Cheap Way to Measure Very Accurately!
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- čas přidán 27. 10. 2015
- Micrometers and calipers are great, but let's measure a better way using a dial indicator and height gages!
Gage Blocks: amzn.to/1GKIjNs or ebay.to/1kTDeZu
Test Indicator: ebay.to/1HcBIGt
Surface Gage: ebay.to/1O8zNKV
Digital Micrometer: ebay.to/1PVgJPG
Mitutoyo Calipers: amzn.to/1M2Atz4
Surface Plate (Free S&H!): amzn.to/1kcdlmT
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Hi John. I will just share a couple of tips with you. You can wipe your gauge blocks on your wrist before joining them. The small amount of oil from your wrist helps them join. Also you should twist them from 90 degrees to parallel to join them. When using a DTI for measuring. It needs to be as close as possible to the base plate. Otherwise any crap on the table or deviation on the surface plate will give you false readings. Keep up the great videos!
I was gonna suggest the same bit about twisting to wring them. Slide them together perpendicular to each other, making a sort of plus-sign, applying a small amount of pressure toward each other, then twist them 90° once the plus sign is symmetric. You should find it very difficult to finish the twist.
Also keep in mind the ambient temp when using gages
best to use them in a temp controlled room so you eliminate error due to expansion/shrinkage of the gage and workpiece
We made height gages like those in school, milled them our roughly and then hardened them and after that we ground them down with an old jakobsen hydraulic precision surface grinder.
Came out top notch quality and stuck together as the ones you show!
Great video John! I like these short videos with a specific tip, particularly directed more toward the home and small shop. The fact that you can get great results with inexpensive equipment is a big deal.
i used that method a lot!.. use to be a tool and die Maker. few jobs we did was custom hight guages, and thats how i checked my accuracy after surface grinding them. some times micrometers do cover up major dips in the work piece. keep up the awesome videos
good basic stuff but keep the rod holding the indicator shorter and up closer to the base. also you set the indicator and moved the blocks under it correctly to make sure it would repeat but you did not reset the indicator and accepted a few tenths off--not good--reset it or remember where the needle was. the other thing was then you immediately grabbed the base and were moving the indicator all over the place.. sometimes it has to be moved but the proper procedure just for future reference is the part is moved--not the indicator after setting. also a tip. Drill the surface plate with a common mason carbide drill and install a 3/4 post held on with 1/4-20 from below--yes cbore with a bigger drill. Then make a basic indicator holder with a reamed 3/4 hole.. also on that 3/4 shaft sticking up--make a plate with a setscrew that has a precision big radius out about 2 or 3 inches or so for squaring up.. I will upload a video doing that so you know what I am talking about.
THIS type of stuff is PRICELESS information. I love how you lay it down and say you don't need 1000's of $ to do something like this. I agree. there is a point of diminishing returns on everything, and a a lot of times the cheaper chinese/off-brand stuff WILL do just fine for 95% of applications. i mean, most of us are probably still on X2, X3, BF20 mills. I'm still just learning to use my X2. Thanks. Keep it up!
+Munky332 Some of the chinese isn't even close in quality. We have a bunch of dial calipers in my machine shop class at a school, and if you open and close them they usually never close within 5 thou of the previous close. Complete trash.
I mean 5, sometimes 10 entire thousandths. They have not been taken care of, and they are the cheapest of the cheap. Some of the better Chinese ones there are ok.
FWIW, I was taught to use cotton glove liners when I handled gage blocks...the acid from your fingers would distort the blocks' dimensions...
Nice tip, but you should check the gage stack again after measuring your part to check that it repeats and the indicator stand hasn't shifted on you between setting it on the gage and testing the part.
Your wringing technique is interesting. Great video, thanks again for sharing.
I think an even better way to compare the height of two surfaces would be using an optical flat and monochromatic light. You will see light interference fringes and looking at the pattern and counting the fringes will allow you to measure differences in height of about 100nm (0.000004 inch)
Yes! An RPN guy... gets a thumbs up for that alone! Couldn't tell if it was an 11,12 or 15C.
Great videos, thanks!
+NYC CNC Suspect you've seen this... but on the outside chance:
www.hpmuseum.org/
Tons of good old HP stuff there; years ago picked up a 15C emulator from their site... have used it multiple times a day ever since.
That 12C popped right into my eyeball. My initial thought was that you could calculate your mortgage payments right there in shop. I have owned a bunch of them over the years going back to the original model with flashing red led's. Thanks for the vids.
great video. after Abom79 showed a book, "Dimensional Metrology" , found a copy of the 3rd ed on ebay. is a great read, to top off more practical work shop techniques we get to see you and the other guy show.
Keep up all the great work.
I am making balls and you have a set of balls!!...wringing the 3"&4" gage blocks then showing how the hold while holding them over your gage block set.....if I did that I would have had a great bloopers crash....lol
Enjoyed!
At my shop we use a dial indicator attached to a height gage (similar to the one you have on the datum table there). With this setup it is very easy to measure hole locations by running the dial indicator over the gage pin in the hole and subtracting the radius to get the center line of the hole. I spend a lot of time with dial indicators at work.
+NYC CNC. We also have indicators attached to an adjustable arm (similar to yours in the video) with a magnetic base. We attach the base upsidedown on an empty spindle and are then able to use this to square up vices, check flatness on parts while they're in the vice, and other general measurements inside the machine. we can use the handle jog to move the table around and use the indicator that way.
FYI the indicator tip stem should be, depending on the model, 12° of parallel not parallel. They are designed this way so that the body of the indicator to clear the workpiece.
Edit - My bad, this doesn't apply to all dials though so you need to check if it is a 'corrected' or not and what angle it is corrected for, that brown and sharp you have I believe is 12° stem angle.
Any real reason to measure with indicator about a mile from the height indicator base ? I would slide that rod way back in and let it hang out the rear of the height indicator. You have a giant lever an might tend to jack the front of the indicator base up off the granite table a tenth or two.
Important Tip on gauge blocks and pin gauges!....store and use them in a room temp area "68-72f or Celsius equivalent"..Even if you only use them to check and set your calipers/mic's its important your gauges and parts are at the same temp for qc checks....very easy to bounce off your high/low tolerance limits if your doing precision work.
Thanks for the video.
As I only have 0--1 and 1-2 micrometers, this extends my measuring capabilities. I don't have a set of gage blocks, so I have used 1-2-3 (and 2-4-6) blocks with adjustable parallels (measured with the micrometer) for the fractional part of the measurement. Not as good as gage blocks, but a lot better than dial/digital/vernier sliding calipers (all of which I do have). Slide calipers (of whatever style) seem to vary by a thousandth or more each time you measure an object unless ther object is extremely smooth and regular.
I measured the block dimensions in as many locations as I could reach with the small micrometers, and then checked for flatness/parallelism on the surface plate (cast iron) with a surface gauge and tenths-reading indicator. Then I started stacking the smaller blocks and using those known heights to check the larger dimensions of the blocks by comparison using the indicator. My blocks are surprisingly good considering that they are run-of-the-mill blocks. None are out by size or parallelism by more than a few tenths, and knowing the error, I can make stacks where the errors offset each other.
Great video. Thanks.
Excellent tutorial
thank for the gage block set up site at Little Machine Shop
Great video !
Thanks, good info!
That was great. Thank you.
Another item added to the wish list :)
thanks for the tip. bob
Nice one buddy...
You're videos look better in your new shop. I'm not sure why, maybe it's the white walls. (Not that your videos looked bad before.) Are you liking the new shop?
I don't agree with the primes of the video. Is the surface plate and gauge blocs a cheaper more accurate alternative to handheld measuring tools? A set of tools at the side of the surface plate gets vary expensive quickly. For direct linear measurements nothing beats the conveyance of hand held tool, the plate and accessories are intended to be used for measurements of surfaces that are obstructed, note easily referenced or not directly opposed.
Aherm, sorry John - just watched this again and you talk about the little test indicators from China ;-) I had missed that part before!
Great tip John, thanks for sharing!
Ray
I don't see how this is better than a micrometer. A good mic will measure 0.0001 inch accurately. Yes, a gage block is far more accurate than that, but the error introduced by your dial indicator is greater. Also, you're supposed to use wear blocks on the ends of your stack of gage blocks to prevent slow wear of your blocks (you periodically replace the wear blocks).
Unless im missing somthing here & unless I was working to really close tolerances my choice would be a digital height vernier with a DTI Indicator.
zero on the work piece then zero on to the surface table or vice versa read off the size quick & accurate.without a huge expense I did like the software chart application for working out the minimum amount of slips stack though . :-)
What's the difference between parallels set and gage blocks?
Kayode Odeyemi precision
WHY do you have that indicator hanging on the end of a 14 inch boom??? The slightest change on the surface gage will be magnified 20 times at the indicator.
Can you measure the difference between gauge blocks that have and have not been rung together?
Yes, but you need an interferometer. The film between two blocks is about one millionth of an inch thick.
High-precision blocks are manufactured to correct for film thickness. Each block is thinner by one film, so if you wring three blocks between two parallels you'll have 4 films with 3 films corrected for. If you use 12 blocks, that's 13 films with two corrected for.
So, no more than 1-2 millionths of an inch uncertainty comes from the film effects. This is most likely negligible compared to whatever method you're using to compare lengths.
If you're measuring at such precision that the film thickness is a deal-breaker, you probably need interferometry anyway.
Very cool! But hey! I have the same exact calculator! I just pulled it out of a drawer today and looked at it and though "hmm I'll hang on to this" :) How cool is that? :)
+NYC CNC Ok, so your's a 12C, mine is an 11C. It was a dumpster find a few months back! I wacked some batteries in and tried it just now. RPN is cool but I had too google it! ;)
+Torsan1977 There is a little learning curve to RPN... but once you get the hang of it, you'll never look back. Well worth the effort, quick clean intuitive; more like you'd think if you were going to do the problem on paper.
When using a large number of gauge blocks you'll want to reference the deviation chart that comes with the set. My NIST grade 3 set from Shars came with one. Whether it's accurate is another question... See this excellent video from suburban tool on the topic. czcams.com/video/ZS2uym83jCU/video.html
+JoshuaP I never knew deviation charts existed. Great video, thanks.
Gage blocks no where close to cheap
Gotta get me some
Gotta get me some
Gotta get me some
Ras great channel profile photo.
I have that anthropomorphic milling machine on the side of my toolbox.
Does anyone think they can work to one ten thousandths...
... it is not parallel to the surface, it is perpendicular to the indicator tail's movement !
Regarding choosing blocks, I learned that you start from the least significant digit and and work up from there.
This is what Stan @ BarZ #Shadon HKW teaches
Is that an HP 11C calculator?
+scubaseppy 12C for the win! I had one I bought used for $20. Kept it in my shirt pocket as an engineer and dropped it on the floor every time I bent over for a few years. Then I relegated it to my toolbox for a couple of hard use years. I finally sold it for $180 on eBay when they became collectable. Kinda wish I'd kept it. I managed to find a 33s which does have Reverse Polish Notation for something like $40 new, but it's like a Romulan tricorder with those weird angled buttons... assuming Romulan tricorders are cheaply made in China and have a decimal point and comma that are nearly indistinguishable. It looks like HP could make a good durable RPN scientific calculator like the 12C for $100 or less. Seriously. Why can't we buy these new? Why does every calculator need to be cheap crap?
+Liberty4Ever I have a 11C and 12C. The 11C pretty much lives on my desk. I put a 11C app (Andro11C) on my phone as well as the Machinist Calc Pro app from Calculated Ind. You can still buy the 12C new, but sadly, the 11C not been made in a long time. HP did a special 15C anniversary edition or some such about 5 years ago, but did not keep it in the lineup. Crazy prices for the old HP calculators on eBay.
+NYC CNC I still see 12C's for sale at Office Depot for around $70. It's the 11C and 15C that most of us gear heads desire and are rare/collectible/out-of-production. There are many more of the old HP's calcs that have equal or even greater appeal to some with fond memories and preference to RPN.
+gwcude I have the 11c app on my iPhone and I love it! A older engineer at my shop turned me on to the backwards HP entering system I laughed at first but once I got used to it I started to not be able to use a normal calc.
More good stuff, more good stuff, then... Yeah, more good stuff. Amazed how people share information rather than keeping it to themselves. Frikin brilliant.
Do you have a finance background?. (Because of the 12C)
I'm just a trainee, but aren't you supposed to use gloves when handling steel gauge blocks? Also, if the warmth of your hand causes that part to heat up by 18 F, that means ,3 thou. So this shows like the error of the instrument, meanwhile, you heated up the part, you were measuring.
The edge of the plate is not used for measurements! In this place it is not flat.
Awesome :-)
A Caddilac height micrometer is way faster
'Cheap way' eh? Who has a granite surface plate and a set of gauge blocks!! Not me!
He scratch my part :))
5:19 use metric and you won't need the sht )))
THAT is idiotic. Metric blocks are assembled EXACTLY the same way.
Easy and cheap is right. Like a $30 edge finder and a post-it note can replace your $400 Haimer and... it doesn't take any longer.
too bad you didnt have a 4 foot plate then you could have used a 2 foot arm on your surface gage with a weight to hold it down
funny the inch guys need this to learn the obvious !!!
how do you afford all this, supplemented off youtube? your inexperience is evident in watching most your videos. Is your job shop profitable without any supplement income from this pr stuff
Your running to much on your clock, you want to have a 0.01" load to the size you want to measure.
More good stuff, more good stuff, then... Yeah, more good stuff. Amazed how people share information rather than keeping it to themselves. Frikin brilliant.