Not A DRO

[jd99]

Thought you guys with the DRO on your lathes, would get a kick out of this.

This is one of 4 indicators I use when I work on Close tollerance Mold parts.

Yes your reading that dial right.. Thats 5 decimal places This is a 50 Millionths of an inch (.00005") indicator, each number is .001" so this only reads .008" total .004" on each side of zero.

These kind of tollerences are measured in controlled inspection room, and I have to have them callibrated every year.

Nope I don't use it on my Pens.... :wink:

 

[Rich L]

The Heidenhain DRO on my mill indicates to 78.7 millionths (.002mm)(2µm) but the Accurite lathe DRO is so sloppy it only goes to 394 millionths. What a piece of crap

I mean that is just too many millionths! :biggrin:

Cheers,
Rich

 

[maxwell_smart007]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

 

[Timebandit]

Yep thats 500thousandths. My DRO can be set to this, but i only use 10thousandths of an inch rather than 100thousandths

 

[PenMan1]

1/500,000th of a millimeter is a little closer than I measure...... By an inch or two.

Danny, who makes this DI?

 

[jd99]

1/500,000th of a millimeter is a little closer than I measure...... By an inch or two.

Danny, who makes this DI?

It's a Brown and Sharp, I have a couple of them the other's I have are SPI and Mitutyo, I've had them for years. I'm not sure Brown and Sharp make test indicators any more.

It would be nice to have digital stuff, but since I don't plan on keeping this shop that long, the old way will work just fine (it did for 20 years) :wink:

They still work fine, I just had to get the calibration certs updated: part of the contract with this customer, is that I supply copies of calibration certs that show the inspection and measurement equipment we use is reading correctly.

 

[jd99]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the h--- out of me???

 

[Timebandit]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the heak out of me???

And technically, it still is hundred-thousandths place. The TRADE cant change this, is a given. Work any math equation and this is the hundred-thousandths place. Could be a misprint is your manual. If not, its just really stupid. Why confuse people as to what measurement they are reading. It has been this way for hundreds if not thousands of years before measurement devices like this were invented. Il stick with the tried and true measurement rather than confusing myself and others. So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place. How can this be anywhere near accurate? Im sure you can get it to where you want it in your head, but gees, confusing when you are trying to take off 10thousandths and you really take off 1thousandths because you called the decimal places wrong. oops........

 

[jd99]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the heak out of me???

And technically, it still is hundred-thousandths place. Work any math equation and this is the hundred-thousandths place. Could be a misprint is your manual. If not, its just really stupid. Why confuse people as to what measurement they are reading. It has been this way for hundreds if not thousands of years before measurement devices like this were invented. Il stick with the tried and true measurement rather than confusing myself and others. So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place. How can this be anywhere near accurate? Im sure you can get it to where you want it in your head, but gees, confusing when you are trying to take off 10thousandths and you really take off 1thousandths because you called the decimal places wrong. oops........

It's not the manual, it's the certs that actually say that, you want to agure a point agure it with those that set this pseudo language up long ago, I'm not the one to start it with.

Just the way it is and has been since 1967 when I started in the trade.

 

[Timebandit]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the heak out of me???

And technically, it still is hundred-thousandths place. Work any math equation and this is the hundred-thousandths place. Could be a misprint is your manual. If not, its just really stupid. Why confuse people as to what measurement they are reading. It has been this way for hundreds if not thousands of years before measurement devices like this were invented. Il stick with the tried and true measurement rather than confusing myself and others. So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place. How can this be anywhere near accurate? Im sure you can get it to where you want it in your head, but gees, confusing when you are trying to take off 10thousandths and you really take off 1thousandths because you called the decimal places wrong. oops........

It's not the manual, it's the certs that actually say that, you want to agure a point agure it with those that set this pseudo language up long ago, I'm not the one to start it with.

Just the way it is and has been since 1967 when I started in the trade.

No arguing, just saying

Still didnt answer my question....So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place....how do you use this contraption using the wrong measurements?????

 

[jd99]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the heak out of me???

And technically, it still is hundred-thousandths place. Work any math equation and this is the hundred-thousandths place. Could be a misprint is your manual. If not, its just really stupid. Why confuse people as to what measurement they are reading. It has been this way for hundreds if not thousands of years before measurement devices like this were invented. Il stick with the tried and true measurement rather than confusing myself and others. So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place. How can this be anywhere near accurate? Im sure you can get it to where you want it in your head, but gees, confusing when you are trying to take off 10thousandths and you really take off 1thousandths because you called the decimal places wrong. oops........

It's not the manual, it's the certs that actually say that, you want to agure a point agure it with those that set this pseudo language up long ago, I'm not the one to start it with.

Just the way it is and has been since 1967 when I started in the trade.

No arguing, just saying

Ok Like I said I didn't get it long time ago, could be the way they write the dim. in words eg. 30 millionths, using the extra zero after the 3, takes it out another decimal place. Don't hold me to this just throwing stuff out there.

Most products don't use these kind of dim anyhow, usally the closest dim we work to is plus or minus .005"

These mold parts are made to be interchangable, in other words if they have spares they want to be able to pop a mold cavity out of the center of say a 12 cavity mold pull a spare off the shelf, and have it fit perfectly with out any modification. All parts are made exactly the same and exactly on center both width and height, and length. Thats why they want the close tollerances

Note, I work to the Decimal place not the wording, if I need to make a part to .00005 then thats what i work to I use measuring equipment that shows me .00005, I could care less if it's called a super widgit or whatever.

 

[Timebandit]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Technically yes I remember thinking that years ago, but in the trade it's called millionths??? don't know why been that way ever since I started.

I have a squareness checker and it is callibrated to .00003" and the doc says 30 Millionths of an inch.

Beats the heak out of me???

And technically, it still is hundred-thousandths place. Work any math equation and this is the hundred-thousandths place. Could be a misprint is your manual. If not, its just really stupid. Why confuse people as to what measurement they are reading. It has been this way for hundreds if not thousands of years before measurement devices like this were invented. Il stick with the tried and true measurement rather than confusing myself and others. So what do you call the tenths place, hundreths? Because it cant be tenths if thats the millionths place. How can this be anywhere near accurate? Im sure you can get it to where you want it in your head, but gees, confusing when you are trying to take off 10thousandths and you really take off 1thousandths because you called the decimal places wrong. oops........

It's not the manual, it's the certs that actually say that, you want to agure a point agure it with those that set this pseudo language up long ago, I'm not the one to start it with.

Just the way it is and has been since 1967 when I started in the trade.

No arguing, just saying

Ok Like I said I didn't get it long time ago, could be the way they write the dim. in words eg. 30 millionths, using the extra zero after the 3, takes it out another decimal place. Don't hold me to this just throwing stuff out there.

Most products don't use these kind of dim anyhow, usally the closest dim we work to is plus or minus .005"

These mold parts are made to be interchangable, in other words if they have spares they want to be able to pop a mold cavity out of the center of say a 12 cavity mold pull a spare off the shelf, and have it fit perfectly with out any modification. All parts are made exactly the same and exactly on center both width and height, and length. Thats why they want the close tollerances

My point is that those tolerances are still there with hundred-thousandths...calling it millionths doesnt make it more accurate. Just changes the name. How is this more accurate?

 

[Justturnin]

....I need that on my wood lathe.....

Found a thread on this exact subject and pretty much, from what I read knowing nothing, is that is how machinist roll. It appears that the 1.0" on these types of micros is actually the Tenth space in a shop measuring tolerances like these so 0.1" is actually a hundredth of an inch. No one was able to say why but they do say that's just the way it is and it is accepted and understood in their circles.

Danny,
Is this the gauge you are using on the tolerances for the injection mold parts you were showing?

 

[jd99]

....I need that on my wood lathe.....

Found a thread on this exact subject and pretty much, from what I read knowing nothing, is that is how machinist roll. It appears that the 1.0" on these types of micros is actually the Tenth space in a shop measuring tolerances like these so 0.1" is actually a hundredth of an inch. No one was able to say why but they do say that's just the way it is and it is accepted and understood in their circles.

Danny,
Is this the gauge you are using on the tolerances for the injection mold parts you were showing?

Yep, it's one of the test indicators I use to check my parts when I'm grinding them to finish dim.

I use a set of high precision gage blocks set to my dim then use the test indicator to check how close I am and how much I have to grind off (hopefully it's take off :wink. all this inspection is done on a pink rock (mold maker lingo for a high precision surface plate)

 

[Justturnin]

Yep, it's one of the test indicators I use to check my parts when I'm grinding them to finish dim.

I use a set of high precision gage blocks set to my dim then use the test indicator to check how close I am and how much I have to grind off (hopefully it's take off :wink. all this inspection is done on a pink rock (mold maker lingo for a high precision surface plate)

Wow, what are the specs on the pink rock that is used to spec? Then, what are the specs for the machine that specs them.....:befuddled::hypnotized::question::bulgy-eyes:

 

[jd99]

Yep, it's one of the test indicators I use to check my parts when I'm grinding them to finish dim.

I use a set of high precision gage blocks set to my dim then use the test indicator to check how close I am and how much I have to grind off (hopefully it's take off :wink. all this inspection is done on a pink rock (mold maker lingo for a high precision surface plate)

Wow, what are the specs on the pink rock that is used to spec? Then, what are the specs for the machine that specs them.....:befuddled::hypnotized::question::bulgy-eyes:

I know the B grade they can come in inspect them in the shop and resurface them there; these are black granite and close enough for 99% of what we do, we have a 36" x 48" one in the shop.
The AA grade we have to send out, and they are usally made of pink granite (never seen an AA that was not pink). I have two of these that are mine (Not the Shops) 18" x 24" and 24" x 24" two ledge.
I'm attaching a PDF I just found.

 

[Justturnin]

I know the B grade they can come in inspect them in the shop and resurface them there; these are black granite and close enough for 99% of what we do, we have a 36" x 48" one in the shop.
The AA grade we have to send out, and they are usally made of pink granite (never seen an AA that was not pink). I have two of these that are mine (Not the Shops) 18" x 24" and 24" x 24" two ledge.
I'm attaching a PDF I just found.

Ummm....yea...I have no idea what any of that means. hahahahah.

 

[jd99]

I know the B grade they can come in inspect them in the shop and resurface them there; these are black granite and close enough for 99% of what we do, we have a 36" x 48" one in the shop.
The AA grade we have to send out, and they are usally made of pink granite (never seen an AA that was not pink). I have two of these that are mine (Not the Shops) 18" x 24" and 24" x 24" two ledge.
I'm attaching a PDF I just found.

Ummm....yea...I have no idea what any of that means. hahahahah.

Here ya go Pictures:
A surface plate, and building a race car on a big surface plate.

 

[maxwell_smart007]

I feel like we're arguing Plato's allegory of the cave!

I guess what the industry is doing is using TENTHS as base, rather than one...then the hundred-thousandth position is a hundred-thousandth of a TENTH of an inch, rather than of an inch..which would make it a millionth...

Likely it resulted from people in the industry measuring tenths of an inch all the time - and then someone came up with a more accurate measurer that could measure a tenth of that...It's still a bit inane to change a measuring paradigm, however..

 

[Timebandit]

I guess i was wrong about my DRO....i guess it will measure in millionths........

 

[Justturnin]

I guess i was wrong about my DRO....i guess it will measure in millionths........

I would say they all do. The question is will it move the Dial enough for you to notice. I think the deal is the specs you are trying to reach. I am seeing dials starting at 1/1000". If your dial is a total of 1" all the way around I doubt you would be able to a millionth but if full circle around the dial is a mere 0.1" then you would likely be able to tell the difference between 0.00001 and 0.000001

 

[Timebandit]

I guess i was wrong about my DRO....i guess it will measure in millionths........

I would say they all do. The question is will it move the Dial enough for you to notice. I think the deal is the specs you are trying to reach. I am seeing dials starting at 1/1000". If your dial is a total of 1" all the way around I doubt you would be able to a millionth but if full circle around the dial is a mere 0.1" then you would likely be able to tell the difference between 0.00001 and 0.000001

But it will be a millionth. It will actually be a hunderd-thousandths, which my DRO will pick up, but i will call it millionths, so that i am in specs now. Same as the dial indicator above. Its in hundred-thousandths, as all are, just called millionths. Same measurement.

 

[Justturnin]

But it will be a millionth. It will actually be a hunderd-thousandths, which my DRO will pick up, but i will call it millionths, so that i am in specs now. Same as the dial indicator above. Its in hundred-thousandths, as all are, just called millionths. Same measurement.

I can't argue these points with you but this seems to be a standard accepted by the industry so what is the point. I would not say they are dumb or wrong because I do not understand. I am sure there have been calculations beyond what I can fathom to get to this scale that seems to have been accepted in the engineering community for quite a while.

edit:

 

[Timebandit]

But it will be a millionth. It will actually be a hunderd-thousandths, which my DRO will pick up, but i will call it millionths, so that i am in specs now. Same as the dial indicator above. Its in hundred-thousandths, as all are, just called millionths. Same measurement.

I can't argue these points with you but this seems to be a standard accepted by the industry so what is the point. I would not say they are dumb or wrong because I do not understand. I am sure there have been calculations beyond what I can fathom to get to this scale that seems to have been accepted in the engineering community for quite a while.

edit:

No need to argue. I was just joking that my DRO will measure Millionths.:biggrin: Which it will if i call it that to meet industry specs, and it will measure it, 5 decimal places, .00005. I realize they did this for some reason, not sure what, but it doesnt change the laws of mathematics or these measurements. These specs just make the the user call thousandths millionths to conform to their wording, thats all. Im just happy that my DRO can meet these industry standards.:biggrin:

 

[Rich L]

Just some more examples of how the "lingo" is used even with some popular machinery. In addition to South Bend, any number of precision tool-room lathes spec their spindle runouts to "50 millionths." Measuring equipment in that realm keeps to the lingo as well and they can actually measure down to and below single-digit millionths.

South Bend Lathe Co.
Machining: find A cnc machine shop with CNC turning and milling, CMM, CAD, CAM, METRIC.

and many more

With respect to actually turning out a part with a 50 millionth runout spindle, you will not necessarily be able to create a part with that runout because of additional collet, tool deflection, temperature, etc. inaccuracies that build on that initial error.

Also, it's conventional lingo in the upper realms of measurement (still less than an inch) to say something like ".310" as "three hundred and ten thousandths" instead of thirty-one hundredths even though they're both correct.

Cheers,
Rich

 

[jd99]

Just to add a point, anytime you go to these kind of dimensions .0000x", or even .000x" unless your equipment is in a industry standard controlled environment then saying you can hold them because your DRO has that display really isnt true.

Temperture change can move a part quite a bit depending on what type of material it is.

The grinders I work with are in a controlled environment, and even the slightest bit of temperture change (like grinding) can move the part out of tollerances, it's not as easy as reading the number on a DRO, (which the grinders I use do have), this is why we constantly have to check the parts (take them off the grinders, let then stabilize and put them on the surface table), not only do we have to hold the dimension, we also have to hold the centerlines, squareness, flatness, and position to the cavity.

Not really that easy.

Just Saying :biggrin:

I find it odd, that me just showing a test indicator that is not digital readout (Which I thought some would get a kick out of), has become an agurement in symantics as such.

Really nothing to agure about.

 

[Timebandit]

Was joking about the DRO...................Wasnt arguing, Was just confused by it all, as were the first few posters in this thread, sorry i joined in...........

 

[Rich L]

Just to add a point, anytime you go to these kind of dimensions .0000x", or even .000x" unless your equipment is in a industry standard controlled environment then saying you can hold them because your DRO has that display really isnt true. Right on!

Temperture change can move a part quite a bit depending on what type of material it is.

The grinders I work with are in a controlled environment, and even the slightest bit of temperture change (like grinding) can move the part out of tollerances, it's not as easy as reading the number on a DRO, (which the grinders I use do have), this is why we constantly have to check the parts (take them off the grinders, let then stabilize and put them on the surface table), not only do we have to hold the dimension, we also have to hold the centerlines, squareness, flatness, and position to the cavity.
...

I find it odd, that me just showing a test indicator that is not digital readout (Which I thought some would get a kick out of), has become an agurement in symantics as such. Thanks for posting the picture. I compare it to a couple of mine that only go to "hundreds of millionths."

...

With respect to the grinding comment - I've experienced temperature problems quite often because of the localized heating. This is especially true when grinding dry but still can manifest itself with flood coolant. The handwheel on the surface grinder is graduated in tenths (of thousandths) but sometimes even a second or third pass to "spark out" the surface at the same depth will run into what I'll call "temperature bumps" from earlier passes.

What's all that got to do with pens? I use this kind of equipment to make tooling to hold pen parts and to make tooling to make tooling. It never ends. I also use the surface grinder to mate Damascus slab surfaces for reforging.

Cheers,
Rich

 

[Rich L]

Was joking about the DRO...................Wasnt arguing, Was just confused by it all, sorry i joined in...........

If folks didn't join in, confused or not, it wouldn't be much of a forum. It's hard to read writing with the same flavor as hearing it spoken.

Cheers,
Rich

 

[jd99]

What's all that got to do with pens? I use this kind of equipment to make tooling to hold pen parts and to make tooling to make tooling. It never ends. I also use the surface grinder to mate Damascus slab surfaces for reforging.

Cheers,
Rich

Doesn't have anything to do with pens, just trying to point out just because a DRO has 5, 6, or 7 decimal places doesn't mean that you can hold those kind of dimensions. and that it take a controlled environment to work to close tollerances.

Just Informational stuff :biggrin:

FYI we use a Mitsui Surface grinder with the optional "Fine .00001" (0.001 mm) feed atachment"

Have a good day.

 

[Timebandit]

What's all that got to do with pens? I use this kind of equipment to make tooling to hold pen parts and to make tooling to make tooling. It never ends. I also use the surface grinder to mate Damascus slab surfaces for reforging.

Cheers,
Rich

Doesn't have anything to do with pens, just trying to point out just because a DRO has 5, 6, or 7 decimal places doesn't mean that you can hold those kind of dimensions. and that it take a controlled environment to work to close tollerances.

Just Informational stuff :biggrin:

Have a good day.

This is the third time i have said this in this thread....it was a joke about the DRO....so relax...we know what you meant.......im the only one who said it, not Rich or anyone else, and again i was JOKING! You work in these enviroments, i dont and most here dont, which is why most were confused.....I stand corected. Thank you for informing me and all who were confused and thought this dial indicator made finer measurements than the dial indicators they own. It doesnt, its an industry thing. Again, Thank you for the information, i stand corrected and humble. You are very intelligent, and have many years of experience in this field. Again i thank you:wink:

 

[raar25]

FYI just some sombering news for everyone, that degree of percision adds nothing to the system unless it is in a controlled atmosphere and mounted on a vibration isolating granite system. So whether its .00005" or .0000005" on your DRO anthing measuring finer than .0001" is just not usefull since the GRR (gage repeatibility/reproducibility ) is probably > 1000% on 5 decimal places and the material thermal variation outside a lab could easily equal .00005"/inch.

By the way I though most of the lathes that said DRO meant digital read out!

 

[hanau]

I transferred into an new job last year where i had to start dealing with small measurements. I am having to relearn how to say these small measurements.

I have to have them to write them down for me when I have to grind stuff.

the way we where taught in school

 

[Rich L]

... (something about intelligence) ... Again i thank you:wink:

Justin,

Not as much as you think :biggrin: Thanks for entering the discussion. I'm chilled :wink:

Continuing ...

If the measurement gage, pin, DRO, dial is made properly then it can measure or indicate more "precision" than another with lesser quality or fewer graduations. These dial indicators (Danny's) will measure relative precision to some calibrated error around the tick mark on the dial face (that's why Danny has them calibrated once a year). But, you're right in one respect in that you can't just add tick marks and expect additional measurement precision. The capability has to be inherent in the manufactured quality of the indicator.

By the way, if you didn't know, measurements of this tiny a value are in the realm of the wavelength of near-infrared light. Any more precision gets into optical measurement technology never mind the environment required. Purely academic for what's made here.

Still chilled!

Cheers,
Rich

 

[azamiryou]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Sorry to bring up old stuff, but "it's incorrect math but that's the way they do it" is an unsatisfactory response - mainly because it is NOT incorrect math. .00005 can be expressed as either 5 one-hundred-thousandths, or 50 millionths. Mathematically, they are the same: 5 x .00001 or 50 x .000001, but "millionth" is way easier to say and less prone to ambiguity than "hundred thousandth". For example, is "five hundred thousandths" .500 or .00005?

To do this with millionths is no stranger than, say, measuring the lower barrel on a Gentlemen's pen to be .600" and referring to it as 600 thousandths rather than 6 tenths. Or saying something is 2200 mm instead of 22 decimeters.

 

[maxwell_smart007]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Sorry to bring up old stuff, but "it's incorrect math but that's the way they do it" is an unsatisfactory response - mainly because it is NOT incorrect math. .00005 can be expressed as either 5 one-hundred-thousandths, or 50 millionths. Mathematically, they are the same: 5 x .00001 or 50 x .000001, but "millionth" is way easier to say and less prone to ambiguity than "hundred thousandth". For example, is "five hundred thousandths" .500 or .00005?

To do this with millionths is no stranger than, say, measuring the lower barrel on a Gentlemen's pen to be .600" and referring to it as 600 thousandths rather than 6 tenths. Or saying something is 2200 mm instead of 22 decimeters.

I'd never say 600 thousands, personally...6 tenths is easier to understand...I see what you're saying...50 millionths is 5 hundred thousandths, or 500 ten millionths, but I just don't think it's easier...

I still think it's easier to not add a zero and move down the number line when on the right side of the decimal...or on the other side, for that matter...

I.e. we say 5 hundred, not five tenths of a thousand!
(When it comes to math, I like simplicity)...

 

[dbledsoe]

I'm confused - wouldn't 5 decimal places be 5 hundred thousandth, rather than 50 millionth?

Sorry to bring up old stuff, but "it's incorrect math but that's the way they do it" is an unsatisfactory response - mainly because it is NOT incorrect math. .00005 can be expressed as either 5 one-hundred-thousandths, or 50 millionths. Mathematically, they are the same: 5 x .00001 or 50 x .000001, but "millionth" is way easier to say and less prone to ambiguity than "hundred thousandth". For example, is "five hundred thousandths" .500 or .00005?

To do this with millionths is no stranger than, say, measuring the lower barrel on a Gentlemen's pen to be .600" and referring to it as 600 thousandths rather than 6 tenths. Or saying something is 2200 mm instead of 22 decimeters.

I read this whole thread thinking "What's the deal? They are the same number." You said it better than I could.