 | Fundamentals of Fitting - Course: Techniques of Fitting and Assembling Component Parts to Produce Simple Units. Instruction Examples for Practical Vocational Training |
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Instruction Example 31.3. Locking handle for Three-jaw Chuck Wrench
Practising of the fitting of bores in preparing pinned joints by manual reaming.
Material
Figure
- square bolt from the 2. instruction example
- round stock made of steel (380 MPa)
diameter: 32 mm
length: 36 mm
- cylindrical pin
Æ 10 m 6
length: 80 mm
- cylindrical pin
Æ 6 m 6
length: 36 mm
Tools
Marking-out tool, centre punch, hammer, aluminium hammer, drills Æ 15.8 mm, Æ 9.8 mm, Æ 5.8 mm, countersink of 90°, cylindrical hand reamers Æ 16 E 8, Æ 10 H 8, Æ 6 H 8
Measuring and testing means
Steel rule, vernier caliper, centre square
Auxiliary accessories
Vice, machine vice with Vee-jaws, boring emulsion, cutting oil, tap wrench, machine grease
Necessary previous knowledge
Manual working of materials - measuring, testing, marking, boring, countersinking, reaming
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Sequence of operations |
Comments |
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1. Prepare the workplace, make the working material available | |
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2. Drill the central bore hole for the insertion of the square bolt into the head by drilling up to Æ 15.8 mm and spot-facing on both sides to 16.2 mm |
- Clamp the workpiece so that it cannot twist |
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3. Ream the bore with the hand reamer to Æ 16 E 8 |
- Stage (1) |
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4. Insert the square bolt by hand |
- Clearance fit; mating parts move easily into each other |
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5. Make the precision bore for the lock Æ 10 m 6 with the hand reamer Æ 10 H 8 |
- Stage (2) boring, countersinking, reaming |
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6. Insert the slightly greased lock with the aluminium hammer |
- Interference fit; fitting together takes greater efforts |
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7. Finish the precision bore for the fitting pin Æ 6 m 6 with the hand reamer Æ 6 H 8 |
- Stage (3) bore a hole which is stepped to the lock by 90° |
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8. Drive in the slightly greased fitting pin with the aluminium hammer |
- Interference fit |
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9. Check the interference fits for tightness (mating parts must be snugly fitting) | |
Figure
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