I bought a Cherry keyboard on eBay from the auction being discussed
here. One nice thing about this keyboard, if you're looking to harvest key switches, is it has many extra keys. I counted 120 total.
For this mod I only set out to replace the main typing switches on the Filco. I didn't want to replace all the keys because I have a second keyboard I will convert to Cherry clears, and need enough keys to go around. So you can see in the first picture which keys are still Cherry browns.
The donor keyboard was easy to take apart and easy to get the keys off of. There are 4 solder points per key, but they melt easy. The Filco was harder to take apart. Also the keys were harder to remove from the Filco, because of the metal plate and because the solder didn't melt as easily. I found it worked best to periodically re-tin the soldering iron as I went.
The least destructive route would have required me to open all the key switches and convert the browns into clears. This is because the clears have a diode inside the key, resulting in the 2 extra leads per key, and they also have plastic legs that go through the circuit board. The Filco only has 2 circuit board holes per key (its diodes are surface mount, and its keys don't use plastic legs). To save time and effort, I took the destructive route of clipping off the diode leads and plastic legs, and so avoided having to open each and every key (browns and clears).
Putting the Filco back together was easy. It was a bit tricky getting switches in and out of the positions that have stabilizer bars, as I didn't remove the bars out of fear of breakage.
So far, I really like the clears. I've only tried Cherry blacks, browns and clears (also there's a gray switch under the space bar if you count that). I also have a variable pressure Topre. In my opinion, the browns and variable Topre are far too light, resulting in many unwanted, incidental key presses. For a while I was used to the blacks, though now after typing on the Topre for a long time, they seem heavy. Clears fall right in the middle, like a cross between browns and blacks. It's harder to compare the Topre since it's a rubber dome (though not your ordinary RD) and has a much smoother pressure curve.
I briefly tried brown switches with clear springs, and vice versa, but just for a couple keys (not the whole board). Brown switch with clear spring seems to just stiffen the brown key's feel and lessen the tactile-ness. Clear switch with brown spring felt like an extra-tactile brown. I conclude that a big part of what makes a clear a clear is the higher spring strength. The increased tactile bump is secondary, though also important.
The mod was done in one evening. It took about 45 minutes to remove the keys from either keyboard (donor keyboard was easier but had many more keys and solder points). Putting it all back together took about 20 minutes, mostly spent fighting the stabilizer bars. Re-soldering was quick in around 10 minutes or so. All combined I think one could do this in under 2 hours. These times include efficiency increases as your technique improves.
Edit: It may take closer to 3 hours for the mod. I left out time required for minor steps such as: taking apart the Filco, clipping legs off all the clear switches, and testing the keyboard (before putting the case back together!) to ensure all keys are working.
UpdateAfter a few days with the Cherry clears, I noticed they felt a bit too heavy for me, especially on the outer perimeter keys. So I experimented with different key configurations to improve the feel.
At the start of this mod, I planned to convert a second keyboard to Cherry clears. That board is a Deck 82 with Cherry blacks. I tried installing black springs in the clear switches, really liked the lighter feel, and knew I had to go back to the drawing board with the Filco.
It may not seem obvious that black springs are weaker than clear springs, after all, black switches require higher activation force than clears (60 cN vs. 55 cN). I think this can be explained by looking at the tail end of the force graphs. The black spring actually bottoms out at about 80 cN, whereas the clear spring bottoms out close to 100 cN. It helps to look at the force graphs overlaid:
By combining the black spring with the clear stem, the result is a key switch that's easier to press than a Cherry clear, and more tactile than a Cherry brown. It finds a really nice sweet spot in between, and is my new favorite key switch! Since it's a cross between clears and browns, I think the name "ergo clear" fits well.
The plan was to mod the Filco using these ergo clear switches for everything except the left and right sides of the main typing area. For the side keys, I still prefer browns (although full-brown keyboards aren't for me personally). Here's the layout I implemented. All gray keys got the ergo clear switch (except the space bar, which is an 80 cN Light Grey switch), and all brown keys got brown switches:
Opening all the cherry keys to perform this mod quickly became very frustrating. I ended up making a key opener tool that made the process much, much better. Just stick some tacks through a piece of foam, and wrap the foam with tape. Using the tool once on each side of a Cherry switch, the keys pry open easily.
Since I was going through the trouble opening all these keys, I decided to go ahead and lube them. I used this
spray PTFE dry lube, bought at Home Depot. I just sprayed it into a bowl to get a liquid, then dipped the springs and key stems (being careful not to lube the outside/exposed part of the stem). So far the lube has helped dampen the scratchy key feel that tactile Cherrys have to varying degrees.
Lastly, I changed the caps-lock LED to green before putting everything back together.
Overall this was a pretty time-consuming weekend project, and I'm very happy with the results. The keyboard has a great feel that is satisfying and definitely unique. I'm not sure how others would like it, since it seems very much tailored to personal preferences. I'm still looking to finish modding the Deck keyboard, but now I need a source of black springs to make more modded clears! :)
