Dividers: How to Lock Your Legs 

                                                   Part 2: At the Hinge Joint

In Part 1 of this topic we looked at the most common way of locking divider legs in place by means of a traditional wing. In this post we’ll look at the less common technique focusing on locking the legs at or very near the hinge itself. 

A most interesting and early example of locking the joint is pictured below. It was manufactured by the English firm of R. Timmins & Sons, Birmingham and is so marked. The model is shown on a plate from a Timmins Pattern Book, 1800 -1845 showing this design (Tools For The Trades and Crafts, Kenneth D. Roberts, 1976). This tool appears to have been manufactured at the earlier end of the range.

                                                

 

The remaining examples in my collection involve locking the legs at (or slightly above) the joint. These are mainly machinist calipers made from flat stock. The two leaf hinges lend themselves to being squeezed shut.                     

                                                 

Both are L.S. Starrett, Lilja’s 1885 patent, marked

            The larger pair are inside calipers with an interesting fine adjustment mechanism     

 

                           

J. Stevens A&T (marked) outside calipers. No. 56A “Vise Clamp”

    

  

                                                    

McGrath, St. Paul (marked) 

               

Since examples of this locking method are limited, I’ll add two other interesting examples that don’t fall into one of the three categories I’ve outlined. Both appear to be user made and possibly “one offs”, but certainly crafted by a creative mind!   

                                                  

                                                         

Based on the overall design and noting the “ram’s head” thumb screws, these dividers possibly date from the late 1700’s. Unmarked.

 

                                             

      Certainly, a creative design. One problem may be that the legs don’t lock very well. Marked “H” on one leg and one brass arm. This is often done to keep parts of the same unit together. If so, this argues that more than one was made.

The final post on this topic (Part 3) will focus on dividers and calipers where the legs are locked by a mechanism above the joint.