Term
List the recommended speeds of each operation in compared to regular drilling:
-Reaming: Spindle Speed/Feed
-Counter-Boring: Spindle Speed
-Counter-Sinking: Spindle Speed
-Spotfacing: Spindle Speed |
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Definition
-Reaming should be done at 1/2 - 2/3rds the spindle speeds and 2 or 3 times the feed.
-Counter-Boring should be done at about 1/4th the speed of drilling and constant pressure should be applied.
-Counter-Sinking should be done at about 1/4th the spindle speed and should be firmly fed into the material.
-Spotfacing should be done at about 1/4 the speed of drilling. |
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Term
| What is the best way to hold round stock for drilling? |
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Definition
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Term
| What is the point angle of a general purpose drill? A drill for soft materials? A drill for tough materials? |
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Definition
| The included angle of a general purpose drill should be 118 degrees. A drill for soft materials should be between 60 and 90 degrees and hard between 135 and 150 degrees. |
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Term
| What is the clearance angle required for general purpose drilling? What would happen without this clearance? |
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Definition
| The angle required is 8-12 degrees. Without the clearance or with too little the drill can not be fed into the work properly. With too much the cutting edges will not have enough support and will chip/wear easily. |
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Term
| What is the purpose of an angle plate when drilling? |
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Definition
| It is used to bolt odd shaped work to it for drilling. It is also useful for drilling at right angles to a surface. |
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Term
| What are the 3 parts of a drill? |
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Definition
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Term
| What gives a sensitive drill press its name? |
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Definition
| A sensitive drill press has no power feed, it must be fed manually by hand. This allows the operator to sense the cutting forces, thus its name. |
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Term
| What is the purpose of a quill on a drill press? |
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Definition
| Its purpose is to hold the spindle and provide the vertical movement of the drilling set up. |
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Term
| Sensitive drill presses are typically for ____ holes and _____ work. |
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Definition
| Sensitive drill presses are typically for small holes and precise work. |
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Term
| How is coolant usually applied on a sensitive drill press? |
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Definition
| Coolant is typically applied by the operator with a squirt can or other method. |
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Term
| What is the main 2 differences between a sensitive drill press and upright drilling machine? |
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Definition
| An upright drilling machine will be larger and it has power feed. |
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Term
| The base of a upright drilling machine will typically have coolant stored... |
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Definition
| The base of a upright drilling machine will typically have coolant stored in the base with a pump to apply it. |
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Term
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Definition
| A gang drill is for mass production, it has multiple independent drilling heads with one single table. Operations can be performed quickly by doing one operation with the first drill than moving it down the table to the next. (i.e. you could drill, countersink and tap all in one quick set up) |
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Term
| What is the purpose of a multi-spindle attachment? |
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Definition
| A multi-spindle attachment is for drilling multiple holes at once. It is made for mass production. |
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Term
| What drilling machine is best suited for very large workpieces? |
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Definition
| A radial arm drilling machine. |
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Term
| How can be the spindle of the radial drill press be positioned? |
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Definition
| It can be positioned anywhere within a certain radius of the column. The drilling head slides along the radial arm horizontally and can be moved vertically and around the column. |
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Term
| What type of drilling machine automatically indexes to the next cutting tool after performing one operation? |
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Definition
| The turret drilling machines automatically index to the next tool on the upstroke after performing an operation. |
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Term
| How are sensitive and upright drill presses sized? |
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Definition
| They are sized by the distance from column to tool and by the largest diameter of work piece that can be centred under the tool. |
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Term
| Drilling pilot holes are necessary for holes over ___ in diameter. |
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Definition
| Drilling pilot holes are necessary for holes over 3/4" in diameter. |
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Term
| What kind of drills are used for deep hole drilling? |
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Definition
| Either a deep hole, gun or ejector drill are ideal for drilling holes that are very deep compared to their diameter. |
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Term
| What are the 7 steps for drilling work held in a vice? |
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Definition
1) Mark the hole with a centre punch mark at least as large as the chisel edge of the drill.
2) Clean the vice and table and ensure clearance between the workpiece and the vise under the hole.
3) Place the work int he vise and tighten it. Use a soft faced hammer to drive the workpiece flat.
4)Position the workpiece under the centre of the spindle. Turn it in reverse and carefully lower the drill into the punch mark. This will draw the workpiece into alignment or make it clear where you need to push the work to align it yourself.
5) Raise the drill, clamp the vise in place being careful not to move it.
6) Set the spindle speed and feed rate and apply coolant where the drill enters the work.
7) Drill the Hole. |
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Term
| The larger the drill the _____ the feed rate and the _____ the spindle speed. |
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Definition
| The larger the drill the higher the feed rate and the lower the spindle speed. |
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Term
| What is the best way to drill two parts that are meant to have holes that align? |
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Definition
| The best method is to clamp the two pieces together and drill them as one. This way the holes can't be misaligned. If one of the holes has already been driled you can use a transfer punch, a transfer screw or the twist drill method. |
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Term
| What is required when drilling round work? |
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Definition
| Before you can drill round work you need a deep centre punch mark that is centred exactly above the axis of the shaft. Position the centre punch pmark using a square and scale. |
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Term
| Before machine reaming how much smaller of a hole should you drill? |
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Definition
| For reamed holes up to 1/2" the drilled hole should be 1/64" smaller than nominal size of the reamer. Reamed holes larger than 1/2" drill a hole 1/32" smaller than the nominal size of the reamer. |
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Term
| What is the purpose of a depth stop? |
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Definition
| A depth stop is to stop your drills feed(either powered or manual) once it reaches a certain depth. Used for drilling a specific depth accurately. |
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Term
| What is the purpose of counter-boring? |
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Definition
| Counter-boring is the process of enlarging the top of an existing hole to accept the head of a bolt or screw. |
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Term
| What is the purpose of Counter-sinking? |
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Definition
| The purpose of a counter-sink is to accept the head of a flathead screw (Typically a 82 degree included angle) |
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Term
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Definition
| Boring is the process of enlarging an existing hole using a single point tool. It allows a hole to be bored to any precise, perfectly round size required that is within range of the boring bar. |
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Term
| What is the purpose of spotfacing? |
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Definition
| Spotfacing is the process of squaring the surface of a workpiece to a drilled hole. |
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Term
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Definition
| Hole sawing is the process of cutting a large hole in thin stock using a pilot drill and a round saw. The drill acts as a guide for the saw preventing it from wandering. |
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Term
| What are the two main types of drill chucks? How are the drills tightened in them? Which one holds better? |
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Definition
| Key Type and Keyless. A key type is tightened with a key turned in the hole of the chuck. A keyless is tightened by turning the collar. The key chuck has more holding power. |
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Term
| How are drill chucks sized? |
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Definition
| They are sized according to the largest drill they will hold. |
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Term
| What is the difference between a drill socket and a drill sleeve? |
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Definition
| A drill socket decreases the taper diameter taking the tool from larger to smaller. A drill sleeve increases the taper diameter taking the tool from smaller to larger. |
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Term
| What tool is used to separate drill sleeves and sockets from the tapers joined with them? |
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Definition
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Term
| When do Quick-Change tool holders become quite useful? |
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Definition
| When a sequence of operations must be performed time and time again. It is easy to interchange the sockets with different drills attached to each. |
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Term
| What is the most convenient and versatile work holding device? |
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Definition
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Term
| When drilling long pieces of work where should you place parallels? |
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Definition
| Parallels should be place on each end as well as parallels close to each side of the hole to prevent the work from flexing and drilling an inaccurate hole. |
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Term
| What must strap clamps be used with? Where should the bolt be positioned? |
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Definition
| Strap clamps must be used with parallels and step blocks or spacer blocks. Position the t-bolt as close to the work as possible. |
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Term
| What is the purpose of a margin on a drill? |
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Definition
| The margin of a drill gives it the outside diameter, it is slightly larger than the body and prevents the drill from rubbing while drilling. |
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Term
| What are the two types of drill shanks? |
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Definition
| Straight and Tapered(morse). The tapered shank is usually used on drills larger than 1/2". |
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Term
| Does the web becomes thicker or thinner as it goes from the chisel edge to the margin? |
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Definition
| The web becomes thicker as it goes from the chisel edge to the margin. |
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Term
| Where does the cutting action of a drill take a place? |
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Definition
| The cutting action takes place on the point of the drill. |
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Term
| What direction is the helix of most drills? |
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Definition
| The helix of most drills have a right handed helix. |
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Term
| What is the purpose of high helix drills? |
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Definition
| High helix drills are made for drilling deep holes in soft materials. Soft metals would typically jam a normal drill. |
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Term
| What is an oil hole drill? |
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Definition
| Oil hole drills have one or two small holes that run the length of the drill and exit just behind the cutting edges. Cutting oil, coolant or ait is forced through these holes to keep the cutting edges cool and helps flush chips back out of the hole. |
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Term
| What is the purpose of core drills? |
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Definition
| Core drills are used to enlarge existing holes. They cannot start a hole but when used to enlarge one they provide a very good finish and can be run at high feed rates. |
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Term
| What is the purpose of core drills? |
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Definition
| Core drills are used to enlarge existing holes. They cannot start a hole but when used to enlarge one they provide a very good finish and can be run at high feed rates. |
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Term
| What kind of drill has a removable blade? |
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Definition
| A gun drill has a removable carbide insert that can be changed to increase the diameter of the hole it will drill. |
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Term
| What are carbide indexable insert drills(U-drills) typically used for? |
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Definition
| They are often used in CNC machines as they require high horsepower and a very rigid set up. They can drill at very fast rates. |
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Term
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Definition
| Step drills are used to drill and countersink or bore in one operation. |
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Term
| How should centre drilling be done? |
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Definition
| Centre drilling should be 'peck-drilled' and lubrication is strongly recommended to avoid breaking the cutting point. Typically you should drill 2/3 up the tapered portion of the drill. |
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Term
| What are the different drill sizing systems? |
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Definition
Fractional
Number #1(largest) - #97(smallest)
Letter A(smallest) - Z(largest)
Metric |
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Term
| What can cause the margin to wear down? |
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Definition
| The margin of a drill can wear down if you are running the drill too fast. |
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