Holding

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Holding Devices

Session 11

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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

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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

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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

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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

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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

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Types of Drill Chucks

• Keyless • Chuck loosened or

tightened byhand without key

• Precision keyless• Holds smaller drills

accurately

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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

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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

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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

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Drill Drifts

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Drill Drifts

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Drill Drift

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Drill Drift

Rounded edge up

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Work-Holding Devices

• Angle vise• Angular adjustment on base to allow

operator to drill holes at an angle without tilting table

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Work-Holding Devices

• Drill Press Vise• Used to hold round, square or odd-shaped

rectangular pieces• Clamp vise to table for stability

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Work-Holding Devices

• Drill Press Vise

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Work-Holding Devices

• Drill Press Vise

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Work-Holding Devices

• Drill Press Vise

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Work-Holding Devices

• Drill Press Vise

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Work-Holding Devices

• V-blocks• Made of cast iron or

hardened steel• Used in pairs to

support round work for drilling

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Work-Holding Devices

• Step blocks• Used to provide

support for outer end of strap clamps

• Various sizes and steps

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Work-Holding Devices

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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

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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

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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

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Work-Holding Devices

Finger clamp

U-clamp

Straight clamp

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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

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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