Handrail bolt joint
Also called: handrail bolt, joint bolt
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A handrail bolt, also known as a handrail screw, is a double-ended screw fitted with a nut at each end, used to draw two adjoining pieces of timber together and hold a joint closed. Ellis (1908) described it as "a double-ended screw with a pair of nuts used in the joints of handrails".
Sash and mitre joints
In sash frame joinery, the joint where a sash's stile, the vertical side member of the frame, meets the head is cut on the radial, so the joint face lies along a line running to the centre of the curve rather than straight across the timber, and is fixed with a handrail bolt. A cross tongue, a thin strip of wood set into matching grooves cut in both faces to keep them aligned, is fitted on the rebate side, the side with a stepped recess cut along its edge. Ellis (1908) put it this way: "The joint between the stile and head of the sash is made radial and fixed with a handrail bolt, a cross tongue being inserted on the rebate side." The mitred joints at the corners of the sill are cut and fixed the same way, with a cross tongue and a handrail bolt. Hayward (1950) held that mitred joints under heavy stress hold up better when a handrail bolt is used to join them.
In curved handrailing
In handrailing, a butt joint at the far end of a curved section normally falls one handrail-bolt-length past the springing, the point where the rail begins to curve up from a level run. Brett (2005) described the joint where a curved rail meets a sash stile as fixed with a handrail bolt and dowels, sitting just past the springing to leave room to form a shoulder, the flat step cut where the joint's projecting part meets the face of the piece it butts against.
Fitting the bolt
A handrail bolt should be centred in the section and run perpendicular to the joint line, that is, at right angles across it. Before it goes into the joint, it is painted with red lead.