Measuring Angles in the Machine Shop!

After a Richard King hand scraping class, I wanted to check our set of V blocks to see how accurate they are - so let's discuss different metrology and measuring techniques to measure angles.
iPhone Gage Block App: bit.ly/2rMRjuI
Surface Gage (Amazon): amzn.to/2tdntS1
Surface Gage (eBay): ebay.to/2ssbSyw 5 Reasons to Use a Fixture Plate on Your CNC Machine: bit.ly/3sNA4uH

[@ROBRENZ]

Thanks for the shout out John! I was cringing when you were using that unground stone on those parts ;-) ATB, Robin

[@tomherd4179]

I have to add this comment; I did get a lot out of what you said, but as I am 72 and just trying to learn Fusion by myself I really found your Fusion illustrations very, very interesting. I have just taken notes of your Fusion operations and duplicated them. Fusion simply amazes me! Thanks :-D

[@Gary.7920]

Outstanding Video John. Thank You Gary 74-Year-Old Home Shop Machinist

[@Tinman3750]

I've used the "photo method" many times for 3D printed parts that don't require a crazy amount of precision. Typically, if the part is small and flat enough, I'll just stick it on the office scanner to avoid any distortion along the profile I want to import into software.

[@patricksullivan9951]

John, nicely done, Tom Lipton got me interested in metrology and measuring techniques, and now you are adding your take & ideas on the subject. Nice! Looking forward to saying hi at the Bash!!

[@toddk.5873]

You came along way John. Good job. I started watching your videos about 6 years ago looking up info on an Atlas horizontal mill. Since then I experimented with Arduino, which led me into building a cnc x2 mini mill. I recently bought a surface plate & plan to scrape it a little truer. We seem to paralleling on learning a little though you are running rings around me. Keep up the good work & thanks for sharing.

[@Thunderbelch]

Handy tip, you can calculate the arcsin in the default Windows calculator too; just hit the Inv button (top left) and sin becomes arcsin (sin^-1).

[@anthonyvancampen6729]

John, I'm a little late to this party but a good approximation from the days of slide rule calculations is to substitute Tangent for Sine for angles less than 6 degrees. Your example using Fusion shows how well that approximation works. Thank you for an excellent video and for showing so many ways to check the accuracy of parts and tooling.

[@TheWidgetWorks]

That was an excellent intro to how to measure well. I have made very expensive part for very critical processes from just a cell phone picture and a couple tape measure measurements and you would be shocked how close you can get (easy to be within .005" or less if you can get the tape measure and the part in the same plane!).

[@SolidRockMachineShopInc]

Hi John, What a coincidence, last week I did a video on freshening up my 10" sine plate. We plan on doing a video this week grinding a friends V block using the sine plate. We did an earlier video grinding my friends 2.5*5*6 block square within .0001" in 6" Steve

[@mikstratok]

For those of us with no surface plates, and expensive gauge blocks ... I like to use a digital dial indicator in the mill to measure the drop on the angled surface, one of the measurements will only be as good as the DRO, and it presupposes that the vise is perfectly flat, or that you set a bottom surface that is or can be indicated (for example a clamped parallel on the vise) this method is usually good enough for the girls I go out with ...

[@wojtczak1984]

absolutely right. because it is a "right" angle. I think of it as up 1 over 1 gets you 45deg. great vid by the way I nerd out over this stuff and don't know why.

[@funone8716]

I predict within 6 months there will be a CMM and a climate controlled metrology lab at Saunders Machine Works!

[@edrees3874]

heh.

[@cylosgarage]

I bet Mr. Wizard will beat him to it

[@2222e100]

Are you hinting at something ed?

[@kmcwhq]

Easton Bednarek Ya stop spreading rumors Ed......lol

[@Bitfrogess]

Its one of those things you will ask yourself why you didn't buy it sooner. Our CMM saves us so much time!

[@stevecanny1583]

Nice video John! I wondered what those pins were for on my surface gage, I put that little tidbit to use this very night :) Also the bit on sneaking up from one side on the fine adjust; that makes perfect sense now that you mention it, but I hadn't known that one before :) On the CAD results, the sine bar makes up the hypotenuse of the right triangle, the 3.53 is the vertical leg. Since it's 45 degrees, both legs are the same. So the result you got is right on. When you make your blocks, good to grind them side-by-side in the same setup(s). That way they should be pretty-darned-close to matched. On the picture method, I expect that's a very handy way to make some rough estimates for hard-to-access parts. One thing to keep in mind there is that it is very sensitive to the camera being perpendicular to the angle you're trying to measure; a couple degrees off "straight in" on your camera shot will lead to similar errors in the angle measured. Probably tough to do consistently hand-held, but good to have in the repertoire for hairy situations. I'll look forward with great interest to any additional metrology videos you produce :)

[@inuyashacoolieo]

I always just took the pins that came with the height gage and tossed them in a drawer. Never thought to use them like that. Now I have to go diggin' for some new pins haha.

[@qwertyyuiop12345678]

First comment yew, hello from down under. Love your stuff - I have been inspired by your attitude and work. Started a little hobby business making GoPro trays for underwater video/photography, my next product will be underwater lights.

[@TheEppicJr]

it is a 45-45-90 triangle, it wouldn't happen anywhere else

[@roylucas1027]

Thanks for great video.

[@willfrancis858]

To get rid of that constant noise in the background run your audio through Audacity and use the noise reduction filter. Works beautifully and completely free!

[@ajtrvll]

Great video!... I like your showcase of multiple techniques, especially with Fusion 360 illustrations. If your looking for video ideas: Test the accuracy and the precision of angles measured with an iPhone (or other). Most spirit level apps display to a tenth of a degree and they can be calibrated... could make for some interesting setups and discussions.

[@airbrushsavvy1750]

John, I use software called polyworks and the hardware Romer. to do some pretty tricky stuff. I think this would fit in beautifully with your operation!

[@bcbloc02]

I searched online for info on temperature compensation of your lh600 height gage but couldn't find much. All I could find was that it appears to be manually set. To me that indicates that it needs to be calibrated everytime you use it since you aren't climate controlled. I think it is likely that your gage block stack was correct and your high end stand was reading the incorrect value because the temperature the measurement was taken at was not the standard it was calibrated for. It would only take a 5deg temp variance to account for the 2 tenths. I am curious about how that LH600 deals with temperature for accuracy. Time to read the book and get back to us! :-)

[@exactengineeringllc5254]

agreed. the gage blocks are the standard. height is gage not a standard and should be qualified to a standard, not the other way around.

[@murrayedington]

Your granite surface plate isn't completely flat, as they have natural craters in the surface. You can see that from a distance. So when you zero your height gauge with a ball probe, you need to ensure it isn't dropping into one of the craters. If you did, you'd find your gauge blocks appearing to be too long - as you found. So you'd need to either check in several places or (better) use a known good gauge block. You can check that with a good quality micrometer.

[@ricardrinaldo4791]

06:20 Awesome!!! Wasn´t aware of that

[@Elitesniper257]

1:07 "We'll just stone these" 😂 Sorry, didn't have anything too productive to say. Great video btw :)

[@roderickwhitehead]

When using a photograph, watch out for parallax errors. I am sure that is why you got 90.7º... because the lens was lower than the vee so the perspective was making the angle appear more obtuse. Also, it's a bit older, but I have used Autodesk 123D for civil design when I did not have the budget for surveying. I would bring in multiple photographs to create a 3D model, and then export meshed out surfaces to bring them into AutoCAD Civil 3D. I then have something to evaluate mass quantities. I would imagine this could be of use for a machine shop environment too, especially if you are running CNC.

[@Thunderbelch]

There are actually precision applications for cameras in the metrology lab. I'm busy scratch building an autocollimator using a camera sensor that will give me 0.231 arcsec resolution. That's quite a bit better than what I can achieve with just optics and mechanics.

[@yadokingau]

I'd love to know more about that autocollimator. Are you likely to post about it anywhere?

[@Thunderbelch]

Once I have it at the point where I'm confident in the results, I'll definitely post it. Right now I'm deciding between a youtube video and either madmodder or practicalmachinist...

[@highstreetkillers4377]

Optical comparator, is proven and very accurate.This guy even has one but clearly doesn't know how

[@JohnHolmestheSecond]

good on ya lad. precision is important.

[@timbufordbriggs]

Great channel! Curious to know if you measured the sine bar to see how close it was to 5 inches.

[@highstreetkillers4377]

Exactly. The least amount of variables is the most accurate.He has an optical comparator, thats the best for measuring

[@DrFiero]

Can you expand on the photo route? Simple example - Say you had a gasket for something and wanted to make a spacer plate. You could shoot the gasket, make a 2D drawing, then just mill it out.

[@Sketch1994]

I've messed with measuring from photos a little and you must take a shot for each small area you're going to measure while keeping the lens plane as parallel to the surface you want to measure and the center of the lens exactly over the vertical axis of datum point(like the inside of a corner). The further away from this axis everything get's distorted and also you want to check out image compression formats cause especially jpeg distorts dimensions by a lot(I noticed that when going from .srw to .jpeg things ended up in different places just by eye). Finally there are special camera lenses in the multi thousand dollar price range that compensate for tilting in order to imitate an orthographic view.

[@highstreetkillers4377]

I built an assembly machine 15 years ago that had built in cameras to measure, not amateur. It works if you have a master gauge picture first, then camera cant move and parts in a jig to keep it in the same spot. He has an optical comparator he should be using

[@beachboardfan9544]

So John, this comment ( 3:09 ) made me wonder, how do you set a shop tolerance? Like when specking jobs, what tolerance do you tell customers you are capable of and how do you decide that? Cant imagine you are doing work with millionths of accuracy...

[@occamssawzall3486]

Only measures the V block in one direction. Left to right. Measure front to back and see if it's off. Might be 45 deg in a linear direction. But the two planes may not be 45.

[@ecr125x]

Occams Sawzall was thinking the same or that the gauge rod isn't perfect.. I wonder if it's the same "side" on both v blocks of same side of the rod .. none the less it was a good video

[@kathyquinlan5922]

My bet would be that the Gauge pin is not the same diameter both ends, as it would account for the same difference on both blocks.

[@vilts]

That was my first thought as well :)

[@Cinnabuns2009]

Or the V blocks where made in the same shite workstation in China and run out the same because of that. No way that gauge pin is .001" smaller on one end.

[@CJ-ty8sv]

Cinnabuns2009, gauge pin (if Chinese) could have taper from a shit workstation just like you said for the V blocks. I've seen cheap shit gauge pins have more then 1 thou difference between the ends...... I do agree thought, the grinder that was used to grind the blocks could have easily had a taper in the rails which inadvertently put a taper in the blocks, or crap under the fixture used to bold them, etc.... But all the possibilities would apply too to the manufacturing of the pins also... Without measuring, we are all just speculating at this point.

[@johnm2369]

Im new at my shop and saw what one degree on a 3' diameter with a canned cycle off meant. About 1/2" ..

[@auhopu]

45 deg on a right triangle means the third angle is 45 deg too. Therefore the triangle is isosceles.

[@ke6bnl]

FUN video

[@tomaszstaron1408]

14:49 "they don't have to be hi end and expensive" said a guy who have mitutoyo high gauge for almost 10k$ (which is almost the same price as pcnc1100) ;))) I realy like Mitutoyo's staff, like Abom79 like Starrett ;) But realy like also old Polish mesurement tools: VIS, FWP, and some russian made ;))

[@highstreetkillers4377]

Lol Polish, haha.

[@urgamecshk]

It's 1:1 because it's based off a 45* angle ;)

[@chiefmachining7972]

beat me to it

[@billanderson5246]

A great project would be to build a Kingway Tool and then follow up would be to show different ways to use it

[@celexalexandersson]

Hi from Sweden! Around 12 mins in you changed the side on the gaugeblock and it was off by around 2-3 thou' and you resetted it to zero. Allthou its not the main thing in the video and the V-block isnt the sharpest tool in your box. the next time you will regrind the surface on those. Will you make it even on both sides?? So when you put it up on 45 degrees and change side it will with your Mitutoyo it will not change 2-3 thou' between each side? Great show btw..

[@kalabrushka]

I think scanning the v-block on your printer would deliver a very accurate image to use in F360

[@highstreetkillers4377]

Its cool he thinks outside the box but anyone doing that where i've been would just be fired

[@wojtczak1984]

yeah I work at a place that has 4 CMM's now. I think our quality inspectors are addicted to them.

[@CatNolara]

The way you checked it in fusion isn't right, when you go to 45° and then go back the 44.9...° the gap isn't angled anymore. If you begin the angles both at the base line and measure at the other end you should get different readings. It doesn't show with these small deviations but would make a huge difference when the angle difference gets bigger.

[@GainamilitaryFitness]

How can i calibrate a sine. Bar ?

[@highstreetkillers4377]

You have an optical comparator. It doesn't get more accurate

[@bzaz_3158]

(sin(x))/x=1 when x is small

[@LeRoyLincoln]

Wolframa Alpha (www.wolframalpha.com/) is an excellent online solver, said the former math teacher!

[@machinist7230]

best thing to clean surface plates with is alcohol, as it leaves no residue, unlike winded..

[@jbbauer0]

yup just put some in a spray bottle

[@highstreetkillers4377]

Kerosene

[@LeptonHeavy]

You may be running into the small angle approximation For very small angles sin x ~= x en.m.wikipedia.org/wiki/Small-angle_approximation

[@sethmadore4127]

John, just buy a CMM ;)

[@highstreetkillers4377]

Waste of money, just learn how to use your comparator.

[@jacobor79]

Mou wouldn't have to mess all with that bullshit with a good CMM

[@ajtrvll]

Reading the comments, how much accuracy is too much accuracy, practically speaking in a purely business job-shop setting (no scraping, no YT creating, etc.)? For a machine shop like yours, do you need to measure parts to within 0.00005 in. (half a tenth)? If your machine tools can reliably deliver accuracy of ± 0.001 in. (one thou), I would imagine your metrology "tool box" should reliably measure within ± 0.0005 in. (half a thou), no more no less... How much can this factor of 10 of extra accuracy affect profitability and shop efficiency?

[@sethhummel7416]

Two words: Optical Comparator

[@adamgalowitz1129]

Seth Hummel 17:47 in the background

[@sethhummel7416]

Adam Galowitz but it wasnt used :(

[@PaulSteMarie]

Seth Hummel Effectively, that's exactly what he did with the cell phone. The cell phone camera probably has more distortion than an optical comparator, but still it's the same principle.

[@highstreetkillers4377]

Similar yes, but comparator can be better than a cmm if you know how to use it properly. My first job 18 years ago was QC on a comparator for bullets. Back then it had a refraction option that makes it look like a picture on the screen. I could see my finger and measure my finger prints or splinter size, haha

[@JeffCowan]

The RobRenz video is excellent: kzbin.info/www/bejne/eoeviaanbNWcb7s

[@highstreetkillers4377]

If youre worried about measurement under 1 thou you should be using Metric. Smaller increments are more accurate. 0.001 " is equal to 0.0254 mm. Much better, US is behind

[@rmkscrambler]

Funny you think the US is behind. Yet you failed to use metric properly. The Metric system is a prefix "decimal" devised as a replacement for the numerical decimal. So 0.001" = 2cm 5mm 4um The system really is so ludicrous it has never been adapted according to design but rather blended with US customary to make it some what use able. Also if two things are "equal" one can't be more accurate. What's even more hilarious about your comment is you suggest using metric in a video that is about measuring angles. Hint Hint Angles don't exist in the metric system.

[@highstreetkillers4377]

rmkscrambler you just spat out a whole bunch of dumb. 0.001" isn't equal to 2cm. Not even close.

[@rmkscrambler]

That's what happens with the metric system constant error. You've either got to memorizing prefixes to scale a single unit. Or just revert back to us customary/imperial decimal system as most have done. Does 254 um sound better? Or if you actually consider a mm a unit which it's not. 2cmm 5mmm 4umm.

[@CmdrRoot]

interesting video, but the background noise makes it hard to watch

[@attainableapex]

Dude can you just start using solidworks. I think it's time for you to step it up