The Machinist and Machining Tools 101
Schaus-Vorhies Manufacturing (SVM) takes on several unique, custom projects. These projects are designed and constructed from the ground up. Usually, the projects require parts we have to make and assemble on site. That calls for not only top-notch engineers and welders, but it also needs a position we haven’t talked much about yet; a machinist and his or her tools.
Once upon a time, a machinist would typically build entire machines from the ground up. However, in the modern-day, most parts and machines are mass-produced. Still, custom pieces and older machines that no one makes parts for means that machinists are in high demand. What exactly does a machinist do, and what are some of the tools he uses to get the job done?
A machinist carves metal, just like a woodcarver shapes wood or a stone cutter makes sculptures. A machinist can take a hunk of raw metal with a given design and turn it into whatever is needed. It can be something as simple as a fire poker’s handle or gear for a helicopter rotor. To be a machinist, one must have high attention to detail, a more than ordinary share of patience, and a working knowledge of a variety of high precision tools for cutting and measuring.
Like any crafting, the first thing to do is to measure the material. Several different tools will be needed to ensure that the right measurements to get the job done. Below are a few of them and a description of their main uses.
Dial caliper: The dial caliper is arguably the most versatile of the many tools in the machinist’s toolbox. Think of it as a fancy ruler. They will have at least one sent of pointy jaws for measuring the outside of an object. Many also have another set used to measure an object’s inside, such as a small container or the inner diameter of a pipe. The outermost jaw is fixed while the other slides along a metal bar with the aid of a knurled knob, usually operated with the thumb. Some will have marks like a ruler. Others, a simple gauge. It is increasingly common that digital calipers will display the measured length on screen, making it easy to get accurate measurements down to the thousandth of an inch. If you need to verify a part came out the way you need it to or check the length or width of a part before making a duplicate, it is likely to be one of the first tools you grab.
Machinist scale: The machinist scale is just a fancy ruler. Used for small measurements of six inches or less, these scales have accurate marks down to a sixty-fourth of an inch. If something needs to be checked quickly and doesn’t need to be at aerospace levels of tolerance, this is a convenient tool.
Micrometer: Most micrometers are used for measuring the outer diameter of an object, such as a pipe or a shaft. Smaller than a dial caliper, the micrometer looks similar to a C-clamp. The arch of the ‘c’ portion allows the machinist to measure around an obstruction in ways that might not be possible with a dial caliper. Inside micrometers are effectively used to measure the inside of a pipe or a nut. They are operated by turning a nob at one end until the contact surface hits the object being measured and can provide accuracy up to ten-thousandths of an inch. They can also be tricky to read.
Snap Gauge: These don’t provide a measurement on their own. These are a T-shaped tool, with a twist knob at the long end and two cylindrical posts at the top portion. The top of the T is inserted into the pipe, canister, or other objects to be measured. Holding its level, the knob on the end is twisted, causing the posts to snap to the pipe’s inner end. The knob is then twisted back to lock the posts in place. Once removed from the object being measured, the posts’ length is measured with a dial caliper.
All of these tools require a degree of training and skill to use effectively. For beginners, it can be challenging to get the right feel for the various instruments. However, the experienced machinists at SVM have the experience and skill needed to get accurate measurements every time. Next time, we’ll look more at the many tools that our machinists use to make any custom order that might come our way.