A long time ago when PTFE {Teflon] tape became popular as a replacement for sealants like Rectorseal and similar products I went to a class at MIT being conducted by Dupont to promote their tape. The engineer from MIT that introduced the speaker began by saying that tapered threads do not need sealant, by design. But only if manufactured to exact tolerances on both male and female fitments. In the real world machine tools get duller and the machines themselves get worn. But if fitments are bought from a reputable manufacturer the biggest advantage for using a thread sealant is not to seal but to lubricate for a tighter fitting. If one is buying threaded parts from the lowest bidder having solids to fill in the flaws from the manufacturer is an advantage. Someone asked what to do if a fitting leaked after using PTFE and the engineer said slobber a bunch of Rectorseal on top of the tape, the solids should fill in the gaps. If that bothers you go work on the Apollo space program, thread sealant isnât used as much. Itâs a QC thing.
The hardware store I frequent finally are beginning to stock metric/inch measuring tapes. I picked up an 8m/26ft one today.
NPT should be the global standard as it works.
Metric world is cursed by going down the BSP route
Senior British and Commonwealth naval officers were very particular on brevity with their signals and sometimes things went wrong. There was a book called âMake a signalâ where many, including humorous ones, were recorded.
One of my favourites was a flag lieutenant was instructed to organise the admiralâs laundry. He sent without further editing a signal â have admiralâs woman attend shipâs arrivalâ.
Aghast after reading the hard copy of the signal he sent a further signal. â Between admiral and woman insert washer.
Was always taught never to use tape on hydraulics and fuel systems, never did luckily by my time its was a paste in a tube.
The yellow tape is OK .
Worst misuse of tape I saw was teflon tape used on pneumatic instrumentation compression fittings. That stroke of ignorance cost a lot of money.
. Measuring systems in the U.S. have evolved such that for most people having to convert is not very common so daily life is not the hellscape some may imagine. Many rulers, measuring cups speedometers, barometers etc are marked with both.
A shopper grabbing a two liter bottle of soda off the shelf is not going to bother to convert.
For tasks like cooking most recipes match the tools found in the in the kitchen. In the shop tools sets come with both metric and customary. For most cases trial and error works as do adjustable wrenches, no need for any conversions.
Other tasks are entirely metric, land navigation for example can be done with a rough sense of the size of a meter (about a yard) USGS topo maps and a GPS set on UTM.
For conversions that are common it doesnât take long to to have memorized or roughly estimated; meters to feet, miles to kilometers, pounds to kilograms, liters to gals and so forth.
Be more efficient to use metric only but for most people in every day life having two systems is rarely an issue.
My go-to conversion site for cooking:
Cheers,
Earl
I grew in the right country at the right time so happy to use both systems ( plus us gal etc )every day and still do, hence notice when either doesnt work.
Whats the metric for pressure, cant decide so there are several
What the metric for force, cant decide so there are several
Love UTM its metric and implemented by US army engineering corp.
Almost all USGS topographic maps produced after 1977 show UTM tick marks on the sides of the map (or a full-line grid) every 1,000 meters. Some maps, including all those produced after 2009 (US Topo maps) include full UTM grid lines.
Example:
PS> The height is still in feet though
Except for the barometer I havenât encountered SI pressure units outside a classroom but did figure out a good conversion.
I recall from school standard pressure (1013.25 mb) is 14.7 psi
Thatâs close to one bar which is 1000.0 mb or 14.5 psi.
10 bar = 1 Mpa.
From there a small step to 1 Mpa = 145 psi.
The engineers on foreign going deep sea ships use the units bars for pressure.
In aviation, standard atmospheric pressure is given as 29.92 Hg (inches of mercury). I doubt thereâs a country or industry that is dependent on a single system of measurement across the board.
I can deal with BAR as its common sense, its one atmosphere for a diver and your radiator cap.
flying is 50 :50 altitude is feet, distance is metric to keep the frogs happy
In the US, itâs altitude in feet and speed in mph to keep motorists happy as well as speed in knots and distance in nautical miles to keep sailors happy.
Yes, approximately, 1 atm = 1013.25 mb.
The worldwide Airport METARs, distributed by aviationweather.gov, send:
- temperature and dewpoint in °C + °F
- pressure in inches Hg + mb
- winds in MPH + knots + m/s
- visibility in sm + km
- altitudes in feet AGL
Nautical miles tie into latitude, as you know âa minuteâs a mileâ, that is a minute of latitude is (approximately) a nautical mile.
Meters ties into latitude as well but in a less convenient way.
90 degrees of latitude â10,000,000 meters.
10,000,000 meters / (90 * 60) = 1851.9 meters, but defined as 1852 meters / mile
Some foreign weather forecasts use m/sec for wind speeds,
1 m/sec is 1,94 kts or about 2 knots.