Model Tapered Pipe Thread Tap Drills

[Bogstandard]

Marv is exactly right when he mentions a collection of measures of convenience.

You have to remember, when these measurements were first being brought into existence, the local serf most probably spent his whole life within a couple of miles of his hovel, ten miles away was the end of the world.
Ounces just might have been a way of describing how something could be divided.
In those days, a penny was most probably the smallest national currency, a years wages to a serf. So they actually cut the coins into pieces, so they had small enough currency that they could work with. Divide a penny into the smallest parts, and the most manageable size would most probably be 1/16Th's. So this might have been used as weight measures as well, divide a pound into 16 parts (ounces).
A trader then goes to another hamlet 10 miles away and starts to use the system there, very soon you have the country using a 'standard' system. Right or wrong, it was correct for the time.
Over the millenia things come in and out of fashion, and so you end up with what we have today, what will it be like in another hundred years, another super system?

It is no use arguing over the metric/imperial system, no one will ever win. Just make do with what you are happy doing, and wait for the brains above to give us another system that will confuse us even more.

John

 

[Stan]

The method the US used to identify electronic components also defies logic. I guess the first vacuum tuba made was called a number '1' and all other manufacturers of that tube also called it a number 1 unless they made a production change and then it became a 1A or 1B. That worked until someone decided he didn't like that system and he started a new system whereby there was at least some information in the number. That didn't last long until multiple new systems (some better and some worse) came along.

In the early 1950s. transistors came on the market with the opportunity to create a sensible numbering system. Instead we got "Let's start with number one again". That quickly evolved into every producer using his own numbers, even for identical items.
This created a market for books that listed basic numbers and then the data on how each manufacturer differed from the basic

With the development of micros and high density chips everything became propriety and when you need a replacement part you order the US manufacturer's number and then wait for months for it to arrive from a Far Eastern factory.

Remember the quote about history repeating itself.

 

[cfellows]

Just a follow up to let folks know I got my tap and die from PM Research. Boy that was fast! I ordered them on Wednesday and received them on Friday. I also bought a couple of "trees" of unfinished pipe fittings in brass. At $6.75 each, I think they were a pretty good deal. The pipe nipples will be made from 1/4" diameter rod. Here's a link to a picture at PM Research's web site:

http://www.pmresearchinc.com/store/product.php?productid=3238&cat=39&page=1

Chuck

 

[mklotz]

Those pipe fittings are really neat. I used them on my (PMR) boiler and I always get comments on how realistic they look.

Holding the elbows to drill and tap them is a bit tricky, though.