You probably know this, but Ettco is still in business,
http://www.ettco.com/
and they still make tapping heads.

You might contact them. They sent me a parts diagram for my 1930's model

-- Greg

"Aribert" wrote in message
om...
Last week I went to a local machinery auction and for once there were
more lots than interested bidders. I bid and won a bench grinder for
$5, the auctioneer included the two prior lots that did not sell for
$5. One of those two lots consisted of an antique tapping head. The
brand name is ETTCO, Eastern Tube & Tool Co. w/ a patent lable of Aug
1924. I have never used a tapping head before - I have occasionaly
....