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1
Holding Devices
Session 11
2
Versatility of the Drill Press• Greatly increased by various
accessories
• Two categories• Tool-holding devices
• Used to hold or drive cutting tool
• Work-holding devices• Used to clamp or hold workpiece
3
Tool-Holding Devices
• Drill press spindle provides means of holding and driving cutting tool
• End may be tapered or threaded for mounting drill chuck
• Most common• Drill chucks• Drill sleeves• Drill sockets
4
Drill Chucks
• Most common devices used for holding straight-shank cutting tools
• Most contain three jaws that move simultaneously when outer sleeve turned• Hold straight shank of cutting tool
securely
• Two common types• Key • Keyless
5
Chucks
• Hold straight-shank drills
• Mounted on drill press spindle• Taper
• Threads
• Held in spindle by self-holding taper in larger machines
• Four types of drill chucks
6
Types of Drill Chucks
• Key-type• Most common• Three jaws move
simultaneouslywhen outer sleeve turned
• Tighten with key• Different size keys for
different size chucks
7
Types of Drill Chucks
• Keyless • Chuck loosened or
tightened byhand without key
• Precision keyless• Holds smaller drills
accurately
8
Types of Drill Chucks
• Jacobs impact keyless chuck• Hold small or large drills
using Rubber-Flexcollets
• Gripped or releasedquickly and easily bymeans of built-inimpact device in chuck
9
Drill Sleeves and Sockets
• Drill Sleeves• Used to adapt drill
shank to machinespindle if taper on tool issmaller than taper in spindle
• Drill Socket• Used when hole in spindle of drill press too
small for taper shank of drill• Used often as
extension sockets
10
Drill Drift
• Used to remove tapered-shank drills or accessories from drill press spindle
• Always place rounded edge up so this edge will bear against round slot in spindle
• Use hammer to tap drill drift and loosen tapered drill shank
• Use board or piece of pressed-wood to protect table or vise
11
Drill Drifts
12
Drill Drifts
13
Drill Drift
14
Drill Drift
Rounded edge up
15
Work-Holding Devices
• Angle vise• Angular adjustment on base to allow
operator to drill holes at an angle without tilting table
16
Work-Holding Devices
• Drill Press Vise• Used to hold round, square or odd-shaped
rectangular pieces• Clamp vise to table for stability
17
Work-Holding Devices
• Drill Press Vise
18
Work-Holding Devices
• Drill Press Vise
19
Work-Holding Devices
• Drill Press Vise
20
Work-Holding Devices
• Drill Press Vise
21
Work-Holding Devices
• V-blocks• Made of cast iron or
hardened steel• Used in pairs to
support round work for drilling
22
Work-Holding Devices
• Step blocks• Used to provide
support for outer end of strap clamps
• Various sizes and steps
23
Work-Holding Devices
24
Work-Holding Devices
• Angle plate• L-shaped piece of
cast iron or hardened steel machined to accurate 90º
• May be bolted or clamped to table
• Variety of sizes
25
Work-Holding Devices
• Drill jigs• Used in production for drilling holes in large
number of identical parts• Eliminate need for laying out a hole location
26
Work-Holding Devices
• Clamps or straps• Used to fasten work to table or
angle plate for drilling• Various sizes• Usually supported at
end by step block andbolted to table by T-boltthat fits into table T-slot
27
Work-Holding Devices
Finger clamp
U-clamp
Straight clamp
28
Clamping Stresses
• Don’t want stresses to cause springing or distortion of workpiece
• Clamping pressures should be applied to work, not step block• Step block should
be slightly higher
than work• Bolt close to work
29
Clamping Hints
1. Always place bolt close to workpiece
2. Have packing block slightly higher than work surface being clamped
3. Place metal shim between clamp and workpiece
4. Use sub-base or liner under rough casting
5. Shim parts that do not lie flat to prevent rocking