ebay can be of help. Look for d1-6 in Business and Industrial section.

example

http://cgi.ebay.com/12-Skinner-Lathe... 286.m20.l1116

On 2008-10-14, Michael Koblic wrote:
Looking at chucks from various sources they seem to be mounted on lathe
spindles in a variety of ways. Most of the time I can grasp what is going on
but some of the designations stumped me: What is the D 1-4, D1-6 etc.,
mount? Books and Google are no help.

Thanks,


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