By Albert Curutchet and Shiphra Seera

The Nuts and Bolts behind Engineering

SRJC, ENGR45, 2012

HISTORY OF BOLTS Nuts and bolts were invented

in as early as the 1st century,

The Romans used them to bind windows, secure chariots and build machines.

In as early as the 1400’s, Leonard DaVinci and Luc Besson had designs of bolts

The first nuts and bolts had square heads unlike the one used today that are hexagonally shaped.

The first bolts were handmade.

ANOTOMY OF BOLTS AND THREADS

Type of heads

Grip

Thread pitch

Length

Chamfer

Thread length

diameter

TAPPING

The process of running a tap in a blank hole in order to cut threads.

Process

Direction we wanted to go

To check the amount of torque required to pull thread for ½ inch 836 steel.

Then re-tapped with common thread repair kits

Bolts failed and change the process

Then proceeded with grade 8 bolts pulling different amount of threads

Direction we ended up going

We used a torque wrench to measure the amount of force a grade 5 and grade 8 bolt can take before it failed critically.

Analysis of torque on the bolts.

Grade 5 bolt Grade 8 bolt

•Torque value: 67 ft.lb •Torque value: 90 ft.lb

WHEN COMPARED TO THE THEORETICAL RESULTS….

OUR RESULTS WERE MUCH GREATER THAN THE THEORITCAL VALUES!!?!!

GRADE 5 BOLT

3/8 inch bolt tightening torque is 31ft/lb

GRADE 8 BOLT

3/8 inch has tightening torque of 44ft/lb

THEORITCAL VALUES

•We tested effect of pressure on grade 8 bolt.

•The bolt was compressed at 7000psi to get to this point (as shown in picture)

•Tried to de-thread a nut.

WE ALSO!!!

HOW BOLTS ARE MADE

SOURCES

"Bolt Torque Chart." Anchor Bolts and Construction Fasteners. N.p., n.d. Web. 04 Dec. 2012.

"Components Diagram." Racing Bolts Components. N.p., n.d. Web.

"History of Nuts and Bolts." History of Nuts and Bolts. N.p., n.d. Web. 04 Dec. 2012.

YouTube. YouTube, n.d. Web. 04 Dec. 2012.

"Nut Bolt Fastener Bearings." Rupali Enterprises. N.p., n.d. Web. 04 Sept. 2012.