Compact CNC Lathe

Jan. 2026

It's making chips! I had just enough time to get the machine running for the first time and turn a handful of test parts before driving back to Chico for the spring semester. I finished the spindle assembly, dialed in all the axes, and loaded up some test material. I didn't have time to wire in the encoders for threading, so unfortunately, no threading demo as of yet.

All the toolpaths for the pawns were programmed in Fusion 360. I picked relatively conservative feeds given that the lathe is currently rolling around on some IKEA wheels and not bolted to a concrete slab. This is why there is some shaking in the video: the whole machine is rocking back and forth!

My plan is to continue developing the machine and hopefully bringing it to a polished state. Full enclosure, (mist?) coolant, tool changer, the works.

Planning

In 2023, I began selling mechanical pencil components, each one meticulously manually machined. I quickly began to struggle to keep up with demand. As I made my first hundred sales, it became increasingly evident that automation would enable me to increase productivity and, consequently, volume. After researching my options thoroughly and receiving quotes from several job shops, I decided that the best course of action would be to construct a teeny purpose-built lathe. This, of course, is a ludicrous decision that only a 17-year-old high school student would make.

Spec.

My design had to work around several key constraints. The new lathe would have to:

Operate on a standard 120V outlet and draw no more than 2.4 kW.
Fit through a standard 30" door.
Easily fit in a small SUV.
Safely contain coolant, chips, and (some) noise.

In addition to the stringent constraints, the lathe would also require sufficient tooling to turn my pencil components. Having manually machined over three hundred components, I understood that the new lathe must possess:

A threading tool
A turning and grooving tool
2 twist drills

Based on my tooling requirements, I opted to design a machine equipped with a gang-tool system, where multiple turning tools are arranged side by side on a T-slot plate. Consequently, the X-axis, or cross slide of the lathe, would require a considerable travel distance to provide adequate clearance for each tool.

Initial Design

The availability and price of components significantly influenced the design of the new lathe. I prioritized securing the most expensive and challenging-to-obtain components first. By “locking in” key components, I would save time and money but sacrifice design flexibility.

Most notable among the early acquisitions were:

A heavily modified mini-lathe spindle with a pair of appropriate angular-contact bearings.
An 80mm-wide ballscrew actuator with two large bearing blocks and a ⌀20mm ballscrew.
A 0.7kW servo motor to drive the spindle.
A three-inch-square aluminum extrusion to serve as the machine base.

An 80mm ballscrew actuator packaged in a wooden shipping crate — A bit of low-balling on eBay got me this beauty for a hair under $200. Weird sticky dust from sitting around for years, but otherwise functionally new.

A long aluminum frame with a black slide bolted to the top — Several of the "locked in" components are visible in this image.

Working around these components, I designed a frame and motion system. For surfaces that I knew required relatively flat surfaces, I opted for aluminum tooling plate, which is inexpensive and readily available. I also employed laser-cut mild steel where tolerances were less critical.

Initial Fabrication

During the first few months of 2024, I gradually machined, assembled, and tested the frame. Once the frame was securely bolted together for the first time, I partially disassembled it and filled the large hollow sections of the aluminum framing with epoxy granite. The epoxy granite was designed to dampen vibrations and stiffen the frame.

My epoxy granite recipe, admittedly amateur, was based on best practices. The final mixture consisted of 80% granite by weight and 20% epoxy. For the granite, I used a combination of coarse granite pebbles and DG. Although sifting, washing, and drying the granite was time-consuming, the casting process itself was quick and straightforward.

At this stage of the project, the scope was getting out of control. Recognizing this, I deliberately set aside the enclosure design until I had an operational machine to test.

Moving Forward

This project is still ongoing as of January 2026. Here's a breakdown of what's been completed, what's currently being worked on, and what's next:

Complete	Ongoing	Planned
Machine Base	Gang Tool System	Enclosure Design
Motion System	Rotary Encoder for Spindle	Coolant System
Control Cabinet
Limit Switches for all Axes
First Chips.

A belt-driven motor and spindle assembly mounted above the lathe slide — I had these pulleys modified to accommodate my goofy combination of "spindle motor" (repurposed 750W servo) and spindle. Getting custom drive belts is so cheap! It was single-digit dollars each, and I only bought two. Probably helped that I got the pulleys from the same vendor.

A partially assembled lathe cross slide — Check out those one-of-one custom fasteners! I turned down a bunch of round-head Torx screws because it was what I could get on Amazon with next-day shipping.

Several electronic components wired together atop a metal panel — I built this control cabinet before I had figured out that terminal blocks and other low-voltage control wiring accessories are functionally commodity items and readily available at bargain prices in the DigiKey and AutomationDirect catalogs. Please excuse the use of no-name mystery stuff.

An open white control cabinet showing its wiring, drivers, and power supply — My choice of controls was perhaps too efficient. I really don't like how sparse my semi-finished cabinet looks. Maybe I'll just have to keep adding new stuff until it feels full.

A black-and-white dog resting beside the lathe in the workshop — Tucker! Excellent shop dog, and very excited that everyone is on the floor where he hangs out.