7 years ago, my brother and I had a 1903 Turkish Mauser we wanted to sporterize, so we needed machine tools.

My brother had worked for years as a machinist for piecemeal pay on non Aluminum aircraft parts that were difficult to produce. He would get a box of metal and a set of drawings. If he could make parts that passed inspection, he got half the money the machine shop received.

My brother had to get over the idea that there are no drawings [Machinists do not trust engineers, like me, that wave their hands and produce no drawings].
He read a book on Mausers by Kuhnhausen and started making tooling.

I had to learn how the machines worked and come to grips with how much stuff I was going to buy:
Lathes
Tooling for the lathes [quick change tool post, boring bars, steady rest, etc]
Mills
Tooling for the mills [ parallel bars, collets, V-blocks, vises, clamp kits, etc.]
TIG welders
Oxyacetylene welder
Arc welder
Metal shapers
carbide grinders
air compressors
bead blaster
granite surface plates
height gauges
115 piece drill sets
pin gauge sets .251-.500"
Depth micrometers

One thing I got for free was a 3 foot high chart from Starrett
There is one on my shop wall and my brother's shop wall:
Starrett Inch/metric tap drill sizes & decimal equivalents
http://catalog.starrett.com/catalog/catalog/groupf.asp?...=Feature&GroupID=273


When my bother told me to get those charts, I did not think they were necesarry.
But now when I work in my shop, I often have to look up at that chart.