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Holding Devices Session 11
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
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
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
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
Types of Drill Chucks Key-type Most common Three jaws move simultaneously when outer sleeve turned Tighten with key Different size keys for different size chucks
Types of Drill Chucks Keyless  Chuck loosened or tightened by hand without key Precision keyless Holds smaller drills accurately
Types of Drill Chucks Jacobs impact keyless chuck Hold small or large drills using Rubber-Flex collets Gripped or released quickly and easily by means of built-in impact device in chuck
Drill Sleeves and Sockets Drill Sleeves Used to adapt drill shank to machine spindle if taper on tool is smaller 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
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
Drill Drifts
Drill Drifts
Drill Drift
Drill Drift Rounded edge up
Work-Holding Devices Angle vise Angular adjustment on base to allow operator to drill holes at an angle without tilting table
Work-Holding Devices Drill Press Vise Used to hold round, square or odd-shaped rectangular pieces Clamp vise to table for stability
Work-Holding Devices Drill Press Vise
Work-Holding Devices Drill Press Vise
Work-Holding Devices Drill Press Vise
Work-Holding Devices Drill Press Vise
Work-Holding Devices V-blocks Made of cast iron or hardened steel Used in pairs to support round work for drilling
Work-Holding Devices Step blocks Used to provide support for outer end of strap clamps  Various sizes and steps
Work-Holding Devices
Work-Holding Devices Angle plate L-shaped piece of cast iron or hardened steel machined to accurate 90 º May be bolted or clamped to table Variety of sizes
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
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 and bolted to table by T-bolt that fits into table T-slot
Work-Holding Devices Finger clamp U-clamp Straight clamp
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
Clamping Hints Always place bolt close to workpiece Have packing block slightly higher than work surface being clamped Place metal shim between clamp and workpiece Use sub-base or liner under rough casting Shim parts that do not lie flat to prevent rocking