Clear Resin Casting Replicates Old Acrylic For Selectric Repair

IBM Selectric typewriters have a lot of unique parts that can be tricky to source, but one we didn’t think of was the clear acrylic(?) dust covers, that are apparently very hard to find in good shape. [Eric Strebel] has a few Selectrics that all have issues with these parts. While you could come close to recreating this piece with acrylic sheeting carefully bent to match the original shape, [Eric] has a different hammer to try in a new video: replicating it with a resin casting.

He uses de-gassed tin-cure silicone to create a mold for the original, with a bit of 3D printed PLA and foam board to hold the silicone to create the mold. That’s done in two steps to create a two-part mold, which is separated and cleaned before the resin goes in. The original part is actually a smoky plastic, rather than fully clear, but [Eric] is able to match it perfectly using a colourant in his clear ̶e̶p̶o̶x̶y̶ polyurethane resin. The resin is put into the mold with a simple gravity pour, though he does have a vibrator on it to help it flow. Curing is done under heat and pressure– 60 PSI. The results are amazing; once he adds a touch of paint to match the black finish on one face of the original, it’s very difficult to tell [Eric]’s casting from his master piece, except that the cast replicas are in better shape.

This particular part works very well for casting and not much else. While you could match the large curve by heat-bending a piece of smoky acrylic, there are lips along the edges of the part that would be tricky to reproduce. [Eric] also needed several, for his multiple typewriters, and this method is very efficient at producing multiple units since the mold is reusable.

While you might not have an IBM Selectric that needs a dust cover, this technique is equally applicable to all sorts of clear shapes. If you’re new to resin casting, we have a handy guide to replicating plastic parts to get you started in this kind of work. It’s not just large parts that can be replicated: you can even copy phonograph records, such is the fidelity of resin casting.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Schreibmaschine

Choc switches on a ThumbsUp! v8 keyboard with IBM Selectric typewriter keycaps, thanks to some 3D-printed adapters.
Image by [Sasha K.] via reddit
Remember that lovely Hacktric centerfold from a couple Keebins ago with the Selectric keycaps? Yeah you do. Well, so does [Sasha K.], who saw the original reddit post and got inspired. [Sasha K.] has more than one IBM Selectric lying around, which is a nice problem to have, and decided to strip one of its keycaps and get to experimenting.

The result is a nice adapter that allows them to be used with Kailh chocs — you can find the file on Thingiverse, and check out the video after the break to see how they sound on a set of clicky white chocs.

Those white chocs are attached to a ThumbsUp! v8 keyboard, a line that [Sasha K.] designed. His daily driver boards are on v9 and v10, but the caps were getting jammed up because of the spacing on those. So instead, he used v8 which has Cherry MX spacing but also supports chocs.

As you can see, there is not much to the adapter, which essentially plugs the Selectric keycap’s slot and splits the force into the electrical outlet-style pair of holes that chocs bear This feels like an easier problem to solve than making an adapter for MX-style switches. What do you think?

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Cutting Board Keyboard

Doesn’t this look fantastic? Hard to believe it, but the base of this keyboard began life as a cutting board, and there’s a gallery to prove it. This is actually [androidbrick]’s second foray into this type of upcycling.

This time, [androidbrick] used a FiiO KB3 and replaced the bottom half of the plastic shell with a hand-routed kitchen cutting board. The battery has been disabled and it works only in wired mode, which is fine with me, because then you get to use a curly cord if you want.

A lovely keyboard built into a kitchen cutting board.
Image by [androidbrick] via reddit
The switches are mostly Gateron EF Currys, though [androidbrick] left some of the original Gateron G Pro 3.0 on the stabilized keys just for comparison. As you might imagine, the overall sound is much deeper with a wooden bottom. You can check out the sound test on YouTube if you’d like, though it’s pretty quiet, so turn it up.

Those keycaps look even nicer from top-down, which you’ll see in the sound test video linked above. Just search ‘JCM MOA GMK’ on Ali and you’ll find them in a bunch of colorways for around $20. Apparently, [androidbrick] was saving them for months, just waiting for this build.

Via reddit

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Keyboard Configurator

Have you ever wished you could experiment with different layouts super easily, just by adding or removing a few switches here and there and printing a new case? Well, [heyisjambo] says that it’s more than possible with menura, the modular keyboard system.

A collage of menura keyboards, which are modular via the VIK standard.
So many lovely options! Image by [heyisjambo] via GitHub
[heyisjambo] is happy with 36 keys, but is reduced-count-curious and wanted a way to explore without a lot of wasted time and PCBs.

At the same time, [heyisjambo] wanted to experiment with split vs. uni-body construction, and especially the different shapes that are possible when tweaking the angle and distance between them.

And as if that weren’t enough, there’s support for [Sadek Baroudi]’s VIK standard for interfacing data between PCBs, which calls for an FPC 12-pin, 0.5 mm pitch connector and allows for ultra-cool magnetic connectors. This way, you can easily add things like displays, trackpads, and trackballs in the between the halves.

Thanks for the tip, [calculus]!

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With All The Espionage

[Ziddy Makes] describes this cute little guy as a biblically-accurate keyboard. For the unfamiliar, that’s a reference to biblically-accurate angels, which have wings (and sometimes eyes) all over the place. They’re usually pretty scary to behold. Don’t say I didn’t warn you.

A cube keyboard with adorably vibrant pastel keycaps.
Image by [Ziddy Makes] via GitHub
But this? This is the opposite of scary. Sure, there are keys everywhere. But it’s just so darn adorable. You know what? It’s those keycaps.

This 16-key macro cube uses a Pro Micro and a system of PH2 5p ribbon cables to connect the four four-key sisterboards to the main board. A 3D-printed base holds all the boards in place. Out of all the switches in the world, [Ziddy] chose Otemu Blues. Clack!

Although it may take some getting used to, this seems like it would be a fun way to input macros. I can see the case for putting some rubber feet on the bottom, otherwise it might scoot around on the desk. That might be cute, but only the first couple of times, you know?

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Music Typewriter

This edition’s community build comes from the Yes They Could, But Should They Have? file. Well, I ultimately say yes, this is intriguing. Redditor [dj_edit] looked at the venerable Model M and thought, this buckling-spring masterpiece can yet be improved upon. Yeah! Well, to each their own. I must say that it does sound great, especially with the solenoid feedback enabled via rotary encoder. Just check out the typing test.

To be clear, this is essentially a new keyboard that fits inside a Model M case, but that alone is quite a feat, especially if you consider the curvature of the backplate. Because of this hurdle, [dj_edit] went with 1 mm FR4 for the switch PCB, which is a nice compromise of sturdiness and flexibility.

Underneath those stunning reproduction keycaps are Kailh box white switches, which are pretty chonky-sounding on their own. But turn on that sweet solenoid action and you really get noisy.

Those box whites are sitting in hot-swap sockets, a design decision that kind of made things difficult because of the curvature. [dj_edit] ended up using an acrylic plate that gets bent to match the curvature by the switches themselves.

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Hackaday Podcast 052: Shorting Components, Printing Typewriter Balls, Taking Minimal Time Lapse, And Building A Makerspace Movie Prop

Hackaday editors Elliot Williams and Mike Szczys recap a great week in hardware hacking. There’s perfection in the air as clever 3D-printing turns a button and LED matrix into an aesthetically awesome home automation display. Take a crash course in RF modulation types to use on your next project. Did you know the DB-9 connector is actually a DE-9? Building your own underwater ROV tether isn’t as simple as it sounds. And Elliot found a treasure trove of zero-ohm jumpers in chip packages — what the heck are these things for?

Take a look at the links below if you want to follow along, and as always tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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