Mechanical Engineering Drawing MENG 204 Fasteners & shafts Summer Semester 2015 By: Dr. Ghassan Mousa

Thread standards & definition Threaded fasteners Used to non-permanently join one or more objects together. Thread standards & definition d: major diameter p: pitch l: lead Multiple threads Die for external threading. https://www.youtube.com/watch?v=gVcwjjBAT4Q Tab for internal threading Fig. 8.1 Terminology of screw threads http://www.walter-tools.com/en-gb/tools/standard_products/threading/overview/hss_tap/eco_ht/Pages/default.aspx http://www.gizmology.net/nutsbolts.htm

Types Three types of threaded fastener. (a) Bolt and nut; (c) Cap screw; (c) stud.

Metric thread Thread angle is 60˚ M8 × 1.25 Imperial thread 3/8 – 24 UNF Table 8-1 Geometrical data for Standard Bolts (SI)

Power screw Trapezoidal thread Thread angle is 30˚ Tr 36 X 10 Buttress Thread S 40 X 7 Loading Direction

Strength Bolts in axial loading fail at the: Fillet under the head. Thread runout. 1st thread engaged in the nut. Table 8-11 Material properties of steel bolts

Setscrew washer Nuts Slotted nut jam nut Prevailing torque locknut

Design (Configuration)

Design (Head Style)

Design (Drive Type)

Thread dimension Threaded Fasteners Preferred Sizes (Length): 2, 3, 4, 5, 6, 8, 10 12, 16, 20, 25, 30 35-60, 65, 70, 80 90-140, 150, 160, 180, 200

Shafts Stepped shaft Used to transmit power (torque). The shorter the better. Load carrying components should be placed near the bearing. Means of transmitting power through: Gears Belts Chains Torque is transmitted by using keys Axial force is supported by using Pins Stepped shaft

Retaining rings E ring External ring

Keys Woodruff key Tapered key Gib head tapered key

Pins Spring pin Hairpin cotter Dowel pin Cotter pin Tapered pin