Lignum Vitae North America participates in establishing a ‘New World Record’ for testing the tension in a mortise and tenon joint!

LVNALLC participates in establishing a new world record for testing the tension in a mortise and tenon joint beating the 25 year standing record by 400%. Bob Shortridge, President of Lignum Vitae North America LLC., provided IPE and Lignum Vitae timbers to be tested for a previously unknown joinery technique he developed using a tapered key into a plowed rabbet to achieve an extraordinary tension of 80,935 lbs. This was after participating in a contest held by the Timber Framers Guild of North America last fall when Shortridge entered the unconventional joinery.

The joint he designed not only defeated the 20 ton hydraulic tester but shattered the old record of 16,900 lbs. of vertical pull with his keyed rabbited slot when the new joint held to the astounding number of 80,935 lbs. After defeating the Guilds tester last fall Grigg Mullen professor of Engineering at VMI Virginia Military Institute offered to do another test on their 200,000 lbs test puller with Bobs son Caleb assisting as a Civil engineer student at VMI. Four new joints were made by joining a total of 80 cross sections made of two 4” x 10” timbers using traditional timber joinery of IPE and lignum vitae pegs with the twist of adding tapered rabbeted keys, the previous record of 16,900lbs. was made from 384 cross section inches with two 12” x 16” timbers. Put another way the record was beat 4x using only 25% of the material.

Currently the design specifications for this size joint will allow about 4-5,000lbs of tension. This new record using Lignum-Vitae pegs shatters the modern engineering standards and secures Lignum-Vitae as an extraordinary material. This material has a working load of 12,800 Pounds Per Square Inch. Originally specified by Thomas Edison in Hydro Power plants this testing will be part of the process to give newly educated engineers formal charts to refer to its extraordinary performance.

It is Shortridge’s hope that enough was learned from this joint to give further study ultimately giving engineers and practitioners a stronger and tougher joint when heavier loading is needed in a smaller cross section.

Bob was President of Dreaming creek Timber Frame Homes for 30 years handing the reigns to his son Bobby Jr. before retiring to start Lignum Vitae North America LLC.

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