Author Topic: IBM F122 with "Brand New Model F Keyboards" Flipper/Spring swap vs stock  (Read 3815 times)

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Offline Pretendo

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In March of 2019, I decided to swap out the springs and flippers in my F122 keyboard with those from the "Brand New Model F" project.  I wanted to keep my existing F122 key layout, but liked the idea of having "brand new keys" under the hood.  I also got an early buyer price on them which made the swap fairly accessible.

Fast forward to this week, and I decided to switch my board back to stock to see if there was any perceptible difference between the old and the new. I did notice differences immediately after that change, but it's been a few years now. The new assemblies had been broken in for awhile, so it seemed as fair a time to make the comparison as any.

Here are my results, and a very quick opinion on the old vs new setup.

Caveats: the original spring assemblies are 40 years old. The new ones are three years old.  The old assemblies were also starting to rust at the tips of the springs and were treated in vinegar to remove this rust.  I'm not sure what differences age or rust removal brings on, or how much of the difference could be attributed to the heavy service life my keyboard likely had. 

I also did not buy new barrels to go with the springs and flippers, so there may have been some slight differences if I'd also replaced these.  I assume that the springs and flippers for the new board were specifically designed with the new barrels in mind, but everything was designed to be drop-in so I didn't bother buying these. They were also too expensive for a full board replacement.  I assume most people who would be attempting this swap would probably go the same route that I did and keep the old barrels.

Feel: The original springs and flippers feel like they have slightly heavier key action, but also feel slightly more precise.  It's as if the slight extra force is causing the pivot point on the hammer to snap with just a tiny bit more precision after actuation. The weight difference is noticeable right off the bat immediately after the switch but fades after a few minutes. The precision difference is even closer, but in contrast only becomes noticeable after typing for awhile.

I give the very slight edge to the original springs, but it's subjective.  It's picking the tiniest of nits, and it's amazing how close they really are. Those who prefer a slightly lighter switch would probably prefer the new flippers, but the difference is small enough where nobody would pick it out without demoing them back to back.

Sound: The new Model F springs are a tiny bit more resonant. They seem to ping at the same frequency, but to my ears the new ones "sing" just a tiny bit louder.  There's not much else to say that this, because they're otherwise identical sounding.

Again, I have to call this subjective, but I ever so slightly prefer the original.  The noise of the F has always been one of its pain points for me, but other people may simply not notice or prefer the slightly different sound.

Construction: Both look to be identical in build quality. Aside from some very minor manufacturing differences, they look the same.  One does not look cheaper or worse built than the other, and you'd have to be trained to know which was which.

Here, it's a tie.


Overall, I would say that if you have the original springs and there's nothing wrong with them, there's not much reason to switch to the new ones.  In reality, even a board that's suffered heavy use like mine still has 99% of its service life ahead of it, so all Model F's are still "new" in that way. I don't think most people would gain anything by "rejuvenating" their key switches in this way, unless they were damaged or the board was worn out to an absurd degree.

The only exception is if you find the Model F just a tiny bit too heavy in its key force, and are willing to trade a fraction of precision for that.  This minute difference would have to bother you so much that it was the deal breaker which caused you to shove your Model F into the hall closet, and a perceived 5g difference in actuation force would save the whole experience for you. Unless it's that level of a pressing concern, the cost of the replacement flippers (they are more expensive now) along with the effort of installing them is probably not worth it.

Likewise, if you have a brand new Model F and wanted to gut your old keyboard and put the original springs in for some reason, I'd advise against it... but I feel like the number of people considering this path are far fewer than those considering what I did.

As far as single key repairs or adding new keys go, the new F flippers would be very suitable, as the differences are subtle. You'd probably want to be mindful of which keys you switched, and maybe select a lesser used key to put the different flipper on. Even if you didn't I doubt it would be distracting unless you were looking for it. If you own a Model F and are considering adding keys for a layout change or just want backup assurance, I wouldn't hesitate to buy a few assemblies for the side in case you need to do a repair.
IBM Model F-122 6110347 -- September 13th, 1984
IBM Model M 1391404 -- April 14th, 1988
Rosewill RK-9000