dual_sport_dork 🐧🗡️

Progenitor of the Weird Knife Wednesday feature column. Is “column” the right word? Anyway, apparently I also coined the Very Specific Object nomenclature now sporadically used in the 3D printing community. Yeah, that was me. This must be how Cory Doctorow feels all the time these days.

  • 29 Posts
  • 1.37K Comments
Joined 2 years ago
cake
Cake day: July 20th, 2023

help-circle

  • I’m assuming glass printer beds are supposed to be tempered, and just an FYI for you or anyone else attempting the hardware store or score-it-yourself method, the glass you wind up with will not be tempered and will also have exceedingly sharp edges and corners. If you have access to a belt sander with a suitably fine belt you can at least round off the sharp bits.

    Untempered glass probably won’t deal with thermal loading very well, either. It might work, and it’ll be cheap, but prepare for disappointment.





  • Stuff made in China for domestic use bears little to no resemblance to the stuff that Chinese factories are contracted to make for export.

    So much so that two doors down from my work is a place that does a booming business whose sole purpose is to allow people in China to purchase made-in-China stuff that’s only sold in the US that they can’t get at home and ship it back to China. It sounds absolutely asinine but there’s a huge market for it and those guys are busy all day long packing stuff up and cramming into shipping containers to send right back to where it was made… but can’t be bought.




  • You can get a rough estimate of how much of those reliability figures are down to absolute scattershot luck of the draw, because Roper’s (Whirlpool) only laundry machines on the market are literally rebadges of the only Amana machines (also Whirlpool) with no mechanical changes whatsoever, but they score “better.” Squinting at that image, it appears Amana is possibly #20.

    Also, the Kenmore bar is complete bullshit since Kenmore/Sears never manufactured a single appliance at any point in history. Every Kenmore model is actually a rebadge of some other manufacturer’s product (handy lookup chart located here) so the build methodology can vary wildly from model to model. So the fact that these are not separated out into their actual brands given how trivial this is to do indicates to me once again that Consumer Reports does not actually have any idea what the hell they’re doing.

    Even if you want to group things just by their nameplate since that’s what the consumer will see, fine. But those examples in particular need to have a big fat asterisk next to them and an explanation of what’s actually going on behind the scenes.


  • melt ceramic

    If you’re melting crockery in your microwave, I assure you whatever it is you’re using is not ceramic. Even the earthenware stuff that cheap coffee mugs are made out of has to be heated to upwards of 1000° C just as part of its hardening process, never mind melting.

    You can absolutely get silica gel beads hot enough in a microwave to melt and deform plastic containers, though, including those faux stoneware textured ones. Beware if what you have is not actually Pyrex or ceramic.

    I cook the shit out of my silica gel beads in the microwave in an old ceramic pie dish I have no other use for. There isn’t a mark on it. Although I will say, you probably want to microwave your beads gently anyway because at high power levels the moisture flash boils out of them fast enough to cause them to split and shatter, or occasionally leap out of the dish like popcorn.


  • I have a Dell Axim X50v in a box somewhere. I imagine the battery is toast and I’ll probably have to keep it in its cradle to remain powered. It was a hell of a machine for it’s day.

    I went through a succession Windows CE/PocketPC machines back in the day, starting with a Casio Cassiopeia E-115, then an Audiovox Maestro which was a rebadged Toshiba, then an HP iPAQ 2215, and finally the Axim.

    The displays on the Maestro and the Axim were really something, and I wish someone would bring these back for a modern smartphone. They were rotten at color accuracy, but both had transflective displays that were fully readable even in direct sunlight. The Axim X50v also had a full 480x640 screen resolution which blew the first few iPhones out of the water on pixel density and even gave the iPhone 4 a run for its money. “Retina” display, my ass.

    I had a Microdrive bunged into the CompactFlash slot on my Axim which was… several gigabytes, I don’t remember how many. I kept it packed with MP3’s, and I had a custom wallpaper with a white-on-chartreuse silhouette of a pacifier on it with the legend, “All 10,000 Songs On Your iPod Suck.”

    But then the entire PDA market got swallowed in one gulp by smartphones.






  • I don’t print TPU on a textured bed. I use the flat side of my build plate, which I also have coated with a giant sheet of Kapton/polyamide tape. Peeling the completed parts off of the smooth surface has never been an issue.

    A word to the wise: Always run with a sheet of polyamide tape if you have a flat build plate. This will go a long way towards protecting the finish and flatness of your plate, and I have definitely saved myself a couple of times when having a Z offset that was too low and thusly crashing the nozzle only into the tape and not the surface of the expensive plate itself. You can apply adhesive and clean the tape’s surface just the same as the PEI surface of your plate, but once it gets worn out or chewed up or otherwise no longer produces parts with a pretty underside, you can just peel it off and reapply. If you’ve already fucked up the surface on your plate you can also paper over this with a layer of tape which will smooth out small scratches, pock marks, and other imperfections.

    And if you really need to employ the nuclear option to get a stuck part off of your bed (i.e. if you’ve printed something with a sticky filament such as TPU or PETG and happened to have your Z offset way too low) you can peel the tape off along with the part. The tape is unlikely to survive this process, but a pack of 12 sheets is only $20 or so.


  • That is a mighty chunky thread!

    I can tell you from experience that the strength of your part is not likely to be due to the design or pitch of the threads but rather down to the layer adhesion strength of your print and whatever material you’re using. Even a dinky 1.0mm thread pitch is perfectly capable of ripping the layer lines of a print apart, and your point of failure will be the layer immediately below where your countersunk head contacts the base of your nut and/or part it’s screwed into, the exact moment you overtorque it.

    I have a bit of experience with this sort of thing. Actually, these days, probably rather a lot.

    Your thread creation approach is similar to mine but I prefer to use an additive helix on the male thread, and then a matching subtractive one on the nut or female side. I find this makes it a little easier to tune for good engagement. If you need to make multiples in a single assembly you can draft clone your sketches to make them all the same. Change one, change them all. You can just use triangles to create both the male and female helices, unless you want to make the tips of the threads flat in which case you can draw a trapezoid.

    There are various threaded fastener workbenches and plugins available, as others have mentioned, but I prefer to do things the hard way since I came up using FreeCAD in not only the pre-1.0 era, but even pre-0.21 back when the hard way was the only way to do anything and there was no path forward except to Git Gud. If you have specific design parameters in mind I find that building screws manually provides much more flexibility. That, and not having your file explode in your face if you happen to open it on a machine that doesn’t have your full selection of plugins installed is always nice.


  • You won’t. You’ll get annihilated by the next Chinese competitor who produces a piece of shit machine that breaks in 13 months like clockwork (and has a 12 month warranty), but sells for 1/2 or 2/3 of the price of your machine.

    The average consumer is dogshit at conceptualizing the actual value of a product over its lifetime in proportion to its cost. They’ll just see that the next machine on display at Best Buy or whatever looks modern and costs less to buy up front, and then they’ll buy that one. When it breaks they’ll bitch and moan on Facebook and Nextdoor and write ranty one star reviews everywhere, and then wheel right back to Best Buy and buy another machine just like it.


  • This the argument I have with clients on a daily basis, in regards to all kinds of manufactured goods. People are astoundingly awful at understanding and visualizing inflation and the value of a dollar over time, even people who are specifically educated on this point and even work with it as part of their jobs. Everyone has some threshold beyond which they absolutely won’t countenance paying more than $X for Y, but this is always arbitrary and whenever the course of events drives the median price of whatever-it-is past that line they lose their minds.

    Durable goods manufacturing is a race to the bottom because it has to be in order to overcome everyone’s moronic preconceptions about what a product “ought” to cost. This isn’t just a capitalist greed thing, although it’s certainly that, too – corners have to be cut, panels have to be made thinner, it has to contain more plastic and less metal, because otherwise it’ll never be cheap enough for 99% of the population to agree to buy it and even then they’ll all still bitch about how shoddily made it is. Year over year every manufacturer has to figure out how to make it cheaper to slide under MSRP. The manufacturers who take the opposite strategy inevitably wind up as niche players, because as much as people spout that they’d happily pay more for a better built thing, the flat out truth is they’re all full of shit and to the nearest decimal point, none of them actually will if given the opportunity.