speedometer cable/drive part

[bex1151]

I am trying to identify and source the small cylindrical part that slips into the tachometer & speedometer drives to engage the related dashboard gauge cables.  I have not been able to find any reference to the necessary part in any of my maintenance/parts references.  The attached photo shows a part I found in a pile of nuts and bolts that seems to do the job.  Is it the part I need?  What is the correct part name and where can I buy new ones? 

[Jam2]

Would it be worthwhile speaking to one of the specialist firms who make or repairs the cables, e.g. http://www.speedograph-richfield.com/