SKIL 3320 Drill Press Belt: What Owners Should Check Before Buying or Repairing

The SKIL 3320 is a 10-inch, 5-speed benchtop drill press that was widely sold through home centers and has since been discontinued in North America. The belt is the most common maintenance item on any step-pulley drill press, and on the 3320 it is a specific size that owners need to identify correctly before ordering. Getting the belt right means the machine runs smoothly and at the right speeds; getting it wrong means a belt that slips, runs hot, or does not seat in the pulleys. This guide covers exactly what to check.

The SKIL 3320 uses a standard V-belt drive system with a multi-step pulley on both the motor and the spindle. The belt is an FHP (fractional-horsepower) V-belt in a specific length and section (width). The exact size depends on the variant of the 3320 you have (the 3320-01 and 3320-02 are the common sub-variants), but the belts used on this machine are in the 3L or 4L section range. Confirm the size from the old belt’s markings or the machine’s manual before ordering.

Straight answer: the SKIL 3320’s belt is a specific V-belt size. The most reliable way to order it is to read the size marking molded into the old belt’s inner surface. If the old belt is gone, measure the pulley center-to-center distance and use an FHP belt sizing chart to calculate the correct circumference. Alternatively, find the 3320 variant-specific part number from SKIL’s parts documentation.

Finding the belt size

Three methods, in order of reliability:

1. Read the old belt: The correct size is molded into the rubber on most V-belts. A marking like “3L310” means a 3L section (3/8-inch top width) with 31.0-inch outside circumference. Write it down and order that size.

2. Check the manual: SKIL’s manual for the 3320 (available as a PDF on ManualsLib and SKIL’s website for archived models) lists the belt part number. Cross-reference to a standard V-belt size using the part number.

3. Measure and calculate: With the old belt off, measure the center-to-center distance between the motor shaft and spindle shaft. Use an FHP belt sizing chart to calculate the outside circumference for a belt that fits those centers with correct tension. This method works but adds calculation steps.

Belt section matters as much as length

FHP belts come in different sections (widths and profiles). The 3L section (3/8-inch top width) and 4L section (1/2-inch top width) are common on benchtop drill presses. A belt of the correct circumference but wrong section will not seat properly in the pulley grooves and will slip, heat up, and fail quickly. Match both the length (circumference) and the section.

Ordering and fitting

FHP belts in the common sizes are available from industrial belt suppliers, bearing-and-drive shops, and online. They are not always stocked at home centers, so plan to order rather than walk in. When installing, adjust the motor bracket to achieve proper belt tension: the belt should deflect about 1/2 inch under firm thumb pressure at the mid-span. Over-tightening stresses the spindle bearings; under-tightening causes slipping.

While you have the belt off, inspect the pulleys for glazing (shiny belt contact surface), cracks, or worn step edges. A glazed pulley transfers to glazing and slipping in the new belt. Clean glazed pulley surfaces with light sandpaper before installing a new belt.

The honest flaws

Two honest points. First, the SKIL 3320 is discontinued, so the OEM belt part number may no longer be stocked, making dimensional matching by the old belt or measurement the reliable path. Second, the 3320-01 and 3320-02 sub-variants may use slightly different belt sizes; if you have both variants’ part numbers, confirm which one matches your machine’s specific variant label. Neither is a serious obstacle, just advance awareness that prevents a wrong-size order.

Who should replace the belt themselves, and who should call a service shop

Replace the belt yourself if you can read the old belt’s markings or access the manual’s part number, and you are comfortable adjusting motor bracket position for tension. It is a straightforward job that takes about 20 minutes once you have the right belt.

Call a service shop only if the machine has additional issues (noisy quill bearings, wobbling chuck, switch problems) that warrant a broader assessment. Belt replacement alone is solidly DIY territory.

Conclusion: read the old belt, then order

The SKIL 3320 belt is a specific FHP V-belt size that is easy to source once you have the dimensions.

• Read the size marking from the old belt’s inner surface (e.g., 3L310).
• If the old belt is gone, measure center-to-center and use a sizing chart.
• Match both the section (3L, 4L) and the circumference.
• Order from an industrial belt supplier; FHP belts are not always stocked at home centers.

FAQ

What belt does the SKIL 3320 use? A specific FHP V-belt, likely in the 3L or 4L section. The exact size is on the old belt or in the manual. Confirm before ordering.

Where do I find the belt size markings? Molded into the inner surface of the old belt. Look for a marking like “3L310” or “4L” followed by a number.

What does the belt section (3L, 4L) mean? The section defines the width and profile of the V-belt. 3L is 3/8-inch top width; 4L is 1/2-inch top width. The section must match the pulley groove.

Can I buy the belt at a hardware store? FHP belts in specific sizes are not always stocked at home centers. Order from an industrial supply or belt specialist.

How tight should the belt be? Deflect about 1/2 inch under firm thumb pressure at the mid-span of the longest run. Adjust the motor bracket position to achieve this tension.

Are there different variants of the SKIL 3320? Yes: the 3320-01 and 3320-02 are common sub-variants and may use slightly different belt sizes. Confirm which variant you have.

Is the SKIL 3320 still manufactured? No. It has been discontinued in North America, so OEM part numbers may not be stocked. Dimensional matching from the old belt is the most reliable sourcing method.

References

• SKIL, support and manuals archive: https://www.skil.com/support/manuals
• ManualsLib, SKIL 3320 drill press manual: https://www.manualslib.com/brand/skil/drill-press/?p=2
• FHP V-belt sizing and cross-reference guide: https://www.baldor.com/mvc/DownloadCenter/Files/BR1201E