Leaves echo chamber ahhh WTF!
I post hobby stuff I'm working on. Everybody seems to care very little. I try to say stop being assholes and people hate for it.
Bias here seems typical for tech geekigarchy. After 2 years on Lemmy – echo chambers are also self selecting and self filtering.
Joining over half a million homeless feral humans
"Randomize seams" uhh no, design parts with seams in mind if they are critical. I often add a small 0.3mm double chamfer "zipper" on a surface because it will accommodate the inconsistency and reduce it by forcing the root inside the body. I've made my own infill structures and patterns lately too.
You can just slap a dial gauge on the gantry and move the X/Y manually to see exactly what the deviation is. A decent second-hand dial gauge on eBay will run you $20 shipped.
If you get into the weeds, there is not an accurate method of triggering any form of mechanical stop that involves touch or a hall effect probe. You must get into optics for real accuracy, but that is nonsense for the materials and scope of printing. You would need to eliminate many other variables like the filament accuracy and how backlash and step accuracy are eliminated as issues.
As a former owner of an auto body shop with employees, most people do not know what clean is or how tooth is required. Like isopropyl alcohol has its place but is ultimately extremely weak at real cleaning problems. In automotive paint, silicone is a major problem. It primarily comes from tire dressing that makes them look slick black. The amount of effort it takes to remove that junk for automotive quality work is insane. Most chemicals just push the junk around but leaves or dilutes the issue often making it worse. One of the big tricks in automotive stuff is (to use a chemical cleaning step first but -) a few drops of dish soap in the wet sanding bucket. The light soap will keep the sand paper clean and working longer, but makes most work also cleaning work. Anyways, dish soap can be very effective. Acetone occasionally on a surface is also effective. Virgin lacquer thinner is the strongest common solvent but it can react with lots of stuff and you are unlikely to find true virgin solvent. The recycled stuff has a paint stripper component in it that will cause epic nightmares and reacts with almost all plastics. Acetone is much cleaner and consistent unless it is sold for junk like nail polish.
The general rule of thumb is to assume a mechanical tooth adhesion is the primary form of bonding unless there is a catalyst involved (2k urethane/epoxy primers/clear). That rule can easily apply to 3d printing and bed adhesion. I see a lot of the same types of effects from different surfaces and filaments. In automotive paint, there are even special adhesion promoters like Bulldog for spraying plastic parts ahead of other finishes. I had other adhesion promotion tricks too, like a mist coating of clear coat. The main trick with all automotive paint adhesion is to know what grit or "tooth" each thing you're spraying wants to grab onto and prep accordingly. So in 3d printing I use a similar approach with the general safe bet of sanding my smooth build plates to 600 grit. With sanding, do not start dirty, like you're trying to embed junk into the surface. Start clean, then knock off the shine to a smooth and consistent matte finish on the entire surface. When it comes to sanding like this, edges and any anomalies are absolutely forbidden to sand. Never touch your edges until last when everything else is done. Edges are always thinnest and most vulnerable to causing issues especially for the inexperienced. You match them to the rest of the matte surface carefully at the end.
Clean a smooth build plate with acetone like once or twice a year and then sand it to matte, clean that with dish soap, then alcohol with each print. That will completely eliminate contamination as a cause. If you have old skool clean glass with no coatings as a build plate, sanding is optional because you can use something like lacquer thinner or less effective acetone to get it absolutely clean.
Perfect first layers are possible with enough fussing with the software. If you really want to level the bed with hardware, use a dial gauge clamped to the extruder. That will remove all of the averaging and inaccuracies from probing if it is a quality gauge that is smooth and not sticky. You would need to get into optics for true accuracy like with closed loop control systems that are an order of magnitude more expensive than 3d printers. 3d printers are precision machines with no accuracy. The 0,0 home location is always slightly different, but all measurements are based upon this location. This issue becomes relevant with IDEX and CNC. Going well beyond these – in optics accuracy requires a defraction grading and alignment of light wave patterns. I so want to get into that one to grind my own telescope mirrors. Typically accurate machines use a flag of metal sticking out somewhere at a known location and an optical encoder switch that gets interrupted without anything touching as this is typically the closest you'll get to real accuracy down to the clock and instructions timing of the interrupt routine in the microcontroller.
If you have v-roller wheels on extrusions, one other major potential issue is that extrusions have a relatively large twist tolerance component in their specification. It is extremely difficult to detect this kind of twist, but it is a major potential issue. It generally requires a high metrology grade granite surface block and parallel sticks to measure twist in a precision instrument's linear bearings... as far as I understand it. I have seen such things being measured but have never done so myself.
Very cool. I was thinking about ways of making a potentiometer knob on an audio amp more visually interesting. The moire effect might be one to play around with.
I don't think I would trust this one in practice, but the effect is interesting. I found it far more necessary to learn the vernier scale with micrometers. It felt much more useful understanding the practical limitations and scope of when to use calipers versus a mic. While there are super accurate calipers, relatively cheap calipers and micrometers are far cheaper and easier for most people to access.
When it comes to radius gauges I trust these more than any of the others I have tried:
I know this kinda isn't the point, but using it as an excuse to share – the fishing leader line to hold a set like this is key to making them super handy. Unfortunately I have only used micrometers on a few 3d printing projects. Those are more used within the machining realm.
here is what is inside
took way too long to figure out/make a small gif in Linux and even this one took hacking slow frames to get under 300kB with gnome screen capture, ffmpeg, gimp, and gifsicle to capture a simple FreeCAD turntable.
Thanks. I'm not worried. I have nothing to lose and anyone scraping has enough to find me if they really wanted to. If they are after some physically disabled guy, hopefully they do a better job than the person that left me like this.
This has been through many days of iterations and designs. Most involved over center mechanisms or wheel levers before this design dawned on me. The bottom right is how it prints. The "spring" is a double forked 10mm bridge in the last few millimeters inside the enclosed print. The visible "clamp" is connected to the spring by forking into two paths that branch beside the tube that the spade terminal is inserted through. The clamping force is not great but it is sufficient for a reliable basic electrical connection for bench testing. The pictured driver is a very small tweeter and is barely held in place with both wires inserted between the print and spade terminal.
I wanted something that would fit on the faceplate of the little hacked audio amp enclosure I have been designing. I think 6 of these will barely fit across the front and under the actual circuit board assembly.
This one might be worth the hassle of setting up an account and sharing on printables if it does not require the goggle server connection like it did in the past when I tried.
The thing is, I dial in my prints to 0.3mm clearances and this absolutely requires that clearance. I do not care to print other people's designs because most are really terrible for things like supports, designing for 3d printing, clearances, and general slop. I'll occasionally toss someone else's STEP or STL in FreeCAD and rebuild the thing but I usually just use some conceptual idea of anything I see elsewhere. I think with this one, I could share it as a negative Boolean STEP file to be most useful. Then it would only require others to import and do a boolean cut operation to use the design. Maybe I will do so if it works out well in my enclosure with 6 of these all resolving well and functional. What do you think, would you ever care to find and print something like this in one of your designs? Do you think anyone would even understand the value of printing such fundamental componentry instead of buying hardware and gluing it together with a 3d printed design? Like, this could easily be configured to use a loop of solid core copper wire as the connector terminal for a low voltage bench power supply that requires no other hardware.
Also, I had a rather irritating encounter with Dessalines (the Lemmy Dev) on ML a few days ago. I want to move off of Lemmy but I kinda like the rest of you, so maybe piefed is an option. I haven't looked into it deeply as I thought rust was worth supporting more, however empowering these guys as authoritarians is not on my list. I'm in a position to move this community if people want but like I always say, I'm just the janitor here. I do not matter. I would just as soon give this place to someone else if that is best for the community. I only want what is best for all, which is probably stability first and foremost, but if you feel otherwise, maybe mention it, maybe we'll make it happen.
US is not supporting Russia, but Iran is. Israel is atrocious and it would not surprise me at all if they absolutely know about Oct 7th well in advance. It was the result if their prejudice and Palestinian concentration camps before Oct 7th in either case that caused the initial attack. However it was not entirely without cause like with Russia in Ukraine. Everywhere is complicated. The USA is super polarized and in pretty bad shape, but it us not exporting suicide bombers. Is it better to target with 10 million dollar munitions remotely no, but those are not targeting crowds of people as the primary goal
It was the change in Syria and the mountain on the boarder that Israel now controls that changed the geopolitical situation and strategy. The radar shadow of that mountain was what prevented Israel from having an opportunity to stop or influence Iran's nuclear policy. Some deeper depth geopolitical youtubers have done uploads on this change and implications. The position will likely end up back in Syrian hands eventually... or it might. Again like I have said elsewhere, I don't support Israel or their escalations but Iran is shit. They are supplying arms to Russia, exporting terrorism, and run by a disordered misogynistic group of men that kill in the name of fantasy and a collective imaginary friend that no one has ever had a real conversation with. That is fucking cave man level bullshit from anyone anywhere.
I don't support either.
Found out about this website from today's Geology Hub uploaded on YT
https://www.youtube.com/watch?v=v75f530yFOY
This crystal doubles images, meaning that if you look through it that anything on the other side whether that be text, a person, or a photo of a volcano will appear to be doubled. But, why does this unusual optical property occur when utilizing a crystal of calcite? The answer is a fascinating phenomenon known as birefringence, which this video will explain through the expertise and analysis of a geologist.
This is the about-page of which text continues past the posted image on the left side:
https://www.mindat.org/a/aboutmindat
Here is the link to the discussion groups page pictured:
https://www.mindat.org/discuss.php
And as a further aside, the image was made with an F-Droid app that is new to me but popped up 3 months ago apparently and has a lot of great features for stitching images and creating content:
0.25mm nozzle, clear PETG, Prusa, 6mm standard headphone jack, upcycled broken bluetooth headphones, three times larger battery, snap fit with no hardware, FreeCAD, 2nd print iteration, listening to it now, no tricks - it holds together firmly and is usable and actually sounds better than the original by a long shot from better headphone drivers I guess or proper soldering, oh and power button built into the flex of the design, OC only posted on Lemmy
The info wore off the grip and I do not recall what it was. I think it was a German brand. These have been one of my favorite tools for a decade. The jaws are much more narrow than what is typical for side cutters and these handle like a surgeon's scalpel. Best of all, they can be sharpened many many times. Unfortunately, these are getting close to end of life from all of my sharpening and pivot pin wear. I want to get another set, but I have never been able to figure out the brand to find them again. They were given to me by a tech for a computerized Guru bicycle fit machine we had installed in one of our bike shops in 2012.
CAD modeling and hacking some old junk audio stuff with help
Lots of people seem to like custom keyboards and programmable HID widgets. Saw this and it seems interesting. Being Adafruit it is commercial on some level but also well documented for replication and mods that are more useful than the average shared project.
https://www.youtube.com/watch?v=A8RW3y0CIgw
YT description:
Build a 3D printed USB chorded keyset inspired by the original Doug Engelbert "Mother of all Demos" keyset from the 1960's. This 5-finger keyset lets you type without moving your hand, entering full words and phrases by pressing multiple keys simultaneously as a chord. Read more link below
Learn Guide https://learn.adafruit.com/usb-keyset
USB Keyset Learn Guide: https://learn.adafruit.com/usb-keyset/
cross-posted from: https://slrpnk.net/post/23118905
Look up Gentoo, Arch, and RHEL for documentation. You can also reference linux-hardware.org to potentially check what others are running. Scan and uploaded your stuff to share with others too. It is easy and only takes a minute.
UEFI is a can of worms. I don't know enough to be more helpful. When messing with SB keys, Gentoo had good info when I needed it. Fedora uses the Anaconda system for SB stuff and is quite advanced. That is another place to look for clues.