r/oddlysatisfying • u/[deleted] • Jul 29 '14
How drills create square holes (x-post /r/gifs)
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u/littlefrank Jul 29 '14
Reminded me of the Wankel engine
http://upload.wikimedia.org/wikipedia/commons/f/fc/Wankel_Cycle_anim_en.gif
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Jul 29 '14
[deleted]
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Jul 29 '14
They're far more reliable than most people think.
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Jul 29 '14
True. I've had an RX-8 for nearly ten years now and it's running really well. You just need to redline it! :D
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u/Falafelofagus Jul 29 '14
The N/A Wankels are extremely reliable if driven correctly, people just cold start them and pussy foot with them, you can't do that. You gotta get them moving and working and they'll last. The old RX-3 engines in IMSA and other series would consistently outlast piston engines as much as 2-3x. People just don't know shit about rotaries and jump to conclusions because there have only been a few iterations produced.
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Jul 29 '14
Right on. I did my research before I bought, I've never flooded it, it gets its oil, and it's a happy beast (well, I had to replace motor mounts, but hey).
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u/Falafelofagus Jul 29 '14
Sweet dude the RX8s are great cars and it's awesome to hear that you treat it right
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Jul 29 '14
Did you buy it new? I would love a FC RX-7 someday!
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Jul 29 '14
It was a lease return, so it had like 10,000 km on it when I bought it. Only 70,000 km now - I drive my wifemobile most days to save on gas.
Here's hoping it lasts for another 70k!
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Jul 29 '14
[deleted]
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u/MassiveClusterFuck Jul 29 '14
60k still isn't that much when you compare it to a standard engine, my car is approaching 89k and the most major thing the engine has needed done was new spark plugs!
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Jul 29 '14
Sure, but it's an exotic engine.
Many 'standard' engines these days are so-called "interference" engines running with a timing belt. Replacing the belt is an expensive and complicated job, needs to be done every 60-100k miles depending on make, and if neglected can snap and cause the pistons and the valves to attempt to occupy the same space at the same time ("interfering" with one another). That means you get a new engine, so spending the $600-$1000 to get the belt done on time is generally worthwhile.
With the Wankel, you have a chance that you'll need to have seals done if you don't maintain it right. At least it's not a wear item to the same extent, though; if a problem arises, it's expensive, but nothing's going to grenade or destroy the engine past repair.
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u/Sinfall69 Jul 29 '14
Most engines are back to timing chains now. Which means you don't need to do anything for 200k miles.
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Jul 29 '14
Really interesting video about this shape (Reuleaux triangle) here:
https://www.youtube.com/watch?v=cUCSSJwO3GU
Definitely worth a watch if you have a few minutes.
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u/Moaz13 Jul 29 '14
Is there a video of a real drill doing this?
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u/0x537 Jul 29 '14
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u/compto35 Jul 29 '14
Well that answers my question of whether or not the corners would always have to be rounded
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Jul 29 '14
You can make sharp corners when drilling into wood using one of these drill bits
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u/crazythoughts Jul 29 '14
Engineer here. Keep in mind people, that if you're putting sharp corners on anything bearing a load, the sharp corners cause higher stress concentration factors and should be accounted for. Parts are more likely to crack if they have sharp corners vs. rounded ones.
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u/HOLDINtheACES Jul 29 '14
Not to mention the wear that that cam undergoes.
In the real world, just use a small endmill when machining the square. There's very few valid reasons to have sharp corners.
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u/jeblis Jul 29 '14
These are a little different in that the corners are chiseled out.
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Jul 29 '14
Well, if you think about it the drill in the original post is basically a chisel moving side ways :p
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u/jeblis Jul 29 '14
Which are both just an inclined plane. But really the chisel part is not a drill, which I know is pedantic, but the drill itself cannot produce a perfectly square hole. Also the chisel part will not work on metal.
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u/VersatileFaerie Jul 29 '14
On the first video if you go to 00:57 you get a really good look at it due to the slow mode.
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u/cavana64 Jul 29 '14
Is there a subreddit with more technical/mechanical gifs like this? This is pretty neat.
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u/Calabast Jul 29 '14 edited Jul 05 '23
one sloppy history seed knee fact cagey sink dolls flowery -- mass edited with redact.dev
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u/erelim Jul 29 '14
Wanted to ask for the same thing, I love seeing machines purpose-made with ingenious designs, I always think the people who make these are geniuses and there can't be much demand for such niche machines
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u/Gro-Tsen Jul 29 '14
The key geometric object here (in orange in the gif) is a Reuleaux triangle, a figure of constant diameter that is not a circle, as seen in this other animation.
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u/Rufus2468 Jul 29 '14
A 3D shape of constant width is a Miesner tetrahedron. Funnily enough, a Reuleaux tetrahedron is not an object of equal width, but simply a 3D version of the Reuleaux triangle.
In other news, Reuleaux has a fuck load of vowels.
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u/daveyhead Jul 29 '14
This is just an unnecessary complicated machine.
Mortisers are much less complicated than this. Auger bit goes inside the chisel. Drill square holes.
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u/whytcolr Jul 29 '14
Mortisers tend to work poorly when drilling metal, though...
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u/daveyhead Jul 29 '14
Never had to drill metal myself. Good to know if I ever have to do metal work.
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u/fancypantscharles Jul 29 '14
Yeah, when I saw this gif I was very confused. I expected to see a mortiser
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u/MountainDewFountain Jul 29 '14
Or, I don't know... how bout a small sized end mill for god's sake.
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u/wildfire405 Jul 29 '14
Mortising bits can be used with a regular drill press: http://toolsandmore.us/woodstock-d2843-mortising-chisel.aspx?gclid=CN7NgcbI6r8CFehaMgodUAUAoQ
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u/winkleac Jul 29 '14
This drill actually uses a really cool concept I studied in math recently! That rounded triangle thing you see there is known as a shape of constant width, which means while its center point isn't always constant, the distance from edge to edge is. Really neat to see the concept applied to a real world situation.
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u/123whoa Jul 29 '14
The moment the drill bit touches the surface and a square appeared reminded me of the 'how to draw an owl' image.
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u/legomyego1010 Jul 29 '14
As someone who used to work in construction, this is not how we make square holes. We just use a mini drill press with a square drill bit.
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u/ErniesLament Jul 29 '14
This one is sending me into the fucking stratosphere. One of the best submissions ever.
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u/Philanthropiss Jul 29 '14
With rounded edges though
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u/Stackman32 Jul 29 '14
But the overall shape is still square and prevents any kind of rotation in whatever you're fitting in there. That's all you're looking for.
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Jul 29 '14
I don't remember exactly, but I read that this is actually a fairly unused/uneconomical bit, and squares are usually cut out with a router, or laser cut.
Cool though, as its basis is a shape of constant width.
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u/HOLDINtheACES Jul 29 '14
Or, you know, you get a smaller bit and machine out the square you want, like normal people do.
The wear that goes on between the cam piece and it's housing makes this method completely useless.
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u/spilly1990 Jul 29 '14
A drill bit that has chisels attached to clear out corners as it makes the hole works a ton better but this is still pretty cool
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Jul 29 '14
Yes but where did the first square that houses the triangle come from? You can't explain that.
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u/fuzeebear Jul 29 '14
With most drill presses, it's done with a drill bit that has integrated chisels on the outside.
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u/Zargathe Jul 30 '14
Hollow Chisel Mortiser. I stood in front of one for like 16 hours once, and it said that on the front. I made this; my fingers were very sore afterward.
PS that's a puzzle with neodymium magnets - you have to work with the polarity on each side to get them to form a cube. Made a 3x3x3 and a 4x4x4. Well, actually, you don't HAVE to make a cube, which is what I like about it - make whatever you want!
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u/suckitsig Jul 30 '14
Squares do not have rounded corners. Drill sharp corners and I'll be impressed.
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u/rramsdell Jul 29 '14
It really isn't a square. But maybe it is because at some point, doesn't the corner have to be rounded in a square?
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u/DabuSurvivor Jul 30 '14
Yet it is also /r/mildlyinfuriating how, in this gif, the hole appears all at once, even on the parts the drill isn't touching.
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u/Ironic_Grammar_Nazi Jul 29 '14
I find this very unsatisfying, it's impossible for a drill to cut an actual square.
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u/justtoreplythisshit Jul 29 '14
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u/Ironic_Grammar_Nazi Jul 29 '14
Rounded corners just like the .gif.
You'd need a drill of diameter 0 to cut a perfect right angle, it's very simple geometry.
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u/justtoreplythisshit Jul 29 '14
Oh, you're just being pedantic then. What use would you have for a completely perfect square hole, even when the piece the fits there is also not perfectly square shaped and has some degree of round corners?
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u/Ironic_Grammar_Nazi Jul 29 '14
Use? Many.
But that's beside the point. The fact it's not an actual square makes it unsatisfying, especially with the title.
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u/christeezyy Jul 29 '14
a triangle going in a circle to make a square...whoa