Mechanical switch specification range and those pesky plus and minus signs
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So you finally decided Build your own mechanical keyboard And is looking for the perfect mechanical switch for your picky fingers. Or, you may be looking for a pre-made keyboard and carefully read the available switch options. The specification sheet seems simple: it includes a measurement of the total stroke of the switch, a measurement of the pre-stroke distance, and a measurement of the force required to activate the switch. But what is this? Since taking math class, you have never encountered the “±” symbol.Suddenly, you realize that the pre-travel of the switch is not just 2.2 mm, but range The value of “2.2 ± 0.6mm”.
Although many people in the industry, from keyboard enthusiasts to keyboard and switch manufacturers and partners, simplify switch specifications to specific numbers, if you look closely, you will find that many switch specifications are actually written to cover a range of measurements .
take Cherry MX Blue change. If you know the switch well, you might think you know that the total stroke of the MX Blues is exactly 4 mm, the pre-stroke is 2.2 mm, and the driving force is 60 grams.However, Cherry’s MX Blues official data sheet [PDF] Tells a more detailed story.
This table points to a switch with a pre-stroke distance of “2.2 ± 0.6mm”. This literally means that the switch can move 1.6-2.8 mm before being activated. However, most people will tell you and expect the MX Blue switch to activate at 2.2 mm-no more, no less.
It doesn’t just stop before traveling. Continuing our MX Blue example, the spec sheet says that it needs 50 ± 15 centinewtons (cN) to start. This is a force of 35-65 cN. In terms of full stroke, the specification of Cherry MX Blue is “4-0.5mm”. This time the range is narrower-4-4.5mm-but it is still worth noting.
Of course, Cherry is not the only player here. You can find these offensive “±” symbols in the switch manufacturer’s specification sheet. E.g, Kailh x NovelKeys Box Cream The specifications of the switch are 3.7-4.3mm stroke, 1.5-2.5mm pre-stroke and 35-55 grams (g) driving force.
This is not something that only enthusiasts who have a deep understanding of the PDF of the data sheet will discover. Even people who buy pre-made keyboards may find switches with specification tolerances, as they say. E.g, Product page in order to Keychron K3 When describing the provided thin Gatreron switch, the ± symbol is highlighted.
The tolerances of mechanical switch specifications give switch manufacturers leeway in the very precise performance of their miniature keyboard assemblies. When we say very precise, we are serious; these are the nuances we are talking about.
“That is to say, every switch manufacturer will make their products switch to the exact specification as much as possible. But they cannot guarantee that all switches they manufacture have exactly the same force and travel distance, so they are The specifications set a safety margin,” Paul Tan, chief operating officer of Keychron, told techy’s points.
But considering that the specification sheet usually provides hard data (imagine it, if the CPU says it has 2 ± CPU core! ), even for keyboard lovers, this can be confusing.
“Ordinary consumers will be very confused when they see this. To be honest, for ordinary consumers, this may not affect their purchases at all,” Keyboard mud Alexander “Alexotos” Medeot Tell techy’s hardware. “This is for those who really go deep and look for something very specific. I would say fanatics who even surpassed you.”
Switch manufacturers seem to be reluctant to commit to a certain specification; however, Michael Sicker, owner of NovelKeys, which sells and manufactures its own keyboards and switches, says that tolerances are more of a switch requirement manufacturer, Instead of switching Brand Like it myself and cherries.
Sickler also attributed the need for tolerances to cost and time.
“When you start to really hone the tolerances of these switches, the cost of manufacturing molds will be higher because you get into a range that might be considered NASA-level tolerances,” Sickler told techy’s points.
If you take transparency seriously and set your expectations correctly, you may be a little angry now. Going back to the example of MX Blue, if we look at its specification sheet literally, it means that a bag of MX Blue switches may have some samples with 1.6 mm pre-travel, 3.5 mm and 35 grams of force, while other samples have They are 2.8 mm, 4 mm, and 65 grams, and any specifications in between. When what you might want is 2 mm, 4 mm, and 50 grams.
One of the biggest tolerances we have seen is Cherry MX Silent Blacks, Can have a driving force of 60 ± 20cN [PDF], Allowing a potential range of 40-80cN. The good news is that when you buy a pack of MX Silent Black, you are most likely to get a switch with the exact specifications of 60cN force. If not, the difference may be so small that even switch enthusiasts will not notice.
Alexotos has manufactured more than 350 keyboards and owns more than 70. He said that when it comes to specifications such as pre-stroke, stroke and driving force, any difference between the same switch is so small that most people can’t tell. He pointed out that the tolerance for Cherry MX Blues was “very different”, but said he had never noticed this personally.
“Unless you sit there and test each switch carefully. It’s hard to tell the difference between a lot of these things…” Alexothos said. “Again, I think that for the average consumer, these specifications are listed there just to prevent someone from measuring something, but this is not something I have noticed, or have to worry about personally.”
Sickler of NovelKeys agreed.
“For most people, the actual range of the switch is almost always imperceptible, especially when you type very quickly,” he said.
According to Tan of Keychron, despite the large switch tolerances, to find a switch, you will actually encounter samples that measure within all the extreme ranges listed in the spec sheet.
“We are not sure when the industry will change their specification sheets, but switches usually don’t have this range,” Tan said.
In fact, when it comes to the differences between the same switch types, there may be more important things to worry about. Alexotos pointed out that the difference in valve stem swing caused by the mold used is more common than the difference in stroke and driving force.
At the same time, Sickler pointed out the batch of springs that showed the biggest difference, but pointed out that this would not really affect the typing experience.
“I mostly only see a difference of about 5g, and it is almost impossible to detect, especially when typing,” he said.
So should you worry about getting a bunch of the same switches with very different feels? Probably not. Professionals like Alexotos won’t.
“I will watch 2.2[mm] And read 2.2[mm],” he said. “I know there are differences, but the differences are accompanied by literally…everything: plastic, stem, nicks, and things in plastic. A lot of things in the switch may be different, but I see it as what the vendor lists. ”
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