Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. 2. Bar and bed lathes. Wooden bearers — Triangular iron bar lathe. — The iron bar, compared with rectangular iron bearers — Sections of. Iron lathe bearers — Torsion. — Extension of the triangular bar lathe. Various forms of gap and break lathe bearers, used by the engineer.