There is a recommended assembly Nut tool for this series of banana jacks. The tool is listed as CT2246A.
One dimension missing from the tool drawing is the Outside diameter of the Nut tool. We measured one in Our warehouse at the protruding points of the nut tool. Our diameter measurement is 14.53mm.
This will work on all variations of the CT2238- Part number below.
Applicable Part Numbers
CT2238-2 CT2238-4 CT2238-9 CT2238-5 CT2238-6 CT2238-7 CT2238-8 CT2238-1 CT2238-0
BKCT2238-2-ND BKCT2238-4-ND CT2238-9-ND BKCT2238-5-ND BKCT2238-6-ND CT2238-7-ND CT2238-8-ND CT2238-1-ND BKCT2238-0-ND