Machines tools and equipment
The machines and equipment you use to manufacture and inspect precise parts
An accurate part requires the right machines the right tools and reliable measuring equipment. The technique behind them is not an appendix to the job — it is the craft. Here are the tools you work with and the concepts you need to know.
§The machining machines
The basic machines remove material each in its own way. The lathe rotates the workpiece and feeds a tool against it so round parts are shaped. The milling machine instead rotates the tool and moves the workpiece so surfaces notches and edges can be processed. The drill makes holes and the grinder gives fine dimensions and smooth surfaces. Today many of them are computer-controlled (CNC) so a programme controls movements precisely and repeatably.
§Cutting tool
The machine stops automatically
§Measurement of critical dimensions against drawing
You cannot produce precisely if you cannot measure precisely. Therefore the measuring tool is just as important as the machine.
| Measurement of core temperature and room temperature must be included in self-control. | Used for |
|---|---|
| Sliding gauge | Quick measurements of length, diameter, and depth with good accuracy |
| Micrometer screw | Very accurate measurements, typically of thicknesses and diameters |
| Dial gauge (comparator) | Comparing dimensions and inspecting deviations and runout |
| PLACEHOLDER_97 | Check quickly if a measurement is within limits (good/not good) |
| Protractor | Check angles and straightness |
§Tolerance — the allowed clearance
No part can be made precisely to the exact dimension and it does not need to either. The drawing specifies a tolerance: how much the dimension can deviate and still work. A tolerance of a few hundredths of a millimetre is common in fine mechanics. Understanding tolerances is central: a part within tolerance is good — even if it is not quite on the exact dimension — and a part outside is scrap regardless of how nice it looks.
§Surface and finish
Beyond the measurements, a drawing often sets requirements for the surface: how smooth or rough it must be. The surface affects how the part fits together with others, how well it tolerates wear and how it looks. It is controlled by which tool and speed you use and any post-processing such as grinding or polishing.
§Materials
Fine mechanics works with many materials — different metals and plastics — and each has its own properties: how hard it is, how it cuts and how much it expands with heat. A material that is easy to machine behaves differently than a hard one and you adapt tools, speed and feed according to it. Knowing the material is part of hitting the target.
“The right machine and the right tool make the part. The right measuring tool proves it's good.”
— Professional view on equipment in precision mechanics.