Repairing the Belt Splicer

In the process of getting Holtzapffel No. 1636 up and running safely we almost immediately found ourselves facing the issue of how best to deal with drive belts.   When the machine was built in 1838 the only viable options were leather and gut., and the pulleys on the lathe were made elegantly small with a V groove to accommodate those choices.    

The leather belt that came with the lathe was joined by a staple typical of those used in the past for light duty on sewing machines.  When the belt was installed it broke almost immediately as the leather had deteriorated.   New leather belting was obtained, cut to length and installed, however, the connecting staple stretched under the tension required to prevent slippage.   

Stretched staple on new round belting. 

When we mentioned the problem to Frank Dorion, he immediately suggested a tool he’d seen advertised in an old Levin lathe catalogue and had duplicated for use on his own rose engine.  He was kind of enough to show up the next time with a “kit” of steel parts ready for machining and a sketch of what needed to be done.   Our staff set the Bridgeport milling machine into action and produced the prescribed parts, as having such a tool in the kit of Holtzapffel No. 1636 seemed prudent. 

Page from Levin catalogue showing the tool no longer available.  

With the splicing tool in hand, we went about making a spliced and sewn belt that would withstand the tension needed to drive the lathe without slipping and be sufficiently durable to take the lathe into the next generation of use.    

Belt splicer tool shown with side clamp removed to show clamping groove.

Belt clamped into splicer, ready to make tapered cut.
With belt clamped by a locking screw (knob on left side of splicer), a razor knife is used to accurately taper both ends of the belt. 
Finished taper cut.
Contact cement is then applied to both ends of the belt as directed in the glue’s instructions.  
The shorter clamp section holds one end of the splice steady in the clamping groove while the other end of the splice is positioned over it. Once the two ends are joined with the contact cement, the longer clamp is applied and holds the splice under pressure until the glue has cured thoroughly.    
The shorter and longer clamp sections holding the splice till the glue cures.
Belt installed showing V groove in pulley.