I guess I will add my 2 cents worth.

My EMCO 7 inch lathe with milling column has a round column and it
does not loose zero when raised/lowered. It has a large full length
key attached the column and adjustable gibs in the head. To rotate the
head, the round column is released at the base and the column and head
all are rotated.

However, my Grizzly mill/drill with a round column certainly looses
zero when raised/lowered. The geared key on the column is attached to
the column only at the top and bottom by the wedge shaped ends of the
key. When the head of this machine is rotated, the key also moves
slides around the column.

Potentially, the entire Grizzly column and head could be turned like
the EMCO. I have not tried it. Some while back(years?) there was an
article in a home machinist magazine about screwing the geared key to
the column to minimize the loss of zero when moving thead. I don't
think this would help much bacause there are no gibbs to take up the
remaining slop.

By the way, the problem of spotting drill lenght vs. jobber length
drills was solved when I got several 4-6 inch spotting drills at an
estate sale.

Paul in Redmond, Oregon







Gary Coffman wrote in message . ..
On Sun, 9 Nov 2003 14:58:16 -0600 (CST), (Leo Reed) wrote:
No one seems to address the mini mill vs. the Drill mill (rf-30)
question.

Never used a RF-30... impressive machine... too big for my shop. But the
round column does not impress me.

You're right not to be impressed by the round column. You do lose
your zero when you raise or lower the head. But that 2 hp head does
have some grunt. It'll take cuts that would destroy the mini-mill. The
work envelope is much larger too.

Since I got my big knee mill, my RF-30 is mostly used as a heavy
drill press. But before that it was my main mill, and I cut a lot of
metal with it. It is capable of good work, once you learn how to
work around its ideosyncracies.

Gary