Square vs Square

[@das250250]

A couple of notes: How do we know what temperature/humidity these squares were made at and would the error found in the granite be enough to produce the error? I researched that coefficient of expansion was 7.9 -8.4 x10-6 inches / inch / Fahrenheit so over 10" this could be 84x10^-6 inches x a temperature differential of 10degrees far = 840 x10^-6 = 0.8 x10^-3 = 0.8 thou. A 5 degree difference would yield 0.4 thou = 4/10ths of movement.

[@TheAndyJBall]

i love the coffee cup rings on the calibrated surface

[@shannonsears3496]

I don't see the use of granite squares and angle plates. Cylinder squares and steel angle plates do the same thing and more. What do people use them for, transferring high spot blue for scraping? There is a B&S granite angle plate at work that just collects dust. Nice video, TY.

[@lookcreations]

Nicely done Stan - just wondered why you didn't sit the test subject on its other face to see if the out of square was in the opposite direction - or if the variation was just part of the face checked - it seamed to drift after first 25% of the length was climbed. Checking both faces would be self proving in effect. Thanks for these vids - they help a lot. All the best Mat

[@ShadonHKW]

Hey Mat, I actually mapped the sweep and your right, it slowly tapers the first 75%, then drops off hard the last 25%

[@lookcreations]

you are 'the man' Stan. All the best Mat

[@waynegotthardt3233]

Just wondering if the Square Master was calibrated @ right angles to the face of the Granite Square as it would show an error checking the Cylinder Square if the travel doesn't follow the Center Line of the Cylinder

[@ShadonHKW]

Wayne Gotthardt Yes, it gets calibrated on both axis, but the camera hits, so I cant film it.

[@Nobody-ld7mk]

I'd have liked to have seen you lay that chinesium granite horizontal and proved it's sway backed with a surface gauge.

[@ScottGMerritt]

Thanks again, Stan. Excellent video.

[@SolidRockMachineShopInc]

Nice video Stan. How do you like the white face Brown & Sharpe indicator? I love mine. Steve

[@ShadonHKW]

Hey Steve, yes, easy to read and repeats really nice. Just not very camera friendly, I got lucky on this one.

[@SolidRockMachineShopInc]

Same problem here, that is one of the main reasons we bought the Amp. With the Amp viewers can see the indicator movement better. Steve

[@harlech2]

The shipping alone back and forth cost him more than buying a decent square from a good manufacturer.

[@SteveSummers]

Nice video Stan, No way they would just print up a bunch of certs and throw them in the box without checking them;-)

[@lwilton]

If it doesn't have a serial number and initials it isn't a cert, it is just a page off a pre-printed notepad.

[@duobob]

I call that "pencil whipped." Though today maybe it is "laser jet whipped." A good test like Stan gave it tells the tale...

[@SteveSummers]

Yeah, Stan did a very good job of cal / test / cal / test and compare. from the looks of things the cert sheet was just a copy thrown in every box.

[@felixf5211]

I have that same Asian granite square. It's spec'd at +/-.0001. The same paperwork came with mine, too. Mine meets spec or a little better. Hard to complain for the money. I paid about $100 NIB.

[@bearsrodshop7067]

Darn it, this was crazy fun to watch, if I send you my bride could you recalibrate her?? think after 42 yrs she is out of plumb,,,😜

[@ajtrvll]

Can anyone provide a good explanation as to how and why those horrible screeching sounds occur when sliding 2 flat surface together?

[@ShadonHKW]

Try this en.wikipedia.org/wiki/Stiction

[@ajtrvll]

Thanks... I am familiar with static friction but I did not know the term 'stiction'... but how is that screeching sound generated? Is it the square that's bouncing up and hitting the surface plate extremely rapidly: sticks - crosses the threshold - skips (slides in the air) - lands (noise) - sticks again - and so forth?

[@lwilton]

I'm not sure there is necessarily a vertical component involved. The square is motionless, force is applied parallel to the plate. The friction is overcome and the square suddenly moves horizontally a small amount. This reduces the force applied because the square moved faster than the applied force. The hand moves farther, force is applied again, builds up, the square moves a small amount. Repeat. When the square moves it pushes on the air. It is a 10" speaker cone. It couples the small sudden movements to the air. They occur frequently, thus a high pitch.

[@ajtrvll]

I wilton: Thanks...that's a good explanation... I particularly like the 'speaker cone' effect. I believe you are describing phonons. So the pitch of the screech would be function of the size and shape of the square? How does the size of the square-plate contact area and the weight of the square affect the pitch?

[@lwilton]

The pitch and timbre of the screech would be a function of how far the square moves in each jump and how fast the jumps happen. That could be affected by the weight of the square and the size and maybe shape of the contact area, but is probably more a function of the relative surface roughness. A larger square is heavier, and is also larger, so a larger contact area with the air and probably a higher perceived loudness.

[@ROBRENZ]

Very nicely done Stan! 2.9 microns is more likely what they meant at 0.000114" which is close to what it read. 50 millionths is half a tenth. ATB, Robin

[@ShadonHKW]

Was hoping you would pop in and chime in on that one :)

[@afnDavid]

Ah Ha! SI (Systeme' International)

[@afnDavid]

I will have to nitpick a little bit about how machinists say things like "half a tenth" or 2 tenths... etc. When they really mean half a tenth of a thousandths .. Also It can be very confusing when I hear someone say something like 'lets dial in 4 thousandths ' on their lathe. Is that 0.004 diameter or radius? You really have to watch closely!

[@bcbloc02]

Looks out by about 0.00025 to me. I wonder if it was warmed up 50 degrees or cooled down 50 if it would come into spec?

[@lwilton]

"Dial in 4 thousandths" means just that -- adjust the dial by .004+-, or maybe set it to .004. Whether that is diameter or radius depends on who made the lathe, there is no standard.

[@sto2779]

What is that bluish greenish device called?

[@ShadonHKW]

That is called a squaremaster.

[@sto2779]

@@ShadonHKW Thanks for the reply. What is a low cost way to measure squareness for tall parts like how the squaremaster does? Is it ideal to use a tall machinists try square and a tall surface gauge with a test indicator? I'm assembling a small desktop CNC and would like to know the squareness of the column beams similar how the squaremaster measures. Also what is the instrument called for a "sqauremaster" are there any other brands besides the one you have?

[@ShadonHKW]

@@sto2779 PMC is the company that makes the squaremaster. auto-met.com/pmcgage/Default.htm

[@ShadonHKW]

@@sto2779 A granite plate and granite square could be used to check your CNC table.

[@sto2779]

@@ShadonHKW Granite square are super expensive, I'm assembling an Ender-3 3D printer, can I use 5 matched pairs of 1-2-3 blocks stacked, aligned and bolted to make a 20" square as an alternative to a granite square?

[@multiHappyHacker]

How do you balance your grinding wheels?

[@lwilton]

.001 - one thousandth .0001 - one tenth (of a thousandth) .000001 - one millionth Let's do that again: .001000 - one thousandth (1000 millionths) .000100 - one tenth (100 millionths) .000050 - half a tenth (50 millionths) .000001 - one millionth If you remember that a millionth is 6 digits (5 zeros and a 1) and extend all of your other numbers to 6 digits, it is easy to just read off how many millionths the number is.

[@duobob]

It is more communicative and less confusing...

[@ourclarioncall]

l wilton If .001000 is one thousandth .000100 is one tenth what is .000010 ?

[@scroungasworkshop4663]

I really enjoyed your video thanks. I thought it was a relevant test to get some idea on where the Chinesium accuracy may be at. I find it amusing reading all the armchair experts go on about how many thou it’s actually out by and then trying to compare that to the metric spec sheet. Two tenths of a thou, seriously what are you guys making in your home shop that two tenths of a thou is going to matter, a fucking laser beam to hit Pluto? And if you are that concerned about accuracy why would you even consider buying massed produced gauges from China when you can buy perfectly calibrated instruments that are made in America, all be it ten times the price. You get what you pay for.

[@836dmar]

When I get past 10ths my head spins so...

[@markmauzey1887]

Opinion on import surface plate quality? Wear rate?

[@ShadonHKW]

When it comes down to it, no human "makes" the granite, we just make it flat, mother nature gives us the raw material. So I dont think wear rate is really even an issue.

[@markmauzey1887]

I never thought of that! Thanks!

[@barrycass2820]

Hi Stan keep up the vice

[@VincentParisien]

Can it be improved?

[@ShadonHKW]

Of course, cast iron lapping plate and micron rated diamond abrasive.

[@ajtrvll]

I suppose it could be shimmed and ground flat with a diamond wheel (FYI, I'm no expert... just spit-balling ideas)

[@ajtrvll]

What I meant to say was: cast iron lapping plate with diamond abrasive... probably micron rated ;)

[@thomasallan5042]

Are you sure the calibration sheet wasn't in metric? 2.9 microns is ~ 74 millionths of an inch or 0.7 tenths which would be much more realistic

[@ShadonHKW]

It was expressed as "UM" so quite possibly metric, even if this is the case, they didnt make .7 tenths. Still thinking these data sheets are mass produced and crammed into the box with each shipment.

[@thomasallan5042]

That'll most likely be metric then, though it should be expressed as "µm" for microns. I wouldn't be surprised if the Chinese stuff isn't even inspected before it's shipped off.

[@ShadonHKW]

Thats the symbol I was looking for, couldn't find in my character library on this keyboard, thanks for the comment.

[@dimtt2]

Just add Greek to your language preferences on your computer settings,then switch your keyboard to greek and type "m" and out will "μ" come on your screen. Cheers from Athens

[@TgWags69]

Or just google mu, find a good example, then copy paste into your text

[@MrTooTechnical]

Fukin awesome

[@sharkrivermachine]

It will cost as much to ship it to Australia as he paid for it :-)

[@ShadonHKW]

I have a crate going that way anyway :)

[@Hirudin]

It's not a good day not to be square on KZbin. (Tom Lipton just put out a square-verification related video as well. :) )

[@ShadonHKW]

Saw that, what are the odds? Obviously pretty good.

[@ajtrvll]

Is it hip to be square, again?

[@afnDavid]

2.9 Millionths of an Inch (0.000,002,9 Inches) claimed vs 0.000,2 measured. Or roughly 100 X over-claimed accuracy. Actually I don't think it's possible for this Chinese manufacturer claim an accuracy to that level because of surface roughness (porosity of granite). Move that decimal 2 places to the right would be more like it , or 290 Millionths !

[@pauldiaz4273]

50 millionths or 5 hundred thousandths would be half a ten thousandths

[@ourclarioncall]

l wilton If .001000 is one thousandth .000100 is one tenth what is .000010 ?

[@ourclarioncall]

Can you call .000010 a hundredth of a thousandth of an inch ? Or is is a thousandth of a thousandth of an inch ? and could you can .0000001 A thousandth of a thousandth of an inch? Or is it a ten-thousandth of a thousandth of an inch I am from UK

[@Molb0rg]

Your's is huuuge :D

[@nilzlima3027]

bearn et