Adaptor for scaffolding

1. A scaffold assembly comprising:

a first scaffold having a stack pin;

a second scaffold having an opening; and

an adaptor attaching the first scaffold to the second scaffold, the adaptor comprising a sleeve having a first end, a second end, and an orifice at the second end receiving the stack pin, an exterior surface including a tapered section at the first end inserted into the opening to stack the second scaffold on top of the first scaffold, and a threaded hole in the sleeve adapted for receiving a set screw therethrough so that the set screw engages the stack pin received in the orifice to secure the adaptor to the stack pin, the threaded hole comprising a first hole, the sleeve including a second hole positioned for alignment with a hole in the second scaffold so that a pin can be received through the hole in the second scaffold and the second hole in the sleeve to secure the second scaffold to the adaptor, the sleeve having an interior surface and a shoulder formed in the interior surface separating the sleeve into upper and lower portions, the lower portion having an inner diameter smaller than an inner diameter of the upper portion.

2. An assembly as set forth in claim 1 further comprising a radial clearance of about 0.2 mm between the inner diameter of the lower portion the sleeve and an exterior surface of the stack pin.

3. An assembly as set forth in claim 2 wherein said lower portion of the sleeve has an inner diameter of about 26 mm.

4. An assembly as set forth in claim 3 wherein at least a portion of the sleeve has an outer diameter of about 32 mm.

5. An assembly as set forth in claim 1 in combination with the set screw, the set screw having a threaded exterior surface for mating with the threaded hole in the sleeve to secure the adapter to the stack pin.