Have you ever wondered how all the things you use on a daily basis were made? Just look around you right now: you might see a computer monitor, mouse, keyboard, briefcase, chairs, desk, lighting, light switches, windows, doors, phone, cell phone, pens, paper clips and on and on.
Most of the time we just take these things totally for granted and only notice if something goes wrong.
If people had to spend a week or so doing what other people do, I think we would all be a lot more tolerant and compassionate. This is especially the case when it comes to precision measurement.
Injection mold makers, tool and die makers, aerospace machinists, micro precision machining personnel, and medical precision machining are all examples of jobs that demand extremely close tolerance work.
How close is close? When the layman sees a dimension such as .0002 in./.005 mm, they realize that is pretty small, but just how small is it? Imagine a cigarette paper, which is actually .0008 in. thick.
If you could split the paper in the thickness once it would be .0004 in., split it again and you have .0002 in./.005 mm thickness. That is a typical tolerance for toolmaking in general.
The type of measuring tool makes all the difference, as does that accuracy of the machine doing the work. It is maddening to work with such tolerances with old, inaccurate equipment, yet that is rather common in many shops. Oddly, many developing countries have newer equipment than in the USA.
Some of the precision measuring tools
- Dial indicators. Starrett, Brown and Sharpe, Tesa, Mitutoyo, Interapid, and Mahr are some common brands.
- Precision micrometers. Starrett, Brown and Sharpe, Mitutoyo, Tesa, Etalon, and Helios are some of the better makes.
- Granite surface plates. Starret, Rock of Ages and Standridge are all top companies
- Optical comparators are extremely useful for checking angles, radii and dimensions. Scherr-Tumico, Mitutoyo, OGP, Nikon, Micro-Vu, and Dorsey Metrology International are all good companies.
- Pin gages. These simple tools are workhorses of the shop. Meyer, Starrett, Vermont Gage and Deltronic are all good sources.
- Gage blocks are some of the most useful precision measuring tools to be found. They are incredibly simple, but very accurate. Good companies include Starrett, Webber, Mitutoyo, CEJohannson and Do-All.
- Coordinate measuring machines. Nearly every precision CNC machine shop in the world has or has access to a CMM. This is useful for inspection, gaging and staging of workpieces. There are many great suppliers, including Starrett, Brown and Sharpe, Zeiss, Mitutoyo,
