Installing a Cutting Tool
Lathe cutting tools are held by tool holders. To install a tool, first clean the holder then tighten the bolts.(2.11MB) (6.72MB)
The toolpost is secured to the compound with a T-bolt. The tool holder is secured to the tool post using a quick release lever.(1.99MB) (6.35MB)
Positioning the Tool
In order to move the cutting tool, the lathe saddle and cross slide can be moved by hand.(860kB) (2.91MB)
There are also power feeds for these axes. Procedures vary from machine to machine.
A third axis of motion is provided by the compound. The angle of the compound can be adjusted to allow tapers to be cut at any desired angle. First, loosen the bolts securing the compound to the saddle. Then rotate the compound to the desired angle referencing the dial indicator at the base of the compound. Retighten the bolts. Now the tool can be hand fed along the desired angle. No power feed is available for the compound. If a fine finish is required, use both hands to achieve a smoother feed rate. 2.05MB (6.54MB)
The cross slide and compound have a micrometer dial to allow accurate positioning, but the saddle doesn't. To position the saddle accurately, you may use a dial indicator mounted to the saddle. The dial indicator presses against a stop (often a micrometer as shown in the clip). 1.29MB (4.25MB)
Feed, Speed, and Depth of Cut
Cutting speed is defined as the speed at which the work moves with respect to the tool (usually measured in feet per minute). Feed rate is defined as the distance the tool travels during one revolution of the part. Cutting speed and feed determines the surface finish, power requirements, and material removal rate. The primary factor in choosing feed and speed is the material to be cut. However, one should also consider material of the tool, rigidity of the workpiece, size and condition of the lathe, and depth of cut. For most Aluminum alloys, on a roughing cut (.010 to .020 inches depth of cut) run at 600 fpm. On a finishing cut (.002 to .010 depth of cut) run at 1000 fpm. To calculate the proper spindle speed, divide the desired cutting speed by the circumference of the work. Experiment with feed rates to achieve the desired finish. In considering depth of cut, it's important to remember that for each thousandth depth of cut, the work diameter is reduced by two thousandths.
Turning
The lathe can be used to reduce the diameter of a part to a desired dimension. First, clamp the part securely in a lathe chuck (636kB). (2.91MB)
The part should not extend more that three times its diameter. Then install a roughing or finishing tool (whichever is appropriate). If you're feeding the saddle toward the headstock (as in the clip below) use a right-hand turning tool. Move the tool off the part by backing the carriage up with the carriage handwheel, then use the cross feed to set the desired depth of cut. In the clip below, a finish cut is made using the power feed for a smoother finish. Remember that for each thousandth depth of cut, the work diameter is reduced by two thousandths.
(click here for video) 821kB
Facing
A lathe can be used to create a smooth, flat, face very accurately perpendicular to the axis of a cylindrical part. First, clamp the part securely in a lathe chuck (636kB). Then, install a facing tool. Bring the tool approximately into position, but slightly off of the part. Always turn the spindle by hand (248kB)before turning it on. This ensures that no parts interfere with the rotation of the spindle. Move the tool outside the part and adjust the saddle to take the desired depth of cut. Then, feed the tool across the face with the cross slide. The following clip shows a roughing cut being made; about 50 thousandths are being removed in one pass. (click here for video) 2.35MB If a finer finish is required, take just a few thousandths on the final cut and use the power feed. Be careful clearing the ribbon-like chips; They are very sharp. Do not clear the chips while the spindle is turning. After facing, there is a very sharp edge on the part. Break the edge (205kB) with a file.
Parting
A parting tool is deeper and narrower than a turning tool. It is designed for making narrow grooves and for cutting off parts. When a parting tool is installed, ensure that it hangs over the tool holder enough that the the holder will clear the workpiece (but no more than that). Ensure that the parting tool is perpendicular to the axis of rotation and that the tip is the same height as the center of the part. A good way to do this is to hold the tool against the face of the part. Set the height of the tool, lay it flat against the face of the part, then lock the tool in place. (click here for video) 2.45MB When the cut is deep, the side of the part can rub against sides of the groove, so it's especially important to apply cutting fluid. In this clip, a part is cut off from a piece of stock.
(click here for video) 246kB
Drilling
A lathe can also be used to drill holes ac