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/r/specializedtools

49.1k

Radius Measuring Guage

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all 739 comments

gommander_geen

2.6k points

3 days ago

It's like a crossbow but for maths

E1CH3

450 points

3 days ago

E1CH3

450 points

3 days ago

Load it up with a compass and you’ll have yourself a classroom war

To_Circumvent

88 points

3 days ago

Which is one of the first steps to joining a fine crew of business, like that of The Crimson Permanent Assurance.

ElminstersBedpan

48 points

3 days ago

No one expects the Crimson Permanent Assurance.

phlux

16 points

3 days ago

phlux

16 points

3 days ago

Thats quite the angle you have there

mud_tug

41 points

3 days ago

mud_tug

41 points

3 days ago

You joke but here is the Tomahawk Angle Trisector It trisects angles.

LovableContrarian

24 points

3 days ago

Tomahawk Angle Trisector It trisects angles.

Couldn't they have come up with a more descriptive name?

JorfimusPrime

20 points

3 days ago

Well, "The Tomahawk Angle Trisector that Trisects Angles for your Convenience" was taken

TheMcDucky

12 points

3 days ago

Good old TATTAC

lightspeeed

10 points

3 days ago

Does anyone have a video illustrating the use of this tool? No scalping videos, please.

mud_tug

14 points

3 days ago

mud_tug

14 points

3 days ago

lightspeeed

2 points

3 days ago

perfect. Thanks!

It's amusing that its geometrically impossible to draw a tomahawk in place. At what angle does the tomahawk fail?

mud_tug

3 points

3 days ago

mud_tug

3 points

3 days ago

Just draw an arbitrary tomahawk somewhere outside the angle and then transfer the necessary lengths using the compass. Or treat the tomahawk as three congruent right triangles, same thing.

TastySpare

5 points

2 days ago

No scalping videos

Now you're just splitting hairs.

[deleted]

3 points

3 days ago

[deleted]

3 points

3 days ago

[removed]

karlnite

2 points

2 days ago

karlnite

2 points

2 days ago

Mmm sineful.

zyzzogeton

2 points

2 days ago

I'd like to see a compass do that!

ag408

15 points

3 days ago

ag408

15 points

3 days ago

“Aye sir, where can I buy one of them math crossbows?

639wurh39w7g4n29w

83 points

3 days ago

Aisle 5, right next to the trigbuchets and the calcupults.

cantadmittoposting

20 points

3 days ago

Everyone knows the trigbuchet is the superior siege calculator

TheGalaxyIsAtPeace64

13 points

3 days ago

It can measure up to 300 mm on up to a 90° angle

experts_never_lie

2 points

2 days ago

However, it is not recommended that you use the trigbuchet at an exact 90° angle unless you are a good runner.

Kichigai

6 points

3 days ago

Kichigai

6 points

3 days ago

The superior Sine weapon.

exipheas

6 points

3 days ago

exipheas

6 points

3 days ago

Isle 2i.

NeokratosRed

7 points

3 days ago

x-bow

ShoMeUrNoobs

6 points

3 days ago

I have found X

faultycraftsman

2 points

3 days ago

And when you fire it you will find the Y

rbb_going_strong

4 points

3 days ago

Weapon of math instruction

Axebeard_Beardaxe

35 points

3 days ago

My comment cannot improve upon your excellence, but I felt like I had to say something. Well done, sir.

BigBluFrog

2 points

3 days ago

I laughed until my both sides hurt. Chef's Kiss This comment.

AreWeCowabunga

830 points

3 days ago

Oh hell yes. I want one. I don't know what I'd use it for, but I want it.

Picturesquesheep

908 points

3 days ago*

Grinds my gears that some people don’t get this. Sent my mate a picture of my newly assembled 3018 Chinese mini cnc and he goes “what’s the plan with it?”. I don’t fucking know mate I’ll think of something. I ended up drawing a cock and balls on paper, photographing it, tracing it in Inkscape, then having the cnc engrave it on a Lidl ham chopping board. Happy now lad? A plan, executed.

Edit someone asked so here it is:

https://pasteboard.co/JPNJgtj.jpg

Someone else asked what I think. I bought the cheapest one, I can’t remember the brand. I got the 5.5mw laser too. For the price (£170?) it’s pretty good. It takes a fair bit of work to get it running and it’s not as well supported online as the ender I’ve got so expect to troubleshoot on your own a fair bit. But not hard. The chassis is surprisingly well made, in that it’s all cut square and goes together well. You need to deburr everything but hey it’s dirt cheap. You will need to fettle to eliminate binding but no bother. I suspect they’re identical whichever brand you buy, although perhaps better quality stepper motors - mine don’t seem great but whatever. I’m not sure the laser is worth it - I can’t get it to focus properly but I haven’t really tried much yet, maybe sack the laser, get to know it, and just buy a better laser separately? The spindle motor will definitely get upgraded, although I think you can feed it 36v fine so I might try that first (supplied power block is 24v). Overall, excellent craic highly recommended. Also I 3D printed a pen holder for it so I can also draw cock and balls with a biro on things now too. I alsoOrdered a random selection of cutters up to 7mm end mill, that will be amusing to to try out.

tophyr

347 points

3 days ago

tophyr

347 points

3 days ago

I bought an old Bridgeport mill and a Clausing lathe. Girlfriend was supportive enough - my money, my garage - but couldn't understand for the life of her what I was planning on making.

More parts for the mill and lathe, dummy. Duh.

Picturesquesheep

92 points

3 days ago

Hahahaha that would be the 3D printer for me. Congrats on the mill and large I had to look up what kind of lathe it was, I know what a Bridgeport is though

TheFenn

66 points

3 days ago

TheFenn

66 points

3 days ago

A Clausing Lathe is for making wooden toys, traditionally for Christmas.

never0101

14 points

3 days ago

never0101

14 points

3 days ago

Seems legit.

godsbro

9 points

3 days ago

godsbro

9 points

3 days ago

So I knew this was a joke, but was curious as to what was special about a Clausing Lathe, turns out it's just a specific brand that doesn't really exist anymore. History

jr0405

18 points

3 days ago

jr0405

18 points

3 days ago

I shock myself when I 3D print something that isn’t for my printer or build something in my wood shop that isn’t for the shop

Slggyqo

42 points

3 days ago

Slggyqo

42 points

3 days ago

Step 1: buy a bunch of wood shop equipment.

Step 2: Make jigs.

Step 3: fail to make anything else.

Step 4: r/woodworkconfessions

jsbizkitfan

13 points

3 days ago

That's a sub I never knew I needed so much

Slggyqo

4 points

3 days ago

Slggyqo

4 points

3 days ago

I think it resonates with just about anyone who has ever tried to build anything physical.

Hell, it works for coding too, although that’s a bit easier to fix.

texasrigger

15 points

3 days ago

I've got a Bridgeport and an old Logan lathe (think southbend lathe). At the time I got them I knew they'd be handy but I wasn't fully sure what I'd use them for. Now I can't imagine how I got along without them. You're going to really enjoy them.

MCClapYoHandz

8 points

3 days ago

I’m jealous. I’ve been keeping an eye out for both, knowing full well that it would permanently kick my wife out of our small 2 car garage since my half is taken up with other tools. And I’d have to run 220V. And at that point I’d want to insulate the garage and rewire some other stuff. Basically there are a ton of reasons I shouldn’t get them, but if I see a decent deal for a machine in good shape I’m going to be so tempted.

Iphotoshopincats

7 points

3 days ago

Hell if your going all out install 3 phase and open your future options up

texasrigger

4 points

3 days ago

My Bridgeport is 220V 3 phase (via a phase converter) but the lathe is just 110 and plugs into a normal outlet. Something like that may get you going. Running the 220 in my case was easy since the shop (4 car garage and the main reason I bought the house) already had a 220 circuit for a dryer. I still use the dryer plug but either use it to run my phase converter or use it to run my 220v mig welder. I never need both so switching between the two is fine.

MCClapYoHandz

4 points

3 days ago

4 car garage? Now you’re making me think step one is a new house. The 2 car garage is my biggest regret with this house, because I wasn’t into the same hobbies when I bought it. No room to build onto it or build a workshop either. Did you buy your machines at auction or on Craigslist or something else? I’m in Texas also and I probably don’t even know the best places to look, but maybe that’s for the best.

texasrigger

3 points

3 days ago

Yeah it's really a separate metal building. The guy who built it used to build hot rods. I've got it set up with a passable woodshop, small machine shop, and commercial canvas shop complete with 6'x20' sewing table. I've got another small building that's got some other tools in it plus I'm building a small propane forge for it. I'm a sailmaker and sailboat rigger by trade so it's all my workshop.

The machining tools mostly came through buddies. I know several in the industry and people keep their eyes out for me. Lots of machine shops scaled back or shut down when the oilfield last crashed. If you hauled stuff off you could get it for scrap value or less. Craigslist and ebay are both good though if you are willing to go pick stuff up.

Apathyistheanswer

3 points

3 days ago

Oh man, picking up an old metal lathe was the best shop decision I ever made. I can't imagine shop life without one now. Ordering bushings, spacers, sleeves, etc? Never again.

insufficient_funds

6 points

3 days ago

I need to find a friend with a mill/lathe. I have a driven roller for my ancient belt sander made of aluminum- it’s been used so hard the aluminum around the bearing has worn away and now the roller doesn’t ride on the bearing properly. The thing was my grandpas and then my dads and now mine. I refuse to get rid of it bc if not for this damn roller (which is absolutely impossible to find) it would work perfectly.

-_Dan_-

7 points

3 days ago

-_Dan_-

7 points

3 days ago

Do you have a technical drawing?

SchwiftySkidgy

3 points

3 days ago

I envy you. I 3D printer a CNC and I love it, but a Bridgeport and lathe would get me all hot and bothered

TheWrongFusebox

40 points

3 days ago

What's the plan with it?

The plan is to have a mini CNC.

Brilliant plan.

dfreinc

13 points

3 days ago

dfreinc

13 points

3 days ago

sounds like it was worth it to me 🤷‍♀️

Mesozoica89

9 points

3 days ago

Give it to him for his birthday and simply say "Happy now lad?" on the card.

Picturesquesheep

2 points

2 days ago

I might just do that it’s in April hahahahaha

treerabbit23

5 points

3 days ago

The difference between a magician and everyone else is that magicians can make their will manifest.

ATangK

3 points

3 days ago

ATangK

3 points

3 days ago

Got one too. Started drilling the alu base though, and have had all 3 axes loosen off. Make sure to triple check the grub screws everywhere.

texaschair

12 points

3 days ago

That's because the base is pre-famulated amulite, surmounted by a malleable logarithmic casing in such a way that the two spurving bearings are in line with the panametric fan.

And don't forget to check the six hydrocoptic marzlevanes, or you could damage your ambifacient lunar waneshaft.

Chucklz

5 points

3 days ago

Chucklz

5 points

3 days ago

And watch your dingle arm!

Revolio_ClockbergJr

3 points

3 days ago

or you could damage your ambifacient lunar waneshaft.

I modded mine to solar and I’m never changing back

AlexanderRussell

2 points

3 days ago

wow this guy seems to know a lot about this stuff

imgur_com_y8suYkD

2 points

3 days ago

Does it effectively prevent side-winding?

FoodMuseum

2 points

3 days ago

It's technically side-fumbling that is prevented, but I knew what you meant.

cantadmittoposting

3 points

3 days ago

Here's the thing. You said "side-fumbling is side-winding."

Is it in the same family? Yes. No one's arguing that.

As someone who is a lather who studies panametric fans with ambifacent shafts, I am telling you, specifically, in jargon making, no one calls side-fumbling side-winding. If you want to be "specific" like you said, then you shouldn't either. They're not the same thing.

day1028RW

2 points

3 days ago

a man with a plan.

c0de_g0rilla

2 points

3 days ago

Hey internet stranger, got any more info about your CNC? I have a 3D printer (Ender 3 Pro) and it makes me want a CNC. Any suggestions or recommendations?

stopbeingatotalbitch

25 points

3 days ago

Can one buy this to measure the radius of another’s asscheeks?

r/nostupidquestions

sniper1rfa

12 points

3 days ago*

Only if they're round. It doesn't work for other curves.

TwelfthApostate

2 points

3 days ago

Mine are 100% round. You can measure me if you’d like

DoverBoys

15 points

3 days ago

DoverBoys

15 points

3 days ago

As an electrician, I would kill for this to measure cable bend radii. The tools we have at the shop are literally premeasured quarter pie pieces of metal.

sniper1rfa

8 points

3 days ago

They're not super expensive. Probably don't need to commit a crime to get one. Try eBay?

stratosfearinggas

5 points

3 days ago

Measure the arc of dat ass and see how much it will take to reach the centre point.

i486dx2

3 points

3 days ago

i486dx2

3 points

3 days ago

Fitting things to round things, of course!

Drawkcab96

2 points

3 days ago

Bring it out at parties.

digitalgoodtime

2 points

3 days ago

So do I. Do you know where I can find one?

SwampOfDownvotes

2 points

3 days ago

Seems like you would use it to measure a radius

SiON42X

2 points

3 days ago

SiON42X

2 points

3 days ago

I need this for measuring guitar fretboards

gothlaw

129 points

3 days ago

gothlaw

129 points

3 days ago

“Now you tell me.” - Eratosthenes

mcstafford

64 points

3 days ago

He is best known for being the first person to calculate the circumference of the Earth, which he did by using the extensive survey results he could access in his role at the Library; his calculation was remarkably accurate. Eratosthenes

à la explainxkcd

I can't seem to keep his name in memory.

completetrashperson

62 points

3 days ago

Just use the simple mnemonic device, "Earth Radius And The Other Stuff That He Equally Noted: Earth Stuff"

SagittariusA_Star

22 points

3 days ago

How do I remember what that mnemonic is?

completetrashperson

34 points

3 days ago

Just remember "Eratosthenes"

E1CH3

9 points

3 days ago

E1CH3

9 points

3 days ago

We all know that most people would use this to help measure girth

Intelligent_Moose_48

2 points

3 days ago

The scale calibration does not appear to go that small

Arsanick

84 points

3 days ago

Arsanick

84 points

3 days ago

Calculating uncertainty on this must be a pain.

namdnalorg

46 points

3 days ago

I was wondering exacly the same ahaha Even if the tool is super accurate i’m not sure two people will get the same measurement

lafaa123

43 points

3 days ago

lafaa123

43 points

3 days ago

I have the inside radius measurement device at work and you're correct, the tool fucking sucks. A huge problem is that the radius isn't linear, so as you get a shallower and shallower curve, your measurement gets less and less accurate.

[deleted]

26 points

3 days ago*

[deleted]

26 points

3 days ago*

[deleted]

ryangyangyang

12 points

3 days ago

You only do a sample size of three parts? Most of our customers wouldn accept anything less than 30 parts. To your point tho, GR&Rs tho are really excellent for understanding where your variation is coming from and if it’s acceptable!

Stromy42

3 points

2 days ago*

Repeatability and reproducibility doesn’t mean it’s right. It’s possible, and often happens, that measurement systems are repeatably and reproducibly wrong.

Edit: grammar

RainBoxRed

2 points

2 days ago

Accuracy vs precision.

mythosaz

27 points

3 days ago

mythosaz

27 points

3 days ago

You calibrate it by setting it on the floor and seeing if it measures the Earth correctly.

Arsanick

9 points

3 days ago

Arsanick

9 points

3 days ago

I'm sure it'll give you the right ballpark. Something like 5000km (+/- 100,000km)

yumyumgivemesome

5 points

3 days ago

Yeah, I didn’t see any way to ensure the measuring portion is parallel to the circle/arc. Being slightly askew would cause an inaccurate reading.

Lumpyyyyy

37 points

3 days ago

Lumpyyyyy

37 points

3 days ago

Now this is why I subscribe. I don’t even need it and I want one.

probablyjimmylam

26 points

3 days ago

I needed to measure the radius of an object for modeling and asked my teacher about it and she said it didn’t exist

sniper1rfa

34 points

3 days ago

Pro-tip: if you want to measure <thingy> just google <thingy> gauge. Engineers and scientists have measured virtually everything, and will generally sell you a doohickey to make it easier.

There are probably even tools out there for measuring your thingy, if that's you're thing.

ender4171

5 points

2 days ago

and will generally sell you a doohickey to make it easier

...for a price. Sometimes a jaw-dropping one, lol.

dartmaster666[S]

7 points

3 days ago

No, I'm pretty sure you could set them up to measure a curve and have it fail if it was out of tolerance.

anonymousguy9001

15 points

3 days ago

Puts tool flat on ground

"Checkmate globetards!"

This post is satire in case that's not clear...

S_m_r__ss_

144 points

3 days ago*

S_m_r__ss_

144 points

3 days ago*

How it works:

The length  of an arc depends on the radius of a circle and the central angle θ. We know that for the angle equal to 360 degrees (2π), the arc length is equal to circumference. Hence, as the proportion between angle and arc length is constant, we can say that:

L / θ = C / 2π

As circumference 

C = 2πr,

L / θ = 2πr / 2π

L / θ = r

We find out the arc length formula when multiplying this equation by θ:

L = r * θ

Hence, the arc length is equal to radius multiplied by the central angle  (in radians)

Source

-LEGO-

21 points

3 days ago

-LEGO-

21 points

3 days ago

notquark

3 points

3 days ago

notquark

3 points

3 days ago

Best use of that line................Including the one used in the show

ho_merjpimpson

2 points

2 days ago

except the dude isnt even right. that is one way to determine the radius, but its not at all how this tool does it.

sniper1rfa

33 points

3 days ago*

Arc length is not fixed in this gadget - you can see the little slides on the feet. The metal bow is only there for a visual reference (and for marking other objects).

This is simply defining a three point circle, with the linkage hooked up to produce a linear motion as it moves. The scale is arbitrary, and depends on the specific linkage being used.

crazedover

16 points

3 days ago

Here is proof you are right. The arc length cannot be fixed. The geometry does not allow it.

sniper1rfa

5 points

3 days ago

Thanks. Yeah, the bow would buckle, it would have to. How this isn't obvious is beyond me.

Even accounting for the slides, the bow will have a lobe between each mounting pin (because it has a constant section) and wouldn't be circular anyway, so it would make a crappy gauge.

dankmemeloader

2 points

3 days ago

The bow doesn't need to buckle so this doesn't prove anything. The design of the clamping arms is curved and could be angled so that they don't interfere with the bend of the bow. I do agree however that the arc length isn't fixed and that the key mechanism of measurement is identification of three points on a circle from a system of jointed lever arms that mark the distance from a pivot point. The mapping between radius and distance from the pivot point on the scale is nonlinear and is likely a sampling of uniform increments in radius.

Dick_Demon

9 points

3 days ago

Yes, you explained the basics of measuring arc length and radii. But this isn't how this contraption works at all.

Alright-At-Numbers

7 points

3 days ago

I don’t think arc length is fixed.

jrice39

2 points

3 days ago

jrice39

2 points

3 days ago

I read all of this in Sal Khan's voice.

SpecialPotion

2 points

2 days ago

Alright nerd, let's fight

I don't understand your magics, bur we're fighting

museolini

11 points

3 days ago

museolini

11 points

3 days ago

Routine_Left

2 points

3 days ago

Aaah, so you use it to find the radius of a circle. Now I get it. I was wondering what was it used for.

Horton1975

16 points

3 days ago

*Gauge

dnemets

3 points

3 days ago

dnemets

3 points

3 days ago

^ doing the lord's work

NSWthrowaway86

21 points

3 days ago

Speaking as an engineer, this would be susceptible to a high error variance due to the human element. Speaking as a nerdy guy, this is awesome - it's like the power of geometry incarnated.

Dyspaereunia

4 points

3 days ago

This looks like a less roundabout way of measuring.

SecularPaladin

6 points

3 days ago

Right? As a machinist I can get you that radius to within three decimals.

SecularPaladin

4 points

3 days ago

With a simple caliper, I should have said.

TheRedViking

2 points

3 days ago

Can you explain how?

SecularPaladin

5 points

3 days ago

Measure diameter, divide by two.

TheRedViking

4 points

3 days ago

Only works if you have most of the circle

SecularPaladin

7 points

3 days ago

If you measure a chord across the arc, and the rise above it, you can solve for the radius with this formula:

R=( b2 + a2 )/2a

Where a and b are the respective short and long sides of either right triangle formed from the chord and rise.

vavavoomvoom9

10 points

3 days ago

This is some trigonometry stuff that I remember none of.

mr_blanket

6 points

3 days ago

SIN COS TAN

the three most frightening buttons in existence

SecularPaladin

2 points

2 days ago

SOH CAH TOA and you're good to go!

[deleted]

56 points

3 days ago*

[deleted]

56 points

3 days ago*

[deleted]

neon_overload

106 points

3 days ago*

It's measuring radius by measuring the curvature of the edge.

Imagine the curve it's measuring is part of an invisible circle where that curve fits on the perimeter of that circle. It measures the radius of that invisible circle. The markings on the device have been pre-calculated to convert that curvature to a radius.

This allows you to get the radius of a curve even when there is no complete circle.

therealbrosefstalin

27 points

3 days ago

Just to add on, that “invisible circle” is actually called an osculating circle in differential geometry. The radius of that circle at a given point is known as the radius of curvature.

The gauge uses this concept to calculate the radius/diameter of cylindrical and circular objects.

ILikeSugarCookies

3 points

3 days ago

Fuckin NERDS!

ima420r

6 points

3 days ago

ima420r

6 points

3 days ago

So by measuring a curve you can know it's circumference if it is a perfect circle, thus getting it's radius? That makes sense. A circle that has an inch circumference is going to have a tighter(?) radius than one that has a foot circumference.

neon_overload

12 points

3 days ago

Yes that's it. Curves don't all fit on circles because they may be elliptical or parabolic or just not particularly regular, but any chosen point on the curve still has a radius which corresponds to the radius of the imaginary circle whose edge has the same curvature as that part of the curve.

GoatSaysYes

6 points

3 days ago

This is how all curves/arcs work. Once you do any CAD work circles just click in your head.

sniper1rfa

3 points

3 days ago

So by measuring a curve you can know it's circumference if it is a perfect circle

Keep in mind that this tool does not tell you whether the arc is a circle. It only tells you the radius that the circle would be if it was a circle. You need prior knowledge or a different set of tools for this to be effective.

the_tza

18 points

3 days ago

the_tza

18 points

3 days ago

I’m sure you could determine several qualities of a circle with this device, radius included.

PaulAspie

10 points

3 days ago

PaulAspie

10 points

3 days ago

Exactly. If it is a circle, once you know one thing, most of the rest are related by simple formulas.

Freaky_Freddy

6 points

3 days ago

If you know 3 points in a circle (or arc) you can know its diameter/radius.

Its what that tool does. It has 1 fixed point in the middle and 2 on the sides that move (the tool also has a band that goes through those 3 points to help with the measurement but technically its not needed)

The people that invented that tool calculated the ratio between the movement of the two front arms and the 2 back ones that are connected to the lever and how they relate to a circles diameter and printed the scale accordingly

Probably not very accurate if you're looking for high tolerances, but for most workshops its quick and good enough

Cr3X1eUZ

4 points

3 days ago

Cr3X1eUZ

4 points

3 days ago

If you know one you can calculate the other.

theexpertgamer1

5 points

3 days ago

It literally shows in the video “radius in inches.” It indirectly measures the radius by directly measuring the arc.

GodzillaLikesBoobs

3 points

3 days ago

sure it does.

arclength / inner angle = circumference / 2pi = 2piR / 2pi = R

arclength is usually L or s depending on contect, angle T (for theta).

L/T = R or L = TR.

the magic happens when any one variable is fixed. L is fixed, obviously in the video because its the metal band flexing that never changes length. therefore as the band flexes inwards, L = TR creates a relationship where the angle and the radius are inversely proportional. you only need to know one value, say the angle (as is the case in the video) and the radius is forced.

laughingfuzz1138

5 points

3 days ago

Your confidence is sorely misplaced.

It does measure the radius, you can see as much in the video as the measurement it gives is labelled as radius, in inches on one side and millimeters on the other.

This tool has no way to measure degrees of arc. This tool is completely agnostic to whether you're even holding it up to a circular arc or a complete circle.

It's called in outside radius gauge because it measure a radius from the outside of the arc. To measure it from the inside, the arms would have to bend to opposite way. Such a tool also exists, called an "inside radius gauge". Both tools are used to measure the radius of an arc or a circle.

It doesn't "measure the arc in radii", because radii isn't a unit of measure, it's the plural of radius. You're probably thinking of *radians*, which is a unit of measure of angles. While relevant to arcs, it wouldn't be measured directly with this tool.

sniper1rfa

2 points

3 days ago

This tool is completely agnostic to whether you're even holding it up to a circular arc or a complete circle.

or even a circular arc. The bow is a visual reference so you don't accidentally try to measure something egregiously non-circular.

jetfuelsake

2 points

3 days ago

If you know a circle’s curvature then you know it’s radius.

nrzki

3 points

3 days ago

nrzki

3 points

3 days ago

Is there an equivalent tool to measure inner radius as well?

WellGradedGravel

5 points

3 days ago

Yes, they are called inside radius gauges. They look very similar.

[deleted]

4 points

3 days ago

[deleted]

4 points

3 days ago

[removed]

TiltnJimmy

2 points

3 days ago

My guess is to place the piece on a worktable. Then clamp 90 degree stops (I think 9 of them) to the inside radius of the pipe.

s_t665

3 points

3 days ago

s_t665

3 points

3 days ago

HammerSchwing

2 points

3 days ago

How small does it measure you think?

TheWrongFusebox

11 points

3 days ago

Not that small, petal.

TiltnJimmy

3 points

3 days ago

150 mm from the looks of it.

HammerSchwing

1 points

3 days ago

Hmmm. Not small enough.

TiltnJimmy

2 points

3 days ago

precision calipers, that's what your looking for. I'd let you use mine but, ye know

AngrieShorty

2 points

3 days ago

No sir you've got it all wrong. That is a crossbow

nelskaisabeast

2 points

3 days ago

top post typo.

ktka

2 points

3 days ago

ktka

2 points

3 days ago

Technical name: Girthtron.

1Plz-Easy-Way-Star

2 points

3 days ago

Can you calculate Earth curve with that thing ?

Floydope

2 points

3 days ago

Floydope

2 points

3 days ago

Radius? Really?

webesteadymobbin420

2 points

3 days ago

*gauge

gSalmonb

2 points

3 days ago

gSalmonb

2 points

3 days ago

Please correct me, because I am probably wrong. I thought the radius was just half of the distance across the circle. Couldnt you just measure across the circle with a normal ruler, and divide by 2?

xrumrunnrx

2 points

2 days ago

Dave Thomas: Alright, Space Ghost, how thick is your neck?

Space Ghost: I'll ask the questions, Dave. How thick is my neck? It's 48 inches.

Dave Thomas: That's a decent sized neck.

Space Ghost: Radius, Dave.

Dave Thomas: 48 inch radius.

Space Ghost: Radius.

Dave Thomas: How do you measure it, with a straightened coat hanger or...

Space Ghost: I just cut my head off and count the rings on my esophagus.

Dave Thomas: Fair enough.

TyphoidGarry

2 points

2 days ago

I have zero need for this and I still want one.

wlbrndl

4 points

3 days ago

wlbrndl

4 points

3 days ago

that’s hot

2much2remember

2 points

3 days ago

I prefer using Trig, keeps me on my toes.

retailguy_again

1 points

3 days ago

That's awesome! I always wondered how radius was measured--thanks! Yeah, now I want one too...

The_cynical_panther

2 points

3 days ago*

I work in an industry with a lot of precision tubular parts and haven’t actually seen one of these before. At my facility, Quality Control has a few micrometer sets to measure outer and inner diameters of parts. I’m not sure what they use for the really big stuff (>24”), maybe the big digital caliper. We also have a couple of Pi Tapes.

E: just realized you said radius specifically. They have a special caliper for measuring radius, as well as some radius gauges. Probably some other clever stuff too.

sniper1rfa

2 points

3 days ago

that only works if you have more than 180* of arc.

Those_arent_PILL0WS

1 points

3 days ago

Just needs attachments for pencils in the arms to draw the perfect circle.

[deleted]

1 points

3 days ago

[deleted]

1 points

3 days ago

[removed]

[deleted]

2 points

3 days ago

[deleted]

2 points

3 days ago

[removed]

ucrbuffalo

1 points

3 days ago

And how do you practically use that measurement?

5lack5

3 points

3 days ago

5lack5

3 points

3 days ago

Imagine you need to replicate a section of handrail, but don't know how far to bend it to get the right shape. This tool will give you the info you need to do that, especially if you need repeatability

lafaa123

4 points

3 days ago

lafaa123

4 points

3 days ago

I actually have this exact tool at my job for the exact scenario you're describing (we dont copy, we design and create, sometimes we need curved railings)

I don't trust the tool farther than I can throw it. it sucks a whole lot.

TMKIIISSSTTTIIILLL

2 points

3 days ago

We bought the inside and outside gauges when we had to make some guarding for an old machine. I’d rather use cardboard and string than these. I had some flanges laser cut based on what I measured, and they were off by a mile.

HeioFish

2 points

3 days ago*

Also would probably be great for stickler-architects. Some of them want proof from the trades that everything has been done exactly as they’ve instructed. This tool would be invaluable for proving that that “funny” looking radius was exactly what they spec’ed

Judas_Feast

1 points

3 days ago

Neat

jomarez

1 points

3 days ago

jomarez

1 points

3 days ago

Now try it on the ground. Checkmate round earthers.

mutsuto

1 points

3 days ago

mutsuto

1 points

3 days ago

sgpk242

1 points

3 days ago

sgpk242

1 points

3 days ago

Flat earthers would love this

Ok_Stop_5867

1 points

3 days ago

Usually I've had to do math for that - cool device ..well done!

Willygolightly

1 points

3 days ago

I really thought this was a crossbow on my archery sub. Really cool.

jocularsplash02

1 points

3 days ago

How long until flat earthers start bringing these things to their displays so they can measure the ground and go "sEe, It DoEsN't HaVe A cUrViTuRe"?

I_have_questions_ppl

1 points

3 days ago

Does Adam Savage know about this?

Warm_Zombie

1 points

3 days ago

i love this sub

Uhtred_War_Lord

1 points

3 days ago

That's awesome, i wish o had a job that needs this Tool.

chunkboslicemen

1 points

3 days ago

Anyone else disappointed this is NOT a crossbow?

Methadras

1 points

3 days ago

I need this in my life right now.

theottomaddox

1 points

3 days ago

When I win the lottery and that show comes to see the house I built it will have one room with the walls covered in all the specialized tools I've seen in the last couple of years here.