Thanks for the comment mklotz! The vernier for the metric system is very simple to make, but the vernier for the English system is a little more laborious. When I have time, I will make the fractional inch markings too!
As everyone knows, for the English fractional system, the following divisions can be used: a dash on the fixed scale = 1.5875 mm (1/16 ") and a dash on the vernier = 0.1984 mm (1/128") . In this case it is already more complicated to get exactly four decimal places on my machine. For now I prefer to work with the metric system ... As the markings are very close in the English system, the fixed scale and the vernier are not so readable. If you can make fine graduations you can improve the visualization a little ...
Last edited by machining 4 all; 11-24-2020 at 12:40 PM.
Personally, I think a vernier on an inferial scale would be the height of idiocy. The average high school graduate can't add 1/2 and 5/8 mentally; how is he going to handle 7/16 + 9/128?
If one insists on using inferial, get a metric vernier and a cheap calculator with which to convert the readings.
For people who are not used to it, more time is really needed to take the readings in the English system. In my case, the English system is useful for selecting approximate drill bits for drilling before tapping. In fact, inch drills are usually cheaper than millimeter drills. But I don't see many problems, it would just be a matter of getting used to it ...
It is a pity that people have lost some old habits. When I was at school I loved math, I loved operations with fractions (minimum common multiple). After I got older, I started to like derivatives and integrals ...
Today young people are slaves to cell phones ... If the cell phone goes bad, the day is unproductive. The hobbyists are on the way to extinction ...
Last edited by machining 4 all; 11-24-2020 at 04:01 PM.
An example of designing an inferial vernier...
Say each inch on the main scale is divided into eighths.
You want each increment on the vernier to represent 1/32
Since one division on the main scale represents 1/8 = 4/32, the vernier scale will need to have four divisions.
Say you want the vernier scale to span 1 - 1/8 = 7/8 inch. Then each division on the vernier will need to be
(7/8) / 4 = 7/32 inch
and a typical measurement would go something like this...
7 little spaces on the big scale (7/8) plus 3 on the vernier (3/32) = (28 + 3) /32 = 31/32.
Can you imagine the average innumerate shop worker getting that right?
I perform the fractional inch readings using a formula, which would look something like this:
(number of divisions before the zero of the vernier x 8) + division that coincided with the vernier. Then I assume a denominator equal to 128 and simplify the fraction found (when it is possible to simplify). Example (see photo):
[(6 x 8) + 4] / 128 = 52/128 "= 13/32"
This method is certainly known to everyone, but it is not instantaneous like reading in millimeters.
I've got a imperial vernier caliper like machining 4 all shows above, and I use all the time. I absolutely love it. Probably the single most used measuring tool in my shop. I got it at HF for something like $10 or so many years ago. In fact, it's gotten a bit long in the tooth, and I haven't had luck finding one (not that I've looked that hard) to replace it. HF doesn't seem to have them any longer.
For most everything I do (primarily fabrication), metric is nothing but compounded frustration, particularly when it comes to fasteners. Yes, the unit conversion math is vastly better, but that's about it. And, if I need accuracy, I'm not concerned with fractions anyway. Nominal is never accurate anyway, and decimals work the same regardless of the unit system.
Thanks for the comments Baddog! In my opinion, the best system is the one that you are most used to using, whether metric or English. It is the same situation with tools, some prefer to manufacture them, others prefer to buy them. So, what is the best solution? It is certainly the one that solves your problems!
Last edited by machining 4 all; 11-25-2020 at 05:38 AM.
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