# Operating a Milling Machine

Grizzly G0759

## Permanent Materials

- G0759 Milling Machine and Milling Vise
- Collets
- HSS Mills
- Drill Chuck and Drill Bits
- Die and Tap Sets
- Edge Finder
- Dial Indicator
- Parallel Bar Set
- Digital Calipers

## Consumable Raw Materials

- Al 6061 1 1/8" x 1 1/8" Bar Stock

## Activities

### Basic Milling Project

Basic Idea: Make a small 1" Al cube with tapped holes and one face hogged out.

CLEAN UP AREA AFTER EACH LAB SESSION

NOTE: Use the low "L" speed range for most operations (and make slow cuts). The motor has more torque in the low range. Also, don't operate the mill at max speed for more than a few minutes at a time in order to avoid overheating the motor. If you want to operate the mill at high speeds (for finishing purposes), use the high "H" range and turn down the variable speed dial from max (maybe 80% of max value).

NOTE: Only change speed ranges (between "L" and "H") with the machine off.

1. Get a safety demonstration from the instructor or TA.
2. Read the G0759 manual Introduction and Safety sections (pages 2-10) and the Operations section (pages 22-32). You can also view a few of the many good how-to-mill videos on YouTube.
3. Use AutoCAD (on virtual machine on mother in APL) to make a technical drawing of a 1" Al cube with four 8-32 (0.5" deep) tapped holes in the corner of one face (holes positioned 1/8" from edges) and a 1/4" hogged out squarish hole (1/8" border) on the opposite face. If you're new to AutoCAD you can view a few of the many good AutoCAD-for-beginners tutorials on YouTube. Show drawing to Instructor or TA before moving on.
4. Read the Wikipedia page on machining speeds and feeds. Calculate Spindle Speed with this online calculator. Set the mill's spindle speed to be no more than 3/4 the calculated speed and less than 80% of the maximum G0759's spindle speed.
5. Set up a rough cut of a ~ 1 1/8 length section from the Al bar stock using the band saw - Get instructor or TA approval before making the cut. Clean up metal shavings and put bandsaw and stock back in storage areas.
6. Lubricate the head stock vertical column with a few drops of oil (on each side).
7. Mount the rough block in the milling vise using parallel bars (rough side face up) - Get instructor or TA approval before milling.

Do not push work piece into bit (in any direction) when machine is stopped. Do not take more than 0.020 inches off in any single face or side milling operation.

1. Side mill the rough sides so that they are 1.000" +- 0.003" from their opposite faces.
2. Face mill the other faces such that all faces are 1.000" +- 0.003" from their opposites (use edge finder to precisely locate faces). Get instructor or TA approval before making first side mill operation.
3. Use dial indicator to verify that the faces are parallel to within 3 mils (a mil is one thousandth of an inch).
4. Drill and tap 4 8-32 screw holes at the corners of one face (1/8" in from both faces). Use this drill and tap chart. Discuss this procedure with instructor or TA before attempting.
5. Hog out the face opposite to the tapped holes. Leave 1/8" border and hog to 1/4" depth (make the process easier with a pattern of material-removing drilled holes). Discuss this operation with the instructor or TA before attempting.
6. Put all tools back into storage and clean up area.