src=/bin/counter.pl?h=1 width=1 height=1>
IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.
5. Types of Iron Ties.
One end is flattened and pierced for nailing and stapling (Fig.5.20) while
the other is formed into a rod with a threaded terminal (Fig.5.21). This end
is passed through a timber and the nut tightened against a washer to close
and secure the joint. A draw-tie could have a forelock key (Fig.5.22) but
the range of adjustment is very limited so it is likely that this type is
used to arrest movement rather than reverse it. (forelock-tie).
A threaded draw-tie from the Stable at Cressing Temple. One of a series of
four, the others are still in-situ. The arm is tapered and nibbed for a staple
and the square punched holes are deliberately offset to prevent the nails
splitting the grain of the timber. Early to mid 19th century.
Close up of the threaded end of a draw-tie. This is a typical profile and
appears to be swaged rather that die-cut. Of good quality wrought iron, there
is little corrosion.
A stapled draw-tie with a forelock key. The inset shows the forelock key.
This unusual tie, found in the Wheat Barn at Cressing Temple is most likely
to date to the early 1500's when a great sequence of works was carried out
on the barn.
5.10 Forelock Bolts.
These are metal pins with a widened head and plain shank. The terminal is
pierced and a rectangular slot filed in it. The bolt is passed through two
or more sections of timber and made tight by driving in a triangular key.
Usually a metal washer is used as a bearing plate and hide washers to act
as spring washers to maintain the tension (Fig.5.23). The key is then bent
over so it cannot be removed. In large bolts the washer is replaced by a bespoke
flange that is pieced to take nails to prevent it pulling out (Fig.5.24).
Forelock bolts have round, mushroom heads (Fig. 5.25) and are principally
used in repair plates, sometimes called clamps (Fig. 5.26) and to prevent
jowled posts from splitting out (Fig. 5.27).
A forelock bolt on a wall post in the Barley Barn at Cressing Temple. The
triangular forelock passes through a slot pierced in the tip of the shank.
A thick metal washer is kept under tension with a hide washer.
This large forelock bolt has a shank diameter of nearly an inch. The nailed
on flange takes place of a washer and helps to spread the considerable load
preventing the bolt from pulling through.
The round, mushroom head of the forelock bolt pictured in Fig. 5.24. This
round head always distinguishes forelocks from threaded bolts which require
square heads so that they may be turned with a spanner.
Oak Cottage, Great Yeldham. The mushroom heads of two forelocks bolt passing
through a clamp on the back wall. In this case it was possible to see the
actual forelock outside. Compare this with the T-pin used on the front wall
pictured below in Fig. 5.28.
A forelock bolt in the jowl of a split wall post in the Barley Barn at Cressing
Temple. The hide washers are clearly visible and most of the key has corroded
away. The later addition of the L-tie above has relieved the stress and made
the forelock redundant.
Split cotters used in place of bolts. The free ends are splayed out to secure
the joint. In use at the same time as forelocks and so are likely to be a
local variant. An unusual fitment, it is difficult to ascertain which way
round they were used or how they are fastened (Fig. 5.28).
The head of a T-pin securing a clamp on the front wall of Oak Cottage, Great
Yeldham, Essex. Because the other end is not visible it is not possible to
tell if this is the head or the terminal of the pin. In domestic buildings
the bolts normally have their heads on the outside whereas in farm buildings
the opposite is true.
5.13 Tie rods and tie bars.