Today's 'maker' is fortunate enough to have many options available to them that someone 20 years, or even 10, ago did not have. Tools such as 3D CAD modeling, home 3D printing, and rapid online CNC machining are all easy to acquire and/or use.
However, one piece of kit that perhaps does not get the credit or attention it deserves is the lowly hand-operated metal lathe.
Rapid online CNC turning and milling services from suppliers such as Protolabs, Xometry, and e-Machine Shop are indispensable for making 'real' prototypes quickly with metal parts. That said, there are many parts that can be made quickly and cheaply at home. Even the most simple turned metal part can cost ~$100 when ordered at qty=1. This is where a manual lathe comes in to play. Simple parts can be cut quickly and cheaply and expensive custom CNC-cut parts can be modified.
I have a Craftsman/Atlas 618 lathe which I estimate was manufactured in the early 1960's. I found it on Craigslist for $600 complete with maple work bench. It has since been upgraded with a variable-frequency-drive, and quick change tool set.
- Variable Frequency Drive -- for changing RPM quickly on the fly without changing belts
- Quick-change tool set -- for rapid changing of cutting tools. This is INDISPENSABLE. Not only can you change a cutting tool quickly for the next operation, they are all pre-indexed and ready to go.
- 3-jaw chuck -- for rapid work holding of material that doesn't requiring indexing (cutting new parts)
- 4-jaw chuck -- for accurate work holding of irregularly-shaped material or to minimize runout when re-machining an existing part
- Dial indicator -- used primarily for measuring runout and accurately setting a 4-jaw chuck
- Machining attachment -- although this can be used for basic 4-axis machining operations (with an end mill on the headstock spindle), it is most useful for locating drill guide bushings when making hole patterns. The headstock has 60 detent pin positions for creating axisymmetric hole patterns.
The downsides of the 618 are:
- As a desktop lathe, it doesn't have the rigidity of a larger lathe. This limits maximum cutting depth/speed and it takes great care to hit 0.025mm (0.001") tolerances.
- It is standard. I design everything in metric with as few metric fastener types and sizes as possible. I have to calculate and list all basic dimensions and tolerances by hand in inches before cutting.
I am happy with my Atlas 618, but in the future I may trade it in for a lathe which is larger, newer, and metric.