HISTORIC IRONWORK REPAIRS IN TIMBER-FRAMED BUILDINGS.

Chapter 5.

5. Types of Iron Ties. 4/6.

5.9 Draw-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).

Fig.5.20. 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.

Fig.5.21. 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.

Fig. 5.22. 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).

Fig. 5.23. 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.

Fig. 5.24. 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.

Fig. 5.25. 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.

Fig. 5.26. 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.

Fig. 5.27. 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.

5.11 T-pins.
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).

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.

5.12 Pin-ties, 5.13 Tie rods and tie bars.