INCH CHART BY 128ths

Looks like 22/7 wasn't accurate enough in the other thread, but in this thread it's good enough for government work! Digital significance applies.
 
Accuracy only needs to be what we are capable of working.

Back in HS the lab had power supplies with digital outputs and others with analog.

Setup time with digital was way longer, results same.

The analog needle pointed at the number, digital had a Decimal to allow to .1 volt accuracy.

Did not matter but folks would chase it.

Sent from my SM-G781V using Tapatalk
 
Navy Chief said:
Just don't do drawings in fractions, decimals are decimals regardless if they are inches or millimeters..

But yes I do wish we would just switch over....
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Dimensions in fractions of inches (at least down to 1/16”) are handy for brackets and similar parts that aren’t critical and make sense when working with stock sourced from the local hardware store or home center.
 
tq60 said:
Accuracy only needs to be what we are capable of working.

Back in HS the lab had power supplies with digital outputs and others with analog.

Setup time with digital was way longer, results same.

The analog needle pointed at the number, digital had a Decimal to allow to .1 volt accuracy.

Did not matter but folks would chase it.

Sent from my SM-G781V using Tapatalk
Click to expand...
Analog meters are very useful when looking at trends (think +/-) whereas digital are more for absolute measurements. I sadly sold my HeathKit VTVM (yes, with real Vacuum Tubes) many years ago, but still have a B-K FET Meter (and an EICO Magic Eye signal tracer) for troubleshooting.
 
ChazzC said:
Dimensions in fractions of inches (at least down to 1/16”) are handy for brackets and similar parts that aren’t critical and make sense when working with stock sourced from the local hardware store or home center.
Click to expand...
While I still think in fractional increments, my drawings are always decimal, even if they equal fractional values.
 
I’m more like James (Clough42): I’m not happy unless my drawings include fractions, decimal inches & mm - not necessarily to annoy anyone (that’s just a bonus), but to indicate tolerances and clearly indicate if something needs to be metric, such as metric hardware & hole spacing to match what a part is going to be attached to.
 
ChazzC said:
I’m more like James (Clough42): I’m not happy unless my drawings include fractions, decimal inches & mm - not necessarily to annoy anyone (that’s just a bonus), but to indicate tolerances and clearly indicate if something needs to be metric, such as metric hardware & hole spacing to match what a part is going to be attached to.
Click to expand...

A long time ago I realized that a good drawing should not require the machinist to grab his calculator any more than absolutely necessary. It simply gives him another chance to screw up make a mistake. Since the machines in the U.S. are graduated in decimal inches, with the exception of threads, my drawings have metric dimensions translated to and toleranced in decimal inches. I don't use fractions, two place and three place decimals (±.010 and±.005) are loose enough. The metric system of tolerancing makes me nuts, WTH is H6 tolerance for a 30mm shaft? You have to refer to a chart instead of having the actual numbers on the drawing, which just introduces another opportunity for error. I'm sure in some way it makes sense and possibly simplifies the job for the draftsman, but it doesn't make life easier for the machinist or the inspector. Look at the drawing after the parts are done, the machinist's notes will tell you if it needs to be revised.
 
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