On 2008-02-26, Brian Lawson wrote:
On Mon, 25 Feb 2008 17:38:27 -0600, Rex wrote:
I found this among my Aloris style blocks, and it's foreign to me.
Can anyone identify it?
http://www.metalworking.com/dropbox/
filename is 'tool block cutoff 004a.jpg'
Hey Rex,
Not a lot of help, but it is somewhat similar to a Dickson I have on a
15" lathe. The one you have has squares guides, where mine has
EXTERNAL V's , not internal like an Aloris or Phase II type.
Aloris and Phase II styles are locked in place by dropping them onto
the tool-post until bottoming the adjusting collar atop the
tool-holder, and rotating the locking handle on the tool post, which
in turn "pushes" the holding/locking cam "out" against the back of the
tool-block and jams it tightly into the V-grooves. The locking handle
is centralized on the tool-post and turning it forces ALL in turn,
usually only two placements. You can't lock two tool-holder blocks on
at once, as the cam is extending one "pusher" as it retracting the
other(s).
That depends on the version. What you are describing is the
"piston" style, while most Aloris genuine ones are "wedge" style, which
works by making the dovetail wider and thus drawing in the toolholder to
firmly press against the toolpost, instead of pushing it out and
depending on the wings of the dovetail for rigidity. Almost all modern
Aloris toolposts are wedge style, though they *did* make a piston style
one in the earlier years. Most of the clones are offered in your choice
of piston style (cheaper) or wedge style (more expensive). I got the
wedge style, and am glad that I did.
However, the precise point at which the dovetail is wide enough
to lock up is probably slightly different between two holders on
different dovetails, and the tools interfere with each other anyway, so
one holder at a time is still the rule, even with the wedge style
toolpost.
Note that a piston style toolpost allows the locking handle to
rotate a full 360 degrees around the toolpost when there is no tool
holder installed -- and it has been known to get the handle and knob
into the path of the chuck jaws. The wedge style has a limited swing
for the handle of something like 120 degrees.
The Dickson operates slightly differently. Mine can hold three
different tool-holder blocks at one time (three faces), and I believe
some can do four or more. The tool-holder block is dropped onto a
vacant side, into the slots on the tool-post, and the tool-holder
drops down until the adjusting collar/ring comes to the stop/lock cam
slightly above the tool-post top. Without a pix to send you, it is a
bit difficult to explain what that is. Anyway, when the tool-holder
is in position, the individual locking cam is turned, and it forces a
cam/piston IN to lock the block in place, and at the same time grabs
above and below the adjusting collar/ring to REALLY set the tool
height to the place you adjusted it to at some previous time. This
allows as many cutting tools as you can fit without interfering with
one another.
The "interfering with each other" is the problem. I have a
Dickson style which is smaller -- for an Emco-Maier Compact-5/CNC lathe,
and it has only two stations, but I can still only use one at a time.
One station is for turning, the other for boring and facing, so the
tools point in directions to cross and interfere with each other.
I guess that with a three-station toolpost, you could mount two
tools on the opposite stations, leaving the boring/facing station empty.
I'm not sure how useful that would be, however.
If you still really want to see one, I'll take some pix of mine and
sent them to you.
There have been recent discussions of this very style, with
links posted pointing to images, so just go back and look at the series
of articles about a Clausing 5914 lathe (which the poster received with
a Dickson style toolpost -- much beat up as it turns out).
Enjoy,
DoN.
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