How to measure accurately with a dial indicator
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- เผยแพร่เมื่อ 20 ก.ค. 2015
- Dial indicators are a must have for most shops. How you position the probe will directly relate to how accurate your measurements will be. Take a look at what happen to the accuracy when the probe is positioned at different angles and when you add an extended probe.
www.subtool.com
I'm not ashamed to say that the youtube machining community has taught me so much about the trade... and I'm a retired shop teacher! Thanks for your excellent videos.
I have long recognized that the parallel position of the indicator end is very important for the measurement, but many colleagues laughed at me. Thank you!
Thank you for watching.
I always thought the angle was an issue but never thought to try this simple test. Thanks for taking time to share your knowledge I appreciate it immensely .
These demonstrations keep bringing back my tool making days. Great videos. Thanks Don.
I knew about the sine error, but tips wearing out is something I never thought about. Thanks, Don!
Yours measuring shows a lots of fundamental skills, this helps a lot on my job, much appreciate.
Don, Just imagine the folks that you lent your expertise and I'm not just talking about the youtube aspect, but all that you have brought along in your career. Kudos to you!
Thank you for watching!
Had to quit tool grinding 8 years ago bad heart. Enjoy your videos
Thank you, take care of yourself!
Thank you very much sir. I really appreciate how you have taught me about, when the indicator stem has been lengthened, it causes inaccuracies. I didn’t know about that. Thanks again.
Great demonstration it's good to see how much of a difference that made.
I just got my first one today. Thanks for another good video.
Great job, Don. Many thanks.
I always tend to think of those type gauges as comparators more so than measuring devices. the same errors occur if a standard dial indicator is not exactly perpendicular to the work as well.
Correct. Because they are used as comparators more than anything else.
Zeroing in the indicator both prevents math errors and ensures that when the part(s) such as gears are returned to the starting position during a backlash check they're being returned to true "zero" and you're just measuring backlash and not inadvertently including/measuring some actual rotational movement. As for using a dial indicator to measure "thickness" or "height" or whatever it is you're attempting to "measure" with those small "blocks" on top of that larger piece of material you're moving laterally under the meter "arm", the length of that "arm" shouldn't affect "accuracy" at all. It's reading "half as much" (parallax in the video view notwithstanding it still looks closer to "1" than "0" because as the end of the "lever" gets farther from the fulcrum, the end of the lever has to move farther to achieve the same amount of movement at the "short end" of that lever/fulcrum arrangement. You're changing the "rocker arm ratio" of the indicator/arm set-up and the "accuracy" of the indicator shouldn't be and isn't being affected at all beyond the fact that its not graduated correctly and PRECISE enough to measure ACCURATE "one half" of 1 unit. You're guessing at the actual "measurement" the same way using a non-Vernier micrometer 0-1" micrometer results in guessing at ten-thousandths. There's also a "tolerance stackup" situation that occurs when you "stack" items to be "measured" like that. The two "blocks" may be exactly one thousandth different in thickness when measured by themselves but when you place them on top of that other piece of material and are sliding the "assembly" side to side and in particular are letting the taller "block" shove the indicator "tip" upward and also jar the indicator assembly/setup slightly sideways instead of lifting the "tip" up coming off the first "block" and then setting it back down on the second block gently you're creating error or at least the potential for that error. And when a dial indicator is used to measure the "height" of something a conventional dial indicator with a "vertical" plunger installed in a "sled gauge" should be used. Dial indicators are at their most accurate and precise when measuring MOVEMENT in a setup like you've got there. When used to measure "height" the indicator needs to be perpendicular and vertical to the surface(s) being measured and is never "shoved" from a "high step" to a "low step" unless it has a rounded tip with plenty of radius to "roll" onto the higher step without the plunger being shoved sideways. Proper demonstration/use of a dial indicator to measure "height" would be with a sled gauge measuring cylinder liner protrusion above a diesel engine block "deck" or valve face protrusion above the "fire deck" of a diesel engine cylinder head.
That's a nice looking vernier height gauge.
always love your informaiton and the way your relay it....cheers...
Nice true facts... good reminder
Sir what is the instrument near by you 2 feet long and one rotating head on the top.
Can you tell and also show the use.
Accurately measuring small dimensions is one thing. But how do you measure long dimensions? I need to measure 31" +/- .005. I don't have a caliper that big. Any suggestions appreciated.
Great video thank you
Very informative video. Clear and concise.
Glad you enjoyed it!
Please make more calibration videos
im trying to use one for leveling a surface but i always get different results...ite pretty frustrating
Dude your video is awesome
Glad you think so!
one thing to be noted also is that the temperature also affects the measurement...I work in a temp controlled environment and everything I measured i had to let it soak overnight... usually around 24 hours
You are correct.
I need to get back into that type of job, it was fun and I learned more and more everyday while I was there, its a great career. I had to stop working at the Calibration industry I was at because my girlfriend had cancer and I had to ensure she got to her appointments weekly
Groovy music in the beginning :)
I heard about trig... but I never seen it.
Brilliant, thank you
You're very welcome!
Thank you more...reaaly helps me to do my task😍😍😍😍
Thank you for watching!
Is the table where the dial indicator needs to be clean? I had the time of my life yesterday trying to get to to be on zero, chasing my tail, but my vise was over tighten one of the bolts. That did not help. Run in frustration and got a headache 🤕. Any thoughts on this.?
Che as your avatar? Communism is a loser cult.
can you use a indicator with a broken stylis
Johnny Smith said:
"can you use a indicator with a broken stylis"
It would be insane to do so.
This is really daunting now... I wanted to buy a test indicator to surface a flat surface, but after watching this it seems I need to carefully choose the right test indicator else I'll be wasting time, energy and money. Can anyone recommend which is the best test indicator for the task of inspecting flatness, Parnellism and squareness of a granite surface?
You all eat a lot it's always lunch around there 😀🍔
jason knight Keeps us energized. Thanks for watching.
I love how he smile when the end of this video..
What you are describing is called cosine error and you're not 100% correct Don. Some manufactures calibrate their indicators to zero at a specific angle not flat an parallel as you describe. Interapid for instance calibrates their indicators at 12 degrees. Thanks for all of your videos Don we greatly appreciate them. Im two years into my toolmakers apprenticeship and greatly enjoy you sharing your wealth of knowledge. God bless. Ohh and im curious if suburban tool offers a matched set of 4 123 blocks. I only see 2 online. Thanks
SkHiPiY If you look at the tolerances of our 123 blocks, you will see that you can buy individual blocks or 2 sets and stay within a couple of tenths without the extra cost of requesting 4 matched blocks. It all depends on how close you need them to be. The blocks with holes that we make here can also be bolted together. www.subtool.com/st/b123_precision_tri-blocks.html
SkHiPiY Yes you are correct, i have a mitutoyo clock that must be set at 20 degrees for true reading rather than referencing.
SkHiPiY Yes you are correct, i have a mitutoyo clock that must be set at 20 degrees for true reading rather than referencing.
A good example that goes to show you should read the instructions, they may well know more about their kit than you do.
cosine error
Wohooo!!!! Lunch😂😂😂😂
I never use the indicator's marks to measure. They're there as a guide only. Like Don says there are too many variables that effect accuracy. When an indicator is attached to a measuring device like a height gage, you should use that device to make the actual measurement.
Except a height gage usually cannot measure in .0001 increments, except the very high-end ones, which no one can afford.
nice guy
I have a noobie question. It's a real situation at my work. I have a cylindrical piece (about 10" diameter x 10" height) which I rotate in a surface plate against two guide poles separated about 120 degrees. I have two dial indicators: one is in the middle of the two guides and one is exactly above one of the guides almost in the cylinder's tip. What's exactly each dial indicators is measuring (eg eccentricity, circularity etc?) Thank you in advance.
You explain to keep the Indicator horizontal to avoid a false reading, you did not explain what's "causing" the false reading? 90° or 45° What's causing the needle to go up and down? if both surfaces are equal at 90° If anybody knows the answer please leave a comment below. But if you're making your best guess or you're pretty sure... please don't
Well that y u need a carbide tip or I call ruby tip that well never wear..look like a cheap test indicator...
4:50 I'm suddenly peckish for some reason.....
Your indicator is bad
are you sure ?