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Getting Started with Mini Lathe Tooling

Introduction

You have purchased a mini lathe, brought it home and cleaned it up. You are ready to start cutting metal, but find that you didn't receive any cutting tools with the lathe. What else do you need to get started?

This document covers all 7x10, 7x12, 7x14, and 7x16 mini lathes.

If you have a similar small lathe, you might not need the exact part numbers described in this document, but you will need the same type of tools.

We will discuss the tools you will need to perform different operations: turning, drilling, boring, and cutting off.

Quick-Change Tool Post?

Before you start selecting particular tools, you might want to make a decision on whether or not you want to invest in a quick-change tool post. As we describe the various tools, we will show your options for each operation with and without a quick-change tool post.

Quick-change tool posts are valuable in a production environment. You can change the cutting tool, knowing that you can return the tool to the exact same position relative to the work. This is important if you are turning out thousands of identical widgets. In most home shops, this is not important, as we are usually making one or two of a particular part.

But quick-change tool posts have one feature that is important to home shop machinists, and that is height adjustment. You can quickly adjust the cutting edge of the tool to the exact center height of the work. Without a quick-change tool post, you have to shim tools that are too low, and simply can't use tools that are too high.

Some of the tool posts that home shop machinists call quick-change tool posts don't have the "quick-change" feature at all, but simply provide an easy height adjustment.

On a mini lathe without a quick-change tool post you are restricted to using tools with a 5/16" or smaller shank. With a quick-change tool post you can use tools with shanks up to 3/8" (up to 1/2" in some cases). It's only 1/16" difference, but it opens up a lot of options.

Quick Change Tool Post Options

Turning

Turning is the simplest operation on a lathe. It is reducing the outside diameter of a work piece. It's probably the first thing you will do with a lathe.

There are two basic types of turning tools: high-speed steel tool bits, and carbide turning tools.

High-speed steel tool bits start as rectangles of high-speed steel that you sharpen with a bench grinder. A 5/16" high-speed steel tool bit starts as a piece of high-speed steel that is 5/16" square and 2-1/2" long. Before you can use it to cut metal, you use a bench grinder to shape and sharpen the end. There are several standard shapes for tool bits, which depend on the intended use. Here is information on rake and relief angles for high-speed steel lathe tool bits.

Carbide turning tools come in two flavors. There are tool bits with brazed-on carbide tips, and indexable carbide turning tools.

Tool bits with brazed-on carbide tips are relatively economical, but once the carbide tip is worn out, the entire tool bit is discarded.

Indexable carbide turning tools consist of a shank of hardened steel with a small triangle of sintered carbide (called an insert) attached to the end. The carbide insert is factory sharpened with three cutting edges, one at each point of the triangle. When one point becomes dull, you rotate the next point into the cutting position. When all are dull you replace the insert. These turning tools are called indexable because you can change the insert without affecting the position of the cutting edge relative to the work piece.

Cutting Tool Options

Drilling

Another common operation on a lathe is drilling holes on the axis of the lathe.

Drilling on the lathe works backwards from drilling on most other machine tools. Instead of the drill bit turning, the work rotates and the drill bit is fixed in the tailstock. To hold the drill bit you need a drill chuck. The drill chuck attaches to an arbor of the proper size for the drill chuck on one end and for the tailstock on the other end.

Drill Set Options

Drilling an accurate hole on a lathe is a three- (or more) step process. First a very short and stiff drill bit (called a center drill) is used to drill a small starter hole. The stiffness of the center drill ensures that this starter hole is in the correct location. Then a relatively small drill is used to drill a pilot hole. Finally, successively larger drills are used to enlarge the hole to the required size.

Center Drill Options

Drilling Tool Options

Boring

Boring is the action of enlarging an existing hole with a turning type tool. Because you are turning from the inside out, the boring tool is a different form from a regular turning tool.

As with other operations on the lathe, there are several different choices of tools that will do the job. Carbide tipped boring bars are an economical way to get started boring. They come in a set that provides boring bars for different diameters and different depths of hole. Indexable boring bars with carbide inserts are also available.

Boring Tool Options

Cut-Off

Cutting a work piece off of the parent bar of material is a basic lathe operation. Most cut-off tools are too large for the mini lathe. Many of the cut-off tool options are adaptations of larger cut-off blades to the mini lathe.

Cut-off blades are a narrow, but tall cutting tool. The ones used on the mini lathe are usually 1/2" tall, as this is the smallest commercial size. They come in various widths of 5/64" wide (P1X), 1/16" wide (P1), and 0.040" wide (P1N).

Cut-Off Tool Options

Turning Between Centers

You can also turn work without using a lathe chuck. Put a dead center in the spindle bore to support the near end of the work piece. The spindle is machined with a #3 Morse taper in the bore just for this. Put a live center in the tailstock to support the far end of the work piece.

This is what "center drills" are made for. The small drill bit creates a clearance hole. The counter sink creates a 60° hole that mates with the centers in the lathe. Use the 3-jaw chuck and a steady rest to hold the work piece while you center drill both ends.

The lathe dog drives the work piece. Use a long bolt in one of the holes in the spindle flange to drive the lathe dog.

Turning Between Centers Tool Options

Lathe Chucks

The 3-jaw chuck that comes with the mini lathe is the correct work holding device for most work done on the mini lathe. When you want to work on larger work pieces, rectangular work pieces, or work to a precision you can't achieve with a 3-jaw chuck, then another chuck option is appropriate.

4-jaw chucks have several advantages. Because each jaw is independently adjustable, you can center your work piece more accurately than you can in a 3-jaw self-centering chuck. And, you can easily center square and rectangular stock in a 4-jaw chuck.

If you simply want to turn work pieces that are too big for the standard 3-jaw chuck, then a 4-jaw or larger 3- or 4-jaw chuck is in order.

The mini lathe is designed for a 3" chuck. You need an adapter to mount a 4" chuck on the mini lathe. The adapter bolts onto the lathe's spindle flange and provides the larger bolt circle required for a 4" chuck. 

Lathe Chuck Capacities

* Reported by mini-lathe.com.

Lathe Chuck Options

Knurling

Knurling is the process of imparting a non-slip (usually crosshatch) pattern to the work piece. Knurling is sometimes done for decorative reasons, but usually done to provide a non-slip finish to a hand-operated knob or hand wheel.

Knurling Tool Options

Other Accessories

There are many other accessories that you can use with your mini lathe. Following are a few that you might want to consider as you get stared with your mini lathe.

Faceplate

A faceplate allows you to turn work that cannot be held in a lathe chuck or between centers. You clamp odd-shaped work pieces to the faceplate for turning.

Steady Rest

The steady rest supports the far end or a long work piece. Many times a steady rest is used to support the end of a work piece while you center drill it in preparation for supporting it with a live center.

Follower Rest

The follower rest supports a flexible work piece adjacent to the cutting tool to keep it from deflecting away from the cutting tool. The follower rest mounts on the carriage and moves with the cutting tool.

Milling Attachment

The milling attachment allows you to do light milling on your lathe. It replaces the compound rest and holds the work piece. With an end mill in the lathe chuck or an end mill holder in the spindle, you can mill a work piece held in the in the milling attachment.

Spindle Tachometer

The speed at which the surface of the work piece passes the tool bit is important to achieve the best surface finish and highest production. The spindle tachometer provides positive feedback of the speed at which the spindle is turning. Cutting speeds vary by material, type of tooling, and work piece diameter.

Tailstock Turret Tool Holder

Drilling large holes in a work piece is a multi step process. The tailstock turret tool holder provides a way to make this process more efficient. The tailstock turret tool holder holds up to five different tools, making it easy to center drill, and then step drill to a large hole size.

Other Accessory Options

Tooling Packages

We suggest you choose one of the following tooling packages. We design our tooling packages to include everything you need to get started with a new machine. Tooling packages offer tremendous savings over buying individual items, and you know that every part of the tooling package will work with your new machine.

	Starter Kit, Mini Lathe, 5/16" Tool Bits
	Tooling Package, Mini Lathe Premium
	Tooling Package, Mini Lathe, 0XA QCTP

Starter & Spares Kits

To keep your lathe running, we also have a spare parts kit. The kit contains the parts that fail most frequently, including:

• Five GMA-5 fuses
• One 2-speed Intermediate shaft gear
• One 2-speed spindle gear
• One timing belt
• One timing belt motor pulley
• One timing belt intermediate shaft pulley
• Two power MOSFET transistors

Starter & Spares Kit Options

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