Civil Engineering Reference
In-Depth Information
Figure 1-22
Ordinary lag screw.
Ta ble 1-9
Lag Screws (inches)
Length
Diameter
5
/
16
to
7
/
8
3
3
1
/
2
5
/
16
to 1
4
5
/
16
to 1
4
1
/
2
5
/
16
to 1
5
5
/
16
to 1
5
1
5
/
2
/
16
to 1
6
5
/
16
to 1
6
1
/
2
7
/
16
to 1
7
7
/
16
to 1
7
1
/
2
7
/
16
to 1
8
7
/
16
to 1
9
7
/
16
to 1
10
1
/
2
to 1
1
/
2
to 1
11
1
/
2
to 1
12
blacksmith, made bolts by the forging process. The first machine
used for this purpose was a device known as a
heading block
, which
was operated by a foot treadle and a connecting lever. The connect-
ing lever held the blank while it was being driven down into the
impression in the heading block by a hammer. The square iron from
which the bolt was made was first rounded so that it could get into
the block.
At first, Rugg only made bolts to order, and charged at the rate
of 16 cents apiece. This industry developed quite slowly until 1839
when Rugg went into partnership with Martin Barnes. Together they
built the first exclusive bolt-and-nut factory in the United States.
Bolts were first manufactured in England in 1838 by Thomas
Oliver of Darlston, Staffordshire. His machine was built on a
Search WWH ::
Custom Search