Drilling Flashcards
Which variable is the most important when determining spindle speed?
Diameter of the drill
Any machined surfaces on a drill press that could rust must be ________________.
Kept clean and oiled
When using a magnetic base drill to drill horizontally, what safety precautions must you take and why?
Be sure the power supply to the drill is secure and that any joints in the electric cord are knotted at the joint. Chain the drill to a secure support. This drill is heavy and can cause serious injury if it drops suddenly.
When installing a taper shank drill into the spindle bore, you must take several precautions. What are they and why?
Make sure that the drill taper and the bore are both clean. Wipe them with a rag. Be careful not to scrape or mark the internal taper of the spindle bore. Any burrs in the taper will throw your drill bit off centre and prevent a tight fit for the drill.
Cutting speed refers to:
Peripheral speed
How fast should a 1/2 inch drill turn when drilling mild steel if the cutting speed (CS) is 90 surface feet per minute?
720 RPM
Small drills require a higher feed per revolution than larger ones.
- True
- False
False
Which abbreviation is used to express the feed rate on a drill press?
IPR - Inches Per Revolution
A drill press spindle has a #2 Morse taper. A twist drill with a #3 Morse taper shank must be mounted in the spindle. How should you secure the drill in the spindle?
- Use a drill sleeve
- Use a drill socket
- Use a Jacob’s keyless drill socket
Use a drill socket.
To remove a tapered shank twist drill from the drill press spindle, use a:
Drill Drift
Drill chucks may be mounted in the drill press spindle or a tapered shank by means of a:
Taper of Thread
V-blocks are used mostly on the drill press for?
For holding round stock for cross drilling
To clamp a workpiece correctly with a straight clamp, you must?
Place the bolt close to the workpiece, and the clamp should be level or slightly raised on the tail end.
When using a sensitive drill press, what should you do as the drill breaks through the workpiece?
Ease up on the pressure
The recommended drill size for reaming a 3/8 inch hole on a drill press is:
23/64th
Leaving 1/64th for the reamer.
The included point angle of a countersunk hole for most flathead screws is:
82 degrees
Which type of machine tap will push the chip out ahead of the tap?
Spiral point (gun) tap
The lip relief (clearance) angle on a drill should be:
8 to 12°
A general-purpose drill bit for drilling most metals has an included point angle of:
118°
Carbide drills may be operated at a cutting speed how many times faster than high-speed steel drills?
Three
A drill that is ground with lips of unequal length will drill a hole which is:
Oversized
The hand drill is quicker and more versatile than any drill press for:
For drilling small non-vertical holes
Electric hand drills are limited by :
The amount of feed pressure (and rpm) that can be applied to large-diameter drills
A magnetic-base drill offers:
More control of the feed pressure, torque and drilling angle than are possible with a large hand drill
The most common sizes of three-jaw chucks found on a magnetic-base drill are:
1/2 inch and 3/4 inch only.
Name 5 types of drilling machines:
- Sensitive Drill Press
- Upright Drill Press
- Hand Drills
- Magnetic Base Drills
- Radial Drilling Machines
Name the three parts to a twist drill bit:
- Point
- Body
- Shank
Name the two types of shanks commonly found on a twist drill bit:
- Taper Shank
- Straight Shank
What is the TPF of a Morse taper?
5/8 inch taper per foot
For Review
- Flute
- Heel
- Lip or cutting edge
- Web
- Chisel Edge
- Lip Clearance
- Margin
- Land
Fractional size drills are available in diameters from 1/16 inch to 4 inches. They increase in size by increments of 1/64 inch, up to a diameter of 1 3/4 inch. Thereafter they increase by increments of 1/32 inch.
For Review
Number size drills range from #97 (0.0059 inch) to #1 (0.228 inch) in diameter. The increment between sizes increases as the drills get larger.
For Review
Letter size drills range from 0.234 inch to 0.413 inch in diameter and are identified by a letter ranging from A (smallest) to Z (largest). The letter range picks up where the number range leaves off.
For Review
Metric size drills range from 0.04 mm to 80 mm in diameter. The increment between sizes increases as the drills get larger.
For Review
What is the general rule for sizing a pilot hole?
Pilot hole should be the same size as the chisel edge.
