Owner’s manual
How to attach a drill bit to a Craftsman drill?
To attach a drill bit on your Craftsman 315271490 3/8-inch professional electric drill, unplug the drill first, open the chuck jaws slightly wider than the bit, insert the bit fully into the jaws, then hand-tighten the chuck by holding the collar and turning the chuck body to the LOCK direction (no wrench).
- Unplug the drill before installing or removing bits.
- Rotate the chuck to open the jaws until the opening is slightly larger than the bit.
- Insert the drill bit straight in, the full length of the jaws.
- Hold the chuck collar with one hand.
- Rotate the chuck body with your other hand toward LOCK until the bit is tight.
- Tug the bit lightly to confirm it is seated and secure.
- Tightening the chuck with the bit only partially inserted
- Clamping down on the bit’s flutes instead of the smooth shank (when applicable)
- Leaving dust or rust in the chuck jaws
- Using a wrench or pliers on the chuck (this drill is designed for hand tightening)
| Check | Correct | Incorrect |
|---|---|---|
| Bit depth in jaws | Inserted fully into jaws | Barely started in jaws |
| Bit alignment | Straight, centered | Tilted or off-center |
| Tightening method | Hand-tighten collar/body | Wrench or pliers |
A properly seated bit reduces chuck damage, prevents the bit from being thrown, and helps you drill cleaner holes with less vibration. It also improves control when the drill binds or breaks through material.
For the chuck diagram (chuck body, chuck collar) and the LOCK/UNLOCK directions, use the 315271490 owner's manual.
Last updated: February 2026
What are the parts of a drill?
On the Craftsman 315271490 3/8 in. professional electric drill, the main user-facing parts include the keyless chuck (to hold the bit), the switch trigger (to run the drill), and the forward-reverse lever (to change rotation direction). For the full diagram and names, use the owner's manual.
These are the components you typically touch or adjust during drilling:
- Keyless chuck and chuck jaws: hand-tighten to clamp the drill bit
- Switch trigger: starts the drill; more trigger pressure increases speed
- Lock-on button: keeps the drill running for extended drilling
- Forward-reverse lever: selects clockwise or counterclockwise rotation (change direction only when stopped)
- Level: helps keep the bit level in horizontal or vertical drilling
- Belt clip: molded into the motor housing for carrying
| Part | What it does | Why you care |
|---|---|---|
| Keyless chuck | Holds the bit from 1/16 in. to 3/8 in. | Prevents bit slip and wobble |
| Variable-speed trigger | Controls speed and torque by trigger pressure | Helps avoid stripping screws and improves control |
| Forward-reverse lever | Changes rotation direction | Needed for backing out screws or freeing a stuck bit |
| Lock-on button | Runs continuously without holding the trigger | Reduces hand fatigue on long holes |
From the Craftsman 315271490 manual, these specs guide what accessories fit and how the drill performs:
- Chuck capacity: 1/16 in. to 3/8 in.
- No-load speed: 0 to 2500 RPM
- Electrical rating: 120V, 60 Hz, AC only
- Input: 4.0 amps
- Net weight: 3.875 lb
Knowing the correct part names helps you troubleshoot issues (for example, a slipping bit points to the chuck or jaws) and helps you identify the right repair parts and accessories for safe, reliable drilling.
Last updated: February 2026
How to get the drill bit out of a Craftsman drill?
To remove a drill bit from your Craftsman 315271490 3/8 inch professional electric drill, unplug the drill first, then loosen the chuck jaws by holding the chuck collar and rotating the chuck body toward UNLOCK until the bit slides out. Do not use a wrench.
- Unplug the drill from the power supply before touching the chuck.
- Hold the chuck collar (the ring behind the jaws) with one hand.
- Rotate the chuck body with your other hand toward the arrow marked UNLOCK.
- Open the jaws enough that the bit is free.
- Pull the bit straight out of the chuck jaws.
- If the bit wants to drop, tip the drill slightly upward while loosening.
- Keep the drill unplugged and open the jaws wider, then try again.
- Wiggle the bit gently while continuing to rotate the chuck body toward UNLOCK.
- Check for debris or rust in the jaws; wipe the jaws and bit shank clean before reinstalling.
- If the chuck will not turn by hand, the chuck may be damaged and needs service.
| What you do | What moves | Result |
|---|---|---|
| Rotate chuck body toward UNLOCK while holding collar | Jaws open | Bit releases |
| Rotate chuck body toward LOCK while holding collar | Jaws close | Bit tightens |
| Use a wrench | None (not recommended) | Can damage chuck |
Unplugging prevents accidental starting while your fingers are near the chuck jaws. Loosening the chuck the correct direction also protects the chuck mechanism and helps prevent the bit from binding or being thrown.
For the exact chuck parts and safety notes for this model, follow the procedure in the 315271490 owner's manual.
Last updated: February 2026