Face mill, flycutter, etc.
 

Hello all,

I finally used the cheapo shell/face/whatever-it-is cutter that came
with my mill, and I'm rapidly getting hooked :) So far, I am cutting
plastic and using it for squaring.

At 3 inch diameter, the cutter is large enough to reveal that my head
leans to the right (fortunately the mill leans much less than its
owner/operatorg). I'm not going to mess with it just yet, but I am to
the point of wanting recommendations for shim material. Is there a
particularly smart (or stupid) way to buy shims?

For a replacement of the cutter, the choices appear to be a flycutter or
an indexable face mill. I am leaning toward a face mill; it strikes me
as being more robust and safer than a flycutter. Indexable mills are a
little more expensive than I might like. The price might get me to
compromise on 2 inch diameter, which would have the side benefit of
reducing the effects of column misalignment.

Any recommendations for a good choice from Enco? Clearly the face mills
are designed for a particular insert type, but I have no clue whether I
should start by picking the face mill or the type of inserts???

Bill

Face mill, flycutter, etc.
 

"Bill Schwab" wrote in message
ink.net...
Hello all,

I finally used the cheapo shell/face/whatever-it-is cutter that came
with my mill, and I'm rapidly getting hooked :) So far, I am cutting
plastic and using it for squaring.

At 3 inch diameter, the cutter is large enough to reveal that my head
leans to the right (fortunately the mill leans much less than its
owner/operatorg). I'm not going to mess with it just yet, but I am to
the point of wanting recommendations for shim material. Is there a
particularly smart (or stupid) way to buy shims?

For a replacement of the cutter, the choices appear to be a flycutter or
an indexable face mill. I am leaning toward a face mill; it strikes me
as being more robust and safer than a flycutter. Indexable mills are a
little more expensive than I might like. The price might get me to
compromise on 2 inch diameter, which would have the side benefit of
reducing the effects of column misalignment.

Any recommendations for a good choice from Enco? Clearly the face mills
are designed for a particular insert type, but I have no clue whether I
should start by picking the face mill or the type of inserts???

Bill

Fly cutters offer a wonderful way to machine without expense. They may be
correspondingly slower than multi-toothed cutters, but there's an offset if
you choose to run brazed carbide tools, so your surface speed can be
increased considerably. You can often get a far superior finish with a
fly cutter than other types, depending on the circumstances at hand.
Bottom line: If you have no money issues, multiple toothed cutters are
great, assuming you have the power and rigidity at hand to justify them.
Otherwise, stick with fly cutters, which are easily sharpened by hand, and
can be tailored to your needs easily.

Don't put off squaring the head of your mill with the table. It's like
painting over rust. Regardless of the size of the cutter, the amount of
error still exists, it's just that the indicator, the step in the cut, is
reduced. Same incidence of angle, though.

It's dead easy to determine how much shimming you need. Spin a DTI on the
table of the mill, mounted in the spindle in a drill chuck, so you have
something to grip. The indicator should be mounted such that it generates
a circle the same size as the mounting boss at the base of the column.
That will reveal not only where you must shim, but how much. Install the
appropriate amount of shim to establish a 0-0 reading in all positions. You
may have to use small strips @ 90 degree intervals to get it right. I
think you get the idea.


Harold

Face mill, flycutter, etc.
 

Harold,

Fly cutters offer a wonderful way to machine without expense. They may be
correspondingly slower than multi-toothed cutters, but there's an offset if
you choose to run brazed carbide tools, so your surface speed can be
increased considerably. You can often get a far superior finish with a
fly cutter than other types, depending on the circumstances at hand.
Bottom line: If you have no money issues, multiple toothed cutters are
great, assuming you have the power and rigidity at hand to justify them.
Otherwise, stick with fly cutters, which are easily sharpened by hand, and
can be tailored to your needs easily.

Fair enough. Besides, the import flycutters are cheap, and I really
should have one, so I will probably start there and splurge on a face
mill if the flycutter gives me the creeps. I remember cautions about
the relatively large area of blur that is in fact a serious injury
waiting to happen, and some mention of a guy named "Lefty". While I
suspect that particular "Lefty" was largely a mythical figure, I note
that myths are often based in truth if not fact.



Don't put off squaring the head of your mill with the table. It's like
painting over rust. Regardless of the size of the cutter, the amount of
error still exists, it's just that the indicator, the step in the cut, is
reduced. Same incidence of angle, though.

It's dead easy to determine how much shimming you need. Spin a DTI on the
table of the mill, mounted in the spindle in a drill chuck, so you have
something to grip. The indicator should be mounted such that it generates
a circle the same size as the mounting boss at the base of the column.
That will reveal not only where you must shim, but how much.

When you put it that way, it does sound easy. The holes appear to be at
about 4.5x9 inches on center. The 4.5 in gap (if that's really what it
is) just barely fits between the slots (on the table vs. "in" the
slots). Or should I use the outside dimensions of the flange? The
inside dimension seems most appropriate, but I'm not sure I want to
spend that much time under 700 lbs of metal that is dangling on a nylon
sling.

It sounds like I need to mount the DTI, use the fine feed to move
up/down, and rotate the indicator to decide which corner is highest, and
then decide what if anything to add at the other corners. Loosen the
bolts, use my hoist to partially lift the head/column, insert shims,
lower, tighten and check. Is that reasonable?

Should I use any particular torque when replacing the bolts, or just
give a reasonable yank on an appropriate wrench? Speaking of wrenches,
I have a 15/16 socket that might be oversized, and a 22 mm compound
wrench that doesn't quite fit. The bolts are listed as being 5/8, but I
have seen metric sized heads on imperial bolts :( Anybody know what
fits it? With 15/16 being slightly loose and 22 mm too small, I guess
23 mm would be ok.



Install the
appropriate amount of shim to establish a 0-0 reading in all positions. You
may have to use small strips @ 90 degree intervals to get it right. I
think you get the idea.

I think so, except for the 90 degrees part. I am thinking of splurging
on slotted SS shims, but will want to make at least a first measurement
to get an idea of how much material I will need. I suspect it's not
much, but might be surprised.

Thanks!

Bill

Face mill, flycutter, etc.
 

"Bill Schwab" wrote in message
nk.net...
snip----
I remember cautions about
the relatively large area of blur that is in fact a serious injury
waiting to happen, and some mention of a guy named "Lefty". While I
suspect that particular "Lefty" was largely a mythical figure, I note
that myths are often based in truth if not fact.

Chuckle!

Yeah, they're quite intimidating, but when applied properly, they're no more
dangerous than other cutters. One learns to keep hands away----and
always point your acid brush such that it can't be pushed into your hand.

It's dead easy to determine how much shimming you need. Spin a DTI on
the
table of the mill, mounted in the spindle in a drill chuck, so you have
something to grip. The indicator should be mounted such that it
generates
a circle the same size as the mounting boss at the base of the column.
That will reveal not only where you must shim, but how much.

When you put it that way, it does sound easy. The holes appear to be at
about 4.5x9 inches on center. The 4.5 in gap (if that's really what it
is) just barely fits between the slots (on the table vs. "in" the
slots). Or should I use the outside dimensions of the flange? The
inside dimension seems most appropriate, but I'm not sure I want to
spend that much time under 700 lbs of metal that is dangling on a nylon
sling.

The information you are looking for is how much it will take to tilt the
column until it is at right angles to the table-----which would likely best
be checked at the point of the bolts. I get the idea that the bolts you
speak of are not spaced @ 90 degrees, so determine the bolt circle, and
swing the indicator in that arc.

You want the indicator to make contact on the front and back of the table,
and at each side @ 90 degrees. If you find the T slots are roughly the
same spacing as the circle you must spin (the bolt circle of the base of the
column), move the saddle until the circle permits contact of the indicator
when it's on each side of center.

You shouldn't have to lift the head off the machine. Just break the bolts
loose (don't take them out if possible)and tip the head slightly, so you can
insure everything is clean under the flange, tipping once left and once
right, then tighten the bolts again and check with the indicator.
Hopefully you understand that once you touch the indicator to the table, you
don't move the quill. Lock it so it can't move, then rotate the spindle.
What you want to see is how much variation there is from dead true, which is
the condition you hope to achieve. Depending on the quality of your
indicator, this can be troublesome. Lots of indicators don't enjoy being
rotated across slots, so if you can make a setup whereby your indicator
trails off instead of approaches the slots sideways, that's the best way to
go. Don't preload the indicator by much, so it doesn't have to move far
before the ball is on the table as it crosses the slots. Rotate by hand,
slowly.

Should I use any particular torque when replacing the bolts, or just
give a reasonable yank on an appropriate wrench?

Once you've shimmed the base, tighten the bolts well, then check again with
your indicator. While everything should change according to the amount of
shimming you do, things like this have a way of coming out somewhat
differently than you planned. Don't quit until you have a variation on your
indicator of less than a thou. Shoot for dead nuts.

I have no idea about torque specs, but once you have the flange well
tightened, any further tightening shouldn't affect your indicator reading.
If it does, something isn't right. When you're finished, make sure the
bolts are well tightened. Use good sense----tighten them, but don't try to
break them. Remember, the forces of the cuts you make are transmitted
through these bolts, and you don't want any movement.

Install the
appropriate amount of shim to establish a 0-0 reading in all positions.
You
may have to use small strips @ 90 degree intervals to get it right. I
think you get the idea.

I think so, except for the 90 degrees part. I am thinking of splurging
on slotted SS shims, but will want to make at least a first measurement
to get an idea of how much material I will need. I suspect it's not
much, but might be surprised.

What you're likely to discover is that you need different thicknesses for
each position. If you use .001" shim stock and stack it, you would probably
have all you needed to get the job done. No need to buy various
thicknesses. You should be able to cut shims with scissors that are maybe
an inch wide that have a slot for the bolt and will slip under each bolt
position to raise it. One, the lowest point on the indicator (hopefully at
one of the bolt positions), can be your reference point, and won't need to
be shimmed. The other three positions (where your bolts are) will each
likely need a shim of different thickness. That's what your indicator will
tell you-----how much-------and where.

Thanks!

Bill

Welcome.

Let us know how it turns out.

Harold

Face mill, flycutter, etc.
 

Harold,

The information you are looking for is how much it will take to tilt the
column until it is at right angles to the table-----which would likely best
be checked at the point of the bolts. I get the idea that the bolts you
speak of are not spaced @ 90 degrees, so determine the bolt circle, and
swing the indicator in that arc.

They are not at 90 degrees. It's no big deal but it leads to a question
below.


You want the indicator to make contact on the front and back of the table,
and at each side @ 90 degrees. If you find the T slots are roughly the
same spacing as the circle you must spin (the bolt circle of the base of the
column),

Let's say the bolts, seen from the center of the column, are at 10,2,4,8
o'clock positions. Do you want contact at 9,12,3,6 or 10,2,4,8 (same
directions as the bolts)? I'm assuming the latter, but I might be
missing something.


move the saddle until the circle permits contact of the indicator
when it's on each side of center.

Back to the clock, say I'm at 8 and 10 stubbornly sits over a slot. Is
it ok to move the table to put table surface under the 10 position?
Again, I think it will be ok by 0.1 inch or so. Failing that, I can
scale the radius up a bit to avoid the slots and then scale down the
readings. My hunch is that would be better than moving the table
between readings, but let me know if that's making it harder than necessary.


You shouldn't have to lift the head off the machine.

Understood. I was thinking of the crane as a way to tip the head more
than lift it.


Just break the bolts
loose (don't take them out if possible)and tip the head slightly, so you can
insure everything is clean under the flange, tipping once left and once
right, then tighten the bolts again and check with the indicator.

So you want me to clean up the flange before doing the first
measurement? That makes sense now that I think about it; otherwise
shimming might knock out the grit that was holding the head in place =:0


Hopefully you understand that once you touch the indicator to the table, you
don't move the quill. Lock it so it can't move, then rotate the spindle.

Yes, with a twist. I have found it a lot easier to rotate the zero on
the indicator to about where I want it and then preload by moving the
table rather than trying to fiddle with the indicator dial itself - the
forces required to turn it are big enough to cause trouble. I am
assuming that here I would pick a likely preload, scan once around to
find the corner to use for a reference, move the quill to zero it, and
then start reading.


What you want to see is how much variation there is from dead true, which is
the condition you hope to achieve. Depending on the quality of your
indicator, this can be troublesome. Lots of indicators don't enjoy being
rotated across slots, so if you can make a setup whereby your indicator
trails off instead of approaches the slots sideways, that's the best way to
go. Don't preload the indicator by much, so it doesn't have to move far
before the ball is on the table as it crosses the slots. Rotate by hand,
slowly.

Got it. Make the preload small enough that the tip hits the bevels
rather than falling into the slots.

Not that I intend to buy one ASAP, but are the name brand indicators
that much better than the imports? In addition to the caliper
(mentioned below), I ordered a backup import DTI. I almost managed to
snag it on a step clamp last week and decided that having a second one
on hand would be a good idea. Smashing a $40 indicator would be
annoying; I'd rather not think about taking out a Starrett.


Let us know how it turns out.

Will do. I will probably get some SS shim stock first in the hopes of
getting it all done in one session. Also, I recently ordered a 12 inch
import caliper; having it will help me measure the larger bolt separation.

Thanks!

Bill

Face mill, flycutter, etc.
 

"Bill Schwab" wrote in message
ink.net...
Harold,

The information you are looking for is how much it will take to tilt the
column until it is at right angles to the table-----which would likely
best
be checked at the point of the bolts. I get the idea that the bolts
you
speak of are not spaced @ 90 degrees, so determine the bolt circle, and
swing the indicator in that arc.

They are not at 90 degrees. It's no big deal but it leads to a question
below.

When you dial a tilting head, the 90 degree interval is important. I
understand that your bolts are not equally spread, which I gathered when you
gave the dimensions. No big deal----treat each bolt as a critical
position----because that's where you'll place your shims.



You want the indicator to make contact on the front and back of the
table,
and at each side @ 90 degrees. If you find the T slots are roughly the
same spacing as the circle you must spin (the bolt circle of the base of
the
column),

Let's say the bolts, seen from the center of the column, are at 10,2,4,8
o'clock positions. Do you want contact at 9,12,3,6 or 10,2,4,8 (same
directions as the bolts)? I'm assuming the latter, but I might be
missing something.

See above. Truth be known, if the machine is right, it doesn't matter
because the reading should be 0 regardless of location. The point of
checking location as noted is strictly so you know how much shim at that
particular position. Otherwise it makes no difference, not as long as you
can relate the readings to a position.



move the saddle until the circle permits contact of the indicator
when it's on each side of center.

Back to the clock, say I'm at 8 and 10 stubbornly sits over a slot. Is
it ok to move the table to put table surface under the 10 position?
Again, I think it will be ok by 0.1 inch or so. Failing that, I can
scale the radius up a bit to avoid the slots and then scale down the
readings. My hunch is that would be better than moving the table
between readings, but let me know if that's making it harder than
necessary.

It shouldn't make any difference if you move the table, or not, because it
should move without up or down change, at least in theory.

What I do is set the spindle such that it's not centered over one of the T
slots, at which time I have contact at the proper places. You need not be
in the center of the table. It's assumed that the table is flat and uniform,
so you should be able to dial it anywhere, so long as you can make contact
with your indicator as required. For me, that's at 3, 6,9,12. For you, in
this instance, it would be relative to your bolt locations. As long as you
swing a circle that is similar to your bolt pattern, and make contact at the
same positions on the table as you have bolt locations, you've done all that
is necessary.

Just break the bolts
loose (don't take them out if possible)and tip the head slightly, so you
can
insure everything is clean under the flange, tipping once left and once
right, then tighten the bolts again and check with the indicator.

So you want me to clean up the flange before doing the first
measurement? That makes sense now that I think about it; otherwise
shimming might knock out the grit that was holding the head in place =:0

Yep! There's no guarantee that there's not something between the two
surfaces. Clean them well and deburr if necessary. Could be you'll have to
lift the entire head and column assembly, but maybe not. It makes no sense
to go to a lot of trouble to square the column when it's subject to change.
Regardless of the degree of error, if you get down to clean surfaces, you'll
have something concrete with which to work. Screwing around with it if
it's dirty, or has some dings, can be very frustrating. Every time you make
a change, it comes out differently than you expect. You end up wasting too
much time chasing it.


Hopefully you understand that once you touch the indicator to the table,
you
don't move the quill. Lock it so it can't move, then rotate the
spindle.

Yes, with a twist. I have found it a lot easier to rotate the zero on
the indicator to about where I want it and then preload by moving the
table rather than trying to fiddle with the indicator dial itself - the
forces required to turn it are big enough to cause trouble. I am
assuming that here I would pick a likely preload, scan once around to
find the corner to use for a reference, move the quill to zero it, and
then start reading.

I usually don't worry much about zeroing an indicator, but when I do, I also
adjust it then set it by (in my case) raising the knee. It's far more
precise. Assuming I don't zero the indicator, I make a mental note of
where the finger points and go accordingly. It's all a matter of your
personal work habits. Establishing zero helps avoid errors.

Start out with minimum contact and adjust as necessary. I don't expect
you're going to find a huge discrepancy, and with luck it won't be. I'm
thinking only a thou or two, so you should be able to pick any spot and
preload a couple thou and have it work. No big deal if you have to add a
couple more thou.


Not that I intend to buy one ASAP, but are the name brand indicators
that much better than the imports?

I'm not familiar with any of the imports (aside from the B&S BestTest, which
is/was Swiss made, and is amongst the best on the market), so I hesitate to
comment. One thing I will comment on is the Starrett Last Word. If you
don't have one, don't buy one. While the vast majority of my tools are
Starrett, including one of the Last Word indicators, I do not recommend it
to anyone for anything. The design sucks, and always has. They're quite
insensitive, generally performing very poorly under a thou. There are far
better indicators on the market. By sharp contrast, I have several of
their long travel indicators and recommend them highly.

In addition to the caliper
(mentioned below), I ordered a backup import DTI. I almost managed to
snag it on a step clamp last week and decided that having a second one
on hand would be a good idea. Smashing a $40 indicator would be
annoying; I'd rather not think about taking out a Starrett.

Thanks!

Bill

Welcome!

Harold

Face mill, flycutter, etc.
 

Harold,

It shouldn't make any difference if you move the table, or not, because it
should move without up or down change, at least in theory.

What I do is set the spindle such that it's not centered over one of the T
slots, at which time I have contact at the proper places. You need not be
in the center of the table. It's assumed that the table is flat and uniform,
so you should be able to dial it anywhere, so long as you can make contact
with your indicator as required. For me, that's at 3, 6,9,12. For you, in
this instance, it would be relative to your bolt locations. As long as you
swing a circle that is similar to your bolt pattern, and make contact at the
same positions on the table as you have bolt locations, you've done all that
is necessary.

Thanks for the clarification!

Bill