Changing Speeds

The belts in the head of the drill press must be rearranged to change speeds. A chart under the belt cover shows the belt positions needed to make the drill press run at the desired speed.

To change speeds:

1.UNPLUG THE DRILL PRESS!

2.Loosen the belt tension lock knobs (shown in Figure 26) on both sides of the headstock, so the motor is free to move.

Figure 26. Loosening lock knob (both sides).

3.Rotate the belt tension lever counterclock- wise, as shown in Figure 27, to take tension off the V-belts.

Figure 27. Using the belt tension lever.

-28-

4.Locate the desired speed on the speed chart under the belt cover and move the V-belts to the desired V-grooves on the motor, idler, and spindle pulleys.

For Example: As indicated in the speed chart for 670 RPM (Figure 28), a belt combination of A-1.2-2creates 670 RPM.

•The “A-1” refers to the belt position between the spindle pulley and the idler pulley.

•The “2-2” refers to the belt position between the motor pulley and the idler pulley.

Note: Both belts may have to be removed before certain speed changes can be made.

A-1.4-4

 

 

BELT:B-2.4-4

 

 

BELT:

630

6 RPM

670

7 RPM

4

D

4

 

 

 

 

 

4

D

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

C

3

 

 

 

 

 

3

C

3

 

 

 

2

B

2

 

 

 

 

2

B

2

 

 

1

A

 

 

 

 

 

1

 

 

 

1

A

1

 

 

 

 

B-2.3-3

 

 

BELT:A-1.2-2

 

BELT:

1650

10

RPM

2050

11 RPM

4

D

 

 

4

 

 

 

 

 

 

4

D

4

 

 

 

 

3

C

3

 

 

 

 

 

3

C

 

 

 

3

 

 

 

2

B

2

 

 

 

 

 

2

B

2

 

 

 

 

 

 

 

1

A

1

 

 

 

1

A

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 28. Pulley combination for 670 RPM for

example.

5.Rotate the belt tension lever until the belts are tight. Tighten both lock knobs.

6.Close the cover before plugging in the machine.

G7947/G7948 12 Speed Floor Drill Press

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Grizzly G7948, G7947 instruction manual Changing Speeds, To change speeds
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G7947, G7948 specifications

The Grizzly G7948 and G7947 are powerful, professional-grade milling machines designed for precision metalworking. These models cater to the needs of machinists and hobbyists alike, combining innovation with robust features ideal for various milling tasks.

The Grizzly G7948 is a vertical mill with a large working table, allowing users to handle bigger workpieces efficiently. It features a 2 HP motor, providing a spindle speed range from 50 to 3,000 RPM, enabling operators to tackle a wide range of materials and applications. The G7948’s dovetail column ensures stability and rigidity, minimizing vibrations during operation, which is crucial for achieving precision in milling tasks.

On the other hand, the Grizzly G7947 is a versatile combination of a lathe and a mill, perfect for those looking to maximize functionality in a smaller workspace. It also boasts a robust 1 HP motor, allowing for smooth operation with adjustable spindle speeds, enhancing its versatility. The G7947 is particularly user-friendly, featuring a quick-change tool post that facilitates faster tool swapping and changeovers, which is a significant advantage when working on multiple projects.

Both models come equipped with advanced features such as a digital readout (DRO) system that aids in precision measurements. The DRO provides real-time feedback on the machine's positioning, helping eliminate guesswork and ensuring accuracy. Additionally, the machines' power feed for the table enhances efficiency, making it easier for users to execute repetitive tasks without the strain of manual cranking.

Another notable characteristic of the Grizzly G7948 and G7947 is their user-friendly controls, designed with ergonomics in mind. The intuitive layout ensures that operators can easily navigate through the machine’s settings, allowing for quicker setup times and smoother workflow.

Lastly, the sturdy construction of both milling machines means they are built to withstand rigorous use, making them reliable choices for both industrial applications and serious hobbyists. These models exemplify Grizzly's commitment to quality and performance, making them exceptional additions to any workshop.
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