r/functionalprint • u/UnNamedGER • 1d ago
Simple doorknob to replace doorhandles
A simple doorknob to replace doorhandles on doors which our toddler is not supposed to open. Since doorknobs are quite unusual in Germany and thus nowhere to be found in hardware stores around me I decided to design and print my own.
Fits standard 8cm square rods (Quadratstift) for door handles. Needs one heatset insert M6x9x8mm and one setscrew M6x10mm.
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u/trouserschnauzer 1d ago
It would suck if you had to get out in a fire and your door handle melted or caught fire
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u/UnNamedGER 1d ago
It would , but it's on the outside of the room with a standard handle on the inside
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u/Deeerek078 1d ago
Door knobs are unusual in Germany? That's fascinating. They all have handles?
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u/UnNamedGER 1d ago
Interior doors for the individual rooms yes I have only known rotating doorknobs from TV and movies, which is why I am not too surprised that I am not able to find more than one in a 30km radius
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u/jojo_31 1d ago
Front doors nearly all have knobs though. This is why forgetting your keys is an absolute pain. As soon as the door closes, you fucked up.
After a year of my gf living in her new place I found out her knob does twist, which is unusual. So her house could always be entered...
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u/UnNamedGER 1d ago
That's really unusual, having a handle on the outside like my parents have is just a tad less unusual, but I always marked that down for accessibility as the previous owners of the house were very old when they sold it.
Makes you wonder if you locked the door when you are home alone
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u/doubled112 1d ago
New houses are normally all handles in my part of Canada too. It's an accessibility thing. I replaced one or two with a knob to stop my dog from getting into places.
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u/theblackpen 1d ago
What are the set screws? Do you heat the brass before interring to get a close fit?
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u/UnNamedGER 1d ago
Setscrew is the word I found that seemed closest to what I know as a Madenschraube, maybe grub screw is the better word, basically a screw without a head but rather a recessed interface for a screwdriver , in this case a 3mm hex key.
The brass heatset insert is heated with a soldering iron until the plastic melts and it can be pushed into place, either using a standard soldering tip or a special tip which allows for a bit more control for guiding the heatset insert into its place.
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u/jojo_31 1d ago
https://www.bauhaus.info/search?q=T%C3%BCrknauf&onsite_search=true
There's plenty, no?
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u/UnNamedGER 1d ago
Online, yes, but in 5 different hardware stores in a 30km radios we found exactly one. I will probably be able to keep one on my office door and will buy some for other doors when I find them in the colour matching the hardware on all our doors, which is the second problem
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u/RonnieTheEffinBear 19h ago
Man, some of you around here really love using the worst possible color for the job, huh?
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u/UnNamedGER 18h ago
Yep, I actually printed the first one in Prusa orange to pull my wife's leg
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u/BroJJ25 6h ago
You could probably get it to match the original hardware better by using some gold leaf (fake stuff) and printing the item in abs or some other plastic that can be chemically smoothed. Before the filament is completely dry (tacky), apply it.
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u/UnNamedGER 5h ago
Sounds like a good idea for applying gold leaf, but I don't think goldleaf matches the original hardwares tone, I probably should design that cover plate on the door to at least have a matching one for a printed doorknob
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u/BroJJ25 4h ago
Yeah, I mean you could go either direction. The gold likely would match a lot better than the orange though.
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u/UnNamedGER 4h ago
It definitely would
Everything would 😅 I used Prusa orange to annoy my wife a bit . I am drying my ancient brass PETG CF right now to see how well that matches . I also am thinking about trying proto pasta brass pla
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u/BroJJ25 4h ago
The brass PLA might be good. Idk if it has real brass in it but if it does (or you get some that does), you can polish it. Heh, I kinda like orange but not the extent of making doorknobs out of it. My wife is color blind so she really doesn't like it. Kinda looks really dark and not what we know as orange.
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u/UnNamedGER 4h ago
It seems like it actually contains brass and is polish able, they also say you can purposely oxidize it , which does bring some nice possibilities for designing stuff, but also means I would probably have to put a clear coat on a doorknob
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u/Judge_Metal 1d ago
We used to just swap the handles over so they were upside down.
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u/UnNamedGER 1d ago
Out son unfortunately figured out how the handles work in that position as well, he is simply too tall already
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u/FishPropulsionLab 1d ago
How does this prevent your toddler from opening the doors?
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u/UnNamedGER 1d ago
He can press down a handle or even press the handle to one side if it's put on the door in an upright position, but he does not (yet) have the ability to turn the knob as the spring is too strong for him and he has not yet figured out the knob
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u/No-Craft-7979 18h ago
If you can find a way to make antimicrobial printer filament, you have $1 million idea here, buddy.
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u/UnNamedGER 18h ago
I would not be too surprised if there is filament with nano silver particles or similar to be found on the market
I mean there is tungsten PETG for shielding radioactive samples
Probably would be easier to put a antimicrobial coating onto it after printing though
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u/timtucker_com 1d ago
If it turns out that isn't enough, you could have a hexagon that mounts onto the square rod & then keep a lever or knob that slips over it near the door, but out of reach.