Mixing measurement systems, bad idea, or really bad idea?

MontanaLon

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Being tool poor I am always on the lookout for cheap tools. Today I found them. 2 dial indicators and a test indicator for $10 each. Brand name too. But then I looked close and they are that funny European measuring system that will never catch on. M m m m m metric. Now I need to drink something to get the taste out of my mouth.

So, avoiding the debate on which is the better system, (we all know it is the inch anyways) my machines have knobs and graduations in inch and I don't see a DRO in the future any time soon, how bad an idea is to mix inch and metric? I mean, other than the loss of money I will suffer when they finally admit defeat and convert back to the imperial system, what ill could I suffer by buying these m m m m metric tools and putting them in the bottom draw of the tool box? I mean who knows, someday I may actually need to measure something to .02 of the cube root of the volume of a gram of water. But what are the chances of that? I suspect they are the cause of spontaneous shop combustion but have no proof. Seriously, they knock the imperial system as being difficult to convert and based on something as arbitrary as the measurement of body part of a man who rose to power through divine means. They based theirs on what they imagined would be a round fraction of something they had no way to accurately measure.

But seriously, will cats and dogs live peacefully together if I give these tools a home? Or will chaos consume my meager shop as I furiously multiply divide by 25.4 and wonder why my parts never measure up to spec?
 
98.5% of dial/test indicator use only involves the zero mark. It's seldom that you actually try to measure something with an indicator, unless you're doing something like aligning a drive shaft with a motor.

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So long as you dont forget which system you are using and keep things consistent I dont see how it would hurt!
 
Haha. As said, when using indicators for measuring runout it doesn't really matter. As far as using both systems for measurement, do whatever is comfortable for you. Lots of people can & do work with both.

Me personally, I use imperial for measurements & cuts, not just with metal. If I need to machine something with metric measurements I convert to imperial even though I have DROs (and digital calipers & mics) where I can switch to metric. It's just what I'm used to & comfortable with. Although I use 25.4mm to convert all the time, I'm lost when it comes to picturing metric dimensions. Like a couple of thou or 100 thou of an inch I can picture the size. But when it comes to a tenth of a MM or whatever I have no clue, I'm just not used to it.

But with fastener heads I can tell if it's a 10, 12, 14, 17, 19mm etc cause I'm used to it, I used to work on import cars. Speaking of fasteners, although I'm an imperial guy, I prefer to always use metric fasteners, I hate using imperial fasteners. I'll only use imperial fasteners if whatever I'm working on already has imperial fasteners. I don't like to mix metric & imperial fasteners for something I'm working, it's a pet peeve of mine. But here in the US, specialty screws are more commonly available in imperial so sometimes I don't have a choice

But when single pointing threads & making something from scratch where it doesn't matter if the thread is imperial or metric, I prefer to single point with imperial threads. I know I'm weird. Although I agree that the metric system is a better system, I'll always be an imperial guy unless the US fully converts over one day which I doubt will happen in my lifetime.
 
I have not had to use the metric system yet, and do not plan to change, at age 74+. Likely the metric system will not be adopted in the USA for a long time yet, if at all.
 
I have DROs on the mill and lathe. It is pretty much immaterial which system is used, and it's very easy to mix. For example, adding the DRO to a mill, it's likely that the mill measurements are imperial yet the mounting holes on the reader are defined via metric measurements.

So there is no doubt about it, you need both. Dial indicators, as has been said, are for the most part "indicators", not "dial measurers".
 
If you are going to send a probe to Mars, don't forget to convert English to metric. This is what NASA did a few years back, it only cost a little over a hundred million bucks.
 
USA will certainly change to metric in the near future. All other english speaking countries have changed. So much in USA is already metric . Your money, all scientific and medical measurement has been metric for some time. If you have a close look at all your imported lathes and mills etc, they are built as metric machines and just have an imperial leadscrew fitted and a couple of gears changed to make them work in imperial.

All your imported vehicles are metric, so mechanics already have to deal with both. Your speedo's are in metric miles, they measure tenths of a mile not yards or feet. Even your micrometers are metric as in 1000th inch.

Gradually you will have to change, but it will probably be more by default and stealth, than actually a planned changeover like we did here in Australia. NZ and UK also did similar.

Once you get used to it metric is much easier and quicker, I learned in imperial until I was about 20 then I had to learn metric now I'm ambidextrous and apply work in both and easily jump from one to the other.
 
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