# Found some goddies



## lotsasteam (Feb 6, 2013)

i wish they would be metric!!![/ATTACH]


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## jmshep (Feb 9, 2013)

I mostly use DTIs for alignment rather than measurement so the scale doesn't really matter. Two nice examples - enjoy!


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## Art K (Feb 9, 2013)

I acquired one of these tachometers from my Dad, were can I get a replacement rubber end, the one you hold to the center of the shaft?

Art


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## f350ca (Feb 9, 2013)

I made a replacement for mine out a a short length of glue stick. Yes its sticky but can be drilled and pointed in the lathe. Works like a charm.
Greg


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## lotsasteam (Feb 9, 2013)

The truth guy's: I am on the war path with inches,i can read 1inch,1/2,1/4,1/8,1/16 and than its guesswork! If somebody has this goody's in   metric i'll trade or i have to sell these,sorry i have no clue how to use/read them!  E-mail me with offer,i guess i have to post them in the 4 sale Line.

Manfred


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## va4ngo (Feb 9, 2013)

jmshep said:


> I mostly use DTIs for alignment rather than measurement so the scale doesn't really matter. Two nice examples - enjoy!


 
I agree here. I have both Metric and imperial dti's and both are excellent for truing up a part in the 4 jaw.


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## kf2qd (Feb 10, 2013)

What's this metric, and what is it used for???


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## Woodster (Feb 10, 2013)

lotsasteam said:


> The truth guy's: I am on the war path with inches,i can read 1inch,1/2,1/4,1/8,1/16 and than its guesswork! If somebody has this goody's in   metric i'll trade or i have to sell these,sorry i have no clue how to use/read them!  E-mail me with offer,i guess i have to post them in the 4 sale Line.
> 
> Manfred



General rule of thumb is .040" (.0394") is equal to 1.0mm. So 4 divisions on the dial will be .1mm. Pretty simple to convert between English and metric, just divide or times by 25.4, depending on which way you are converting. Not worth selling to replace with metric as it will still work to true up or indicate a part regardless of it being English or Metric.


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## dman (Feb 10, 2013)

don't sell. they are great for checking runout and other things. if you want to use them on your lathe x and z for measuring then I see a problem unless you just use them to return to a reference point or you decide to work from imperial blueprints. 

.0005" is a tad more than .01mm (.0127mm) and .001" is about .025mm (.0254) so if you are checking flatness or runout just look at the divisions as .01 and .025mm respectively.

for a size reference a human hair can be between .003-.005" and a sheet of paper is about the same.


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## purpleknif (Jul 19, 2013)

If tou don't like fractions get a scale w/ .02 divisions. I \'ve been using them for years and don't even think fractions anymore.


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## /// (Jul 19, 2013)

kf2qd said:


> What's this metric, and what is it used for???


[required text to meet forum 10 char minimum]


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## Coyote_Physics (Jul 19, 2013)

Is there anyone here who knows how much they weigh using the SI units? As a physics teacher this is my standard question to anyone who feels like they know "all about the metric system," and don't want to review it.  It's important to remember that kg can not be used to measure weight, which is a force.


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## aarggh (Jul 19, 2013)

Ha ha, love it! I must admit I do a lot of support for systems and it's always confusing when dealing with files or references to dates that may have originated from the US timezone, I usually then find a reference one to work out if it's US, or the rest of the world's dating method.

cheers, Ian


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## aarggh (Jul 19, 2013)

Coyote_Physics said:


> Is there anyone here who knows how much they weigh using the SI units? As a physics teacher this is my standard question to anyone who feels like they know "all about the metric system," and don't want to review it.  It's important to remember that kg can not be used to measure weight, which is a force.



I thought kg was a measurement of mass, and a measurement of force when applied/plotted against a measure of time?

cheers, Ian


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## Coyote_Physics (Jul 20, 2013)

The SI unit of force is the Newton, which is equal to kg*m/s^2 (i.e. force equals mass times acceleration) to find your weight take your mass in kg and multiply it by 9.81 m/s^2 (gravitational acceleration here on earth.)


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## aarggh (Jul 20, 2013)

Coyote_Physics said:


> The SI unit of force is the Newton, which is equal to kg*m/s^2 (i.e. force equals mass times acceleration) to find your weight take your mass in kg and multiply it by 9.81 m/s^2 (gravitational acceleration here on earth.)



Dammit, thanks for that! There goes the banana cake I was planning on!


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## /// (Jul 20, 2013)

Coyote_Physics said:


> Is there anyone here who knows how much they weigh using the SI units?


~1030 N

:shrug: Not hard.
Anyone schooled on the metric system _should_ be able to answer that.

Edit: oops, I had opened a stack of threads in background tabs, by the time I got to this one there were replies I hadn't seen. Ignore me


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## Coyote_Physics (Jul 20, 2013)

/// said:


> ~1030 N
> 
> :shrug: Not hard.
> Anyone schooled on the metric system _should_ be able to answer that.



Agreed, but yours is the first correct answer I've ever received.


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## /// (Jul 20, 2013)

Coyote_Physics said:


> Agreed, but yours is the first correct answer I've ever received.



That's pretty sad. Are you located in a country using the Imperial system?
It's only slightly more difficult converting from pounds to Newtons, but it can easily cause confusion.


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## Coyote_Physics (Jul 20, 2013)

/// said:


> That's pretty sad. Are you located in country using the Imperial system?
> It's only slightly more difficult converting from pounds to Newtons, but it can easily cause confusion.



I am in America, but I generally ask the question to at least one of my classes per year, so hundreds of people have had the opportunity to answer.


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## /// (Jul 20, 2013)

Interesting. So do you know where they usually go wrong?
Are they not converting lb to kg before multiplying by 9.81?

I think this may be where we metric countries may be at a slight advantage, almost everyone already knows their 'weight' in kg.


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## Coyote_Physics (Jul 20, 2013)

For the most part I think that they are unaware that kg is not a unit of weight.  This is probably due to the fact that virtually everything at the grocery store has a label that says something like: Net Weight, 5 lb (2.27 kg).  The few that know what a Newton is are unable to relate it either to pounds or kilograms.

It also doesn't help that some people teach that pounds can be used to measure both force and mass.  In my opinion the concept of a pound mass (lbm) is one of the worst units ever conceived.


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## wildun (Jul 20, 2013)

Here ( "Down Under") in Australia and New Zealand we have to be prepared to work with whatever system is thrown at us and most engineers/tradesmen automatically work with both systems as a matter of course. 
People of my age (70 or so) were trained in the imperial system then the country "officially" changed to the metric system, but the change wasn't complete as we still had to deal with American machines and goods,  converting everything then became the norm and with the advent of calculators this then became no problem at all, so we live with it.
I find that with things like bore and stroke measurements in model aircraft engines is absurd, the bore and stroke are measured in millimetres and the cubic capacity is expressed in cubic inches! and nobody knows how to deal with it. The best advice I can offer on this one is that if you want to convert between ccs and Cu Inches quickly in your head, use a factor of 6. So divide by 6 for ccs or multiply ccs by six for cubic inches - forget the decimal points, this will get you close enough to understanding the conversion. America is now using metric measurements in the automotive and aerospace industries and many others, - China seems to use whatever measurement it feels like on the day! - so the confusion goes on.
As for reading micrometers, sit down and figure it all out (it's not that difficult) over and over till it is imprinted in your brain, don't sell your DTI, it's only a reference or comparator, it can not be 100% accurate unless it is set at the exact angle to the work and who wants to waste time trying to do that!


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## vederstein (Jul 20, 2013)

I think that Farhenheit is a much better measurement for temperature than Celsius.

Both Fahrenheit and Celsius are arbitrary:

For Celsius:  The freezing point of water = 0 and the boiling point of water = 100.

For Fahrenheit:  Freezing point of water = 32 and the boiling point of water = 212.

Here's the difference:

Fahrenheit's scale of 0-100 is easily transferred to the human condition.  0 is just really friggin cold and 100 is really friggin hot.
That compares much better than to Celsius where -10 if really cold and 45 is really hot.

So in normal conversation, Fahrenheit is better because it easily translates into a 0-100% scale from cold to hot for a human's existence.


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## gus (Jul 20, 2013)

It took a young kid quite some time in primary school to learn,(Was poor Gus in 1950)
Pound,shilling,pence,farthing.
Inch,foot,yard,furlong,mile,league.
Sq ft, sq yard,square mile,acre.
fluid ounce,cu.inches,cu.feet. cu. yard.
Ounce,pound,hundred weight,tons etc.
pound force,foot pound,pound foot.
Did Applied Thermodynamics in Imperial. Was fortunate I joined Ingersoll-Rand,USA and was using Imperial units for 32 years to quote air compressors,gas compressors and water pumps.

Took me some time to get use measuring  in mm when machining. Found it convenient to use metric screws.Saved me all the trouble looking for nuts and bolts in  BSW  BSF  BA  NC NF etc. Not too many shops stock imperial fasteners. Also had a hard time using/reading metric micrometers.I am quite competent now. 
I refuse to use metric dial gage. I am still with Imperial Dial Gages.Been aligning pump couplings with Imperial Dial Gage.

Actually the metric system is simple/easy to use compared to the 1/32 1/16  1/8 1/4 1/2 5/8
3/4 inch. They have no pound shilling pence farthing. No oz lb cwt ton .

After 40 years with Imperial , it was hard to go metric. We were bias.

Getting to like using Centrigrade.

Still very confused.


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