on a standard keyboard with a one unit key will result both in reduced typing speed (if not very significantly so) and comfort, especially if there were other keys beside it that could get in the way. Should make for an interesting experiment...

demibyte

8mo

On a standard qwerty board I'd believe it. On an ergo mech board it's really going to depend how well the ergonomics of the board match the ergonomics of your hand. If feel like if you have a good match you shouldn't really have an issue,I've custom fit my board to my ergonomics and I certainly don't. I use a 1.25u for home thumb key but even that is more about homing than the need for width.

I suppose everyone is different though an if you think a wider thumb key will be more comfortable for you than I won't nay say it.

cyanophage

8mo

Keycaps made of good materials don't wear out like that

Keybug

8mo

True, but I'm more concerned with ergonomics / typing speed.

ProgressiveNoise

8mo

I've failed to emulate it, my thumbs are rock-solid in the same position even on my laptop. With my ergo, I rely on my thumbs more than on "J" and "F" for relative positioning of my palms. Wide caps would be a disaster in my case.

yurikhan

8mo

when you hit a key with your index finger on the center column (e. g. 'h' or 'n' on QWERTY) followed by space

Standard typing technique (as translated to split keyboards with thumb clusters) teaches that you should be using the other hand’s space key. So, right hand index types the n, left hand thumb types the space.

That said, I have exactly zero issues keeping my thumb at its home position when typing inner column letters.

Also, if you are in any way concerned with typing speed and/or comfort, you migrate off QWERTY as the first step, or at the same time with ditching row stagger.

(All subject to personal preference, of course.)

Keybug

8mo

Standard typing technique (as translated to split keyboards with thumb clusters) teaches that you should be using the other hand’s space key. So, right hand index types the

n

, left hand thumb types the space.

Not sure what standard you are referring to. If I understand you correctly, that would mean assigning space to the main thumb key on both hands. I very much doubt more than 0.x% of users would be prepared to do that. I've also never heard it advised to operate space by alternating thumbs - too much cognitive load IMHO.

By the way, I think there is now a pretty general consensus that alternative layouts have a negligible effect on typing speed. Comfort is another matter, of course, you're certainly right there.

To me, it still seems unnatural to have to 'lock' your thumb in a space of one unit while typing fast - I'd see it as an ergonomic stressor, though maybe a minor one. As has been suggested here, moving beyond row stagger will alleviate the issue a good deal (more thumb movement will happen with index tapping Y than when tapping N on row-staggered QWERTY). I'll try to settle on 1.5 unit wide main thumb keys and maybe a slightly higher keycap than on the surrounding thumb keys should I ever move past row stagger. (Am currently on an Alice form factor.)

yurikhan

8mo

The standard technique I’m referring to assumes QWERTY and a wide space bar. I’m just extending it to split keyboards, and yes, I imagine it involves two space keys.

I happen to use primarily the right hand thumb for space, but I retain my left space key for page scrolling in browsers when my right hand is on the mouse. Not sure about your 0.x% estimation.

Keybug

7mo

Some cases in point ...