Steel Beam Trammels C251 Steel Beam Trammels and Att achments 10-1/2 – 20"/260 - 500MM BEAMS A rigid, well-designed trammel for layout, scribing, and measuring distances and circles.The top of the beam is flattened so that when the trams are clamped in position, they will not turn from pressure on the points. The trams are held in place by spring friction, which prevents them from sliding when the nuts are loosened for setting. One tram has a fine-adjusting screw for the points. Each tram has a knurled swivel grip at the top that turns freely, making it very convenient to swing the tool when scribing circles. The 3" (75mm) points may be adjusted for length in the spring chucks and can be easily replaced with caliper legs or other attachments listed.The ball points with 3" (75mm) holder permit working from holes up to 1-1/2" (38mm) in diameter.A pair of 3" (75mm) caliper points is included with each trammel. • Ideal for draftsmen, engineers, metal-workers for layout work, scribing and measuring • Furnished with rigid steel beam – 10-1/2" (263mm), 14-1/2" (360mm) or 20" (500mm) sizes • Bright chrome finish for longer life, resistance to corrosion • Highly versatile – handy attachments available to extend range and measure C251A J H D E C251 Steel Beam Trammels Cat. No. EDP Max. Dividing Range Max. Circle Scribing Diameter Range Beam Size in mm in mm in mm C251A 51205 9 225 18 450 10-1/2 263 C251B 51207 13-1/2 338 26 650 14-1/2 363 C251C 51209 18 450 36 900 20 500 C251 Trammel Individual Attachments Only Photo Key Cat. No. EDP Description D C251D 51211 Coupling, with extra 20" (600mm) beam (when used with C251C will scribe circle 72" [1800mm] diameter) E C251E 51212 Ball points and holder H C251H 51214 Steel point and socket (one) (has .076" [1.9mm] hole diameter to hold leads) J 251J 51203 Needle point (chrome not available) (one) 317 C alipers , D ividers and T rammels