"Roger Shoaf" wrote in message
...

snip

Sure you will get less walk. The surface incontact with the work is only
the small portion of the end face of the tool. Your X any Y gibs are
locked
and your quill gib is snugged, so you have very little room for wiggle.
The feed is linear to your hand and you can feel if you start to over do
it
easier than when you are turning a crank.

Also bu unly taking .010" at a time you will be able to plunge fairly
quickly and you only have to do it 7 or 8 times.

If the mill does flex sideways, you will end up with only a small
deviation
twords the bottom of the slot and it will only be a couple of thou wide
and
deep. This gives you a straight wall of at least 80%.

Right. Forgot you can lock X *and* Y this way. Maybe I won't even have to
use the fine feed this way.

snip


Ok let me see if I can explain. You have done all of your plunges, and
you
now swap your 1/4" end mill for a 3/16" end mill. Since the diameter of
the
new end mill is smaller, You would start from the right side of the slot
and
plunge it to depth or raise the table to bring the mill to depth. Your
cutter should be then centered in the slot and you move the table about
.025
away from you and the cutter should then be .007 from the kiss point.

You now lock the gib, and loosten the side travel gib, and re-snug it so
it
allows you to turn the crank, but with some resistance. Now feed the work
into the cutter. You are going to get a little flex in the end mill but
you
are taking a small bite and all of the flex is going to be away from your
final desired dimention so you still have room to make a clean up cut.
When
you get near the end of your pass, you are going to run out of metal to
cut
as you enter the quarter inch hole. Now you can take a clean up pass back
doing climb milling or extract the cutter and restart from the right side
of
the slot but this timetake about a .003 bite. The bottom of the slot will
be narrower than the top but the end mill will be trying to remove less
material so the flex-away will be a lot less and the side wall should be
really close to square.

Now reset to make your final clean up cut, perhaps upping the speed a
notch
this time you will be climb milling and you should clean up really close
to
what you want to be at.

Now you do the same thing on the other side of the slot.

Got it! The centre line is the reference. Makes sense.

snip.

Your dial is set and locked from when you did the plunge cuts, so you
should
be able to just adjust the crank to accomidate the smaller cutter.

When you get ready to cut the back side of the slot, you need to be
cognisant of the backlash in the feed screw so when you make your first
pass
onthe back side you can sneak up on the firast pass and you will be able
to
keep the slot width from going too wide.

I try to use dial indicators whenever possible. I guess backlash comes into
it even on the near side, depending where one left the wheel to start with.

True - my tolerancies are quite - tolerant. However, the reason I am
beating
this topic to death is to know the right way the next time when the job
is
not so forgiving.

Practice on some scrap to hone the technique, and pretty soon it will
become
second nature.

I learned this technique from a very fussy german mold maker when my task
was to cut the pockets in mold bases 6 inches thick. He started by having
me cut to within .005" of the desired size and then he did the final
sizing
until I had the tecnique down pat, then he let me finish them up to final
size.

Now I understand it. Thanks.

True. At this point it is sometimes difficult to tell which are the
limitations of the machinery and which of the operator. What I got so far
is
a mixture of both.


Practice, and observe the results, and be willing to learn from your
mistakes. Soon the techniques will become second nature, you will get
over
confident has some part you have many hours into and your mistakes will
become fewer and farther in-between.

Also when you by the next machine that has less slop you will really be
appreciative of all of your futzing time. I remember the firs project I
made on a Hardenge lathe Wow!!!

Yes. I might even discover what these quills and tables going up and down
are all about....:-)

--
Michael Koblic
Campbell River, BC

"Michael Koblic" wrote in message
...

Do you do this with 2-flutes or 4-flutes?

Here is some basic reading on the subject:
http://www.finelinehair.com/home/end...menclature.pdf

However for your machine, technique is usually going to be the biggest
factor in the selection of the number of flutes, so I would keep it kind of
simple. Select a two flute if you need it to cut in the center, other wise a
4 flute should work just fine.

The number of flutes and teh geometry of the flutes gets really critical
when you are talking high speed production runs and the like but it is not
going to be much of an issue for you.

One important factor is going to be the length so use the shortest length
you can for greater rigidity.


--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

On Oct 10, 1:34*am, "Michael Koblic" wrote:

Yes. I might even discover what these quills and tables going up and down
are all about....:-)

--
Michael Koblic

You have a Sieg X2, right?

The quill feed makes a mill handier as a drill press but on an old
worn machine like mine it's an extra wear surface contributing to
inaccuracy. In geometric terms your single dovetailed Z axis should be
more precise and rigid. I suspect that with heavy production use it
might wear faster than a quill plus a knee supported at its center of
gravity. Unless you need to duplicate complicated broken machine parts
you may have a better hobby mill.

The Clausing has too many adjustment joints to be solid enough for
heavy cuts. You can see them in use here, http://www.lathes.co.uk/clausing%20vertical/
Like a Shopsmith or my Toolmaker surface grinder, each additional
degree of freedom that increases versatility also decreases stiffness.

jsw

On Oct 10, 1:45*am, "Michael Koblic" wrote:
Jim Wilkins wrote:
...
0.1" and 0.2" are convenient to move without reading the dial and
about the maximum the endmill will cut freely, since the center
doesn't cut as well.

Do you do this with 2-flutes or 4-flutes?

Michael Koblic
Campbell River, BC

At work, whatever is still sharp. I'm an electronic tech and don't
usually get the big jobs so what milling I do there is more like light
hobby work. At that level feed and depth of cut have more effect than
the number of flutes. I speed up the crank until the tool or machine
starts to complain, then back off. On that lot of plastic boxes for in-
house test use the slots were only for clearance so I pushed the cut
to see what would happen.

I think the idea is to make each cutting edge take a healthy bite
because edges wear more from distance travelled than thickness
removed, then have enough flute spacing for the chip produced. In
practice there isn't that much difference between 2 and 4 or the 8
flutes on my shell mill, they all work well with the right feed, speed
and depth of cut.

jsw

On Sat, 10 Oct 2009 05:13:16 -0700 (PDT), Jim Wilkins
wrote:

On Oct 10, 1:34*am, "Michael Koblic" wrote:

Yes. I might even discover what these quills and tables going up and down
are all about....:-)

--
Michael Koblic

You have a Sieg X2, right?

The quill feed makes a mill handier as a drill press but on an old
worn machine like mine it's an extra wear surface contributing to
inaccuracy. In geometric terms your single dovetailed Z axis should be
more precise and rigid. I suspect that with heavy production use it
might wear faster than a quill plus a knee supported at its center of
gravity. Unless you need to duplicate complicated broken machine parts
you may have a better hobby mill.

The Clausing has too many adjustment joints to be solid enough for
heavy cuts. You can see them in use here, http://www.lathes.co.uk/clausing%20vertical/
Like a Shopsmith or my Toolmaker surface grinder, each additional
degree of freedom that increases versatility also decreases stiffness.

jsw


Not if they are tightened before starting a cut.

Btw..I have an 8540 horizontal Clausing mill for sale..in decent shape
if anyone is interested. Ill even toss in some tooling, arbors etc etc.


Gunner

"Lenin called them "useful idiots," those people living in
liberal democracies who by giving moral and material support
to a totalitarian ideology in effect were braiding the rope that
would hang them. Why people who enjoyed freedom and prosperity worked
passionately to destroy both is a fascinating question, one still with us
today. Now the useful idiots can be found in the chorus of appeasement,
reflexive anti-Americanism, and sentimental idealism trying to inhibit
the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

Jim Wilkins wrote:

You have a Sieg X2, right?

The quill feed makes a mill handier as a drill press but on an old
worn machine like mine it's an extra wear surface contributing to
inaccuracy. In geometric terms your single dovetailed Z axis should be
more precise and rigid. I suspect that with heavy production use it
might wear faster than a quill plus a knee supported at its center of
gravity. Unless you need to duplicate complicated broken machine parts
you may have a better hobby mill.

The Clausing has too many adjustment joints to be solid enough for
heavy cuts. You can see them in use here,
http://www.lathes.co.uk/clausing%20vertical/
Like a Shopsmith or my Toolmaker surface grinder, each additional
degree of freedom that increases versatility also decreases stiffness.


The X2 is what it is. Looking in Grizzly catalog the shipping weight is 149
lbs. The next one up (X3??) is 418 lb.
Putting an indicator on a mag base on the table with the point against the
column (not the spindle or head, just the column) about 2/3 up I can make it
flex 0.020" in both directions.

I do not know how it compares with anything else (which, in a sense, is why
I started this thread in the first place) but I suspect that the difference
will be significant even against the X3.

I know that people pour concrete into their column and devised all kinds of
brackets to strengthen it - I am not sure if that amounts to flogging a dead
horse.

At this point it does not matter too much as few thou either way are not
kill me. If it ever becomes an issue one will probably consider an upgrade.

--
Michael Koblic
Campbell River, BC

On Oct 10, 6:39*pm, "Michael Koblic" wrote:
...
At this point it does not matter too much as few thou either way are not
kill me. If it ever becomes an issue one will probably consider an upgrade.

--
Michael Koblic
Campbell River, BC

I really only have chatter problems with deep cuts with 2-flute end
mills or large drill bits cutting pipe, with the knee all the way down
for clearance. Then the dumbbell-shaped head and motor assembly twists
back and forth. When tightening everything and reducing the feed don't
help I drop to the lowest speed, which usually kills the resonance.

The head rotates 0.001" / 60 Lbs relative to the lowered and clamped
table.

jsw

On Oct 10, 11:39*pm, "Michael Koblic" wrote:


I know that people pour concrete into their column and devised all kinds of
brackets to strengthen it - I am not sure if that amounts to flogging a dead
horse.

--
Michael Koblic
Campbell River, BC

Filling the column with concrete will increase the weight and reduce
chatter. If I were going to fill the column with concrete, I would
include as much rebar as I could. Especially trying to have the rebar
next to the wall of the column. That might increase the stiffness a
noticeable amount.


Dan