Hello all,

With respect to dial test indicators, I am struggling with understanding
auto-reverse. It appears to be good, but what is it? I see lots of
mention of not needing to flip a lever; are such indicators obsolete
now? Is there any reason one would want one?

It might help to start w/ my import's behavior: the dial advances
clockwise from zero regardless of the direction of motion of the point.
It looked weird at first (the dial markings suggest it would do
something else), but I figured it was probably by design, having
something to do with an indicator version of backlash near zero.

When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and
work relative to that. I don't bother to move the dial, though it might
be smart to "permanently" offset it so that I'm working at zero vs. 15.

While not in the market right now, I am thinking ahead to a rotary table
and wondering how I am going to align it. A centering indicator is one
option, but it looks a little long for a mill-drill. I might be able to
make it work by mounting it in an R8 collet, bumping in the table, and
then changing back to my ER chuck for normal work. With the mill's
dials locked, (if needed) I could move the table to free up space under
the spindle, change, and then start work with the RT's axis at zero on
the dials.

Is there an easier way? Is there another type of indicator I should
consider?

Bill

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

With respect to dial test indicators, I am struggling with understanding
auto-reverse. It appears to be good, but what is it? I see lots of
mention of not needing to flip a lever; are such indicators obsolete now?
Is there any reason one would want one?

I can't think of a reason.


It might help to start w/ my import's behavior: the dial advances
clockwise from zero regardless of the direction of motion of the point. It
looked weird at first (the dial markings suggest it would do something
else), but I figured it was probably by design, having something to do
with an indicator version of backlash near zero.

I'm not sure why they do this (I have one too) but I don't find it to be an
issue. You can't use both direcitons at the same time anyway...


When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and work
relative to that. I don't bother to move the dial, though it might be
smart to "permanently" offset it so that I'm working at zero vs. 15.

15 is excessive. A preload of a couple of thou should more than suffice.


While not in the market right now, I am thinking ahead to a rotary table
and wondering how I am going to align it. A centering indicator is one
option, but it looks a little long for a mill-drill. I might be able to
make it work by mounting it in an R8 collet, bumping in the table, and
then changing back to my ER chuck for normal work. With the mill's dials
locked, (if needed) I could move the table to free up space under the
spindle, change, and then start work with the RT's axis at zero on the
dials.

Depending on what you're doing, there are a number of ways to setup a rotary
table. I don't think you need a centering indicator though (especially given
the price).

Typically you center the part on the rotary table first. Once that's done,
center the spindle over the rotary table.

Many people make tooling plates for their rotary tables so they can cut into
the table (only slightly) if required to mill a complicated profile. If you
make a tooling plate, you can place a dowel hole in the center and then use
a dowel pin to center the rotary table to the spindle. The part too, if you
can accomodate a dowel pin hole in it.


Is there an easier way? Is there another type of indicator I should
consider?

I'd recommend getting one that will reverse without flipping a lever. Levers
are annoying.

Regards,

Robin

Robin,

When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and work
relative to that. I don't bother to move the dial, though it might be
smart to "permanently" offset it so that I'm working at zero vs. 15.


15 is excessive. A preload of a couple of thou should more than suffice.

15 is _convenient_



Many people make tooling plates for their rotary tables so they can cut into
the table (only slightly) if required to mill a complicated profile. If you
make a tooling plate, you can place a dowel hole in the center and then use
a dowel pin to center the rotary table to the spindle. The part too, if you
can accomodate a dowel pin hole in it.

Got it. Thanks for your reply!

Bill

"Bill Schwab" wrote in message
k.net...
Robin,

When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and
work relative to that. I don't bother to move the dial, though it might
be smart to "permanently" offset it so that I'm working at zero vs. 15.


15 is excessive. A preload of a couple of thou should more than suffice.

15 is _convenient_

Perhaps I'm not reading you correctly, but the indicator's dial can be
rotated to any convenient spot.

Regards,

Robin

"Robin S." wrote in message
.. .

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

With respect to dial test indicators, I am struggling with understanding
auto-reverse. It appears to be good, but what is it? I see lots of
mention of not needing to flip a lever; are such indicators obsolete
now?
Is there any reason one would want one?

I'm of the opinion that what they mean is that the indicator will function
in either direction without moving a lever. A Starrett Last Word is an
example of an indicator that must be manually reversed. A B&S BesTest is
an example of one that will function in either direction without moving a
lever. I own both and highly recommend the B&S over the LastWord. The
mechanics of both designs have little in common with one another and the
Last Word tends to give poor readings.


I can't think of a reason.


It might help to start w/ my import's behavior: the dial advances
clockwise from zero regardless of the direction of motion of the point.
It
looked weird at first (the dial markings suggest it would do something
else), but I figured it was probably by design, having something to do
with an indicator version of backlash near zero.

I'm not sure why they do this (I have one too) but I don't find it to be
an
issue. You can't use both direcitons at the same time anyway...

All too true----you can't use it in both directions at the same time, but
it's a nice feature that you can use either one without making any changes
(flipping a lever). A good example might be if you had a round object on a
rotary table and wanted to dial both the bore of the table, then the OD of a
part, in succession. All you need to do is move from one location to the
other. The indicator is ready to read in either situation. That would not
be true of an indicator with a lever, and there could be times when moving
the lever might not be convenient. Working in a deep hole might be a good
example of such a situation.



When indicating a vise or a part, I use the cross travel to make contact
with the point and then continue moving to get a non-zero reading and
work
relative to that. I don't bother to move the dial, though it might be
smart to "permanently" offset it so that I'm working at zero vs. 15.

15 is excessive. A preload of a couple of thou should more than suffice.

The amount certainly isn't critical, so long as one can read the amount of
deflection from one end of the object being dialed to the other end.

When sweeping the surface of a table to square a spindle, it's obviously to
advantage to have as little preload as possible so the tip can glide over
the T slots, or other examples of a similar nature, but otherwise it makes
little difference. Remember, you are not really measuring with a DTI
under setup conditions, but looking for anomalies so they can be eliminated
or minimized. The indicator, in use, behaves as a comparator. It's not
really "measuring", although it does display in increments that translate
into measurements.
..


While not in the market right now, I am thinking ahead to a rotary table
and wondering how I am going to align it. A centering indicator is one
option, but it looks a little long for a mill-drill. I might be able to
make it work by mounting it in an R8 collet, bumping in the table, and
then changing back to my ER chuck for normal work. With the mill's
dials
locked, (if needed) I could move the table to free up space under the
spindle, change, and then start work with the RT's axis at zero on the
dials.

Depending on what you're doing, there are a number of ways to setup a
rotary
table. I don't think you need a centering indicator though (especially
given
the price).

Any common DTI will suffice. It should be held in the spindle of the
machine and inserted into the bore of the rotary table. Do not rotate the
table, that won't tell you anything aside from the eccentricity of the
bushing in the table (which should be 0). The spindle of the machine is
rotated with the indicator in intimate contact with the bushing. The table
and saddle are then adjusted until you get an equal reading on all four
sides, or a constant reading, regardless of what it is. At that point,
you should mark your table and saddle (wax pencil) so you have a reference
point at which your dials will read 0-0, and each of them should be set such
that you know which direction has eliminated backlash. My style is to
always set the dials so they are reading in the right hand direction. That
way you never have to remember which way you set the backlash. Only under
very unusual circumstances do I set the backlash differently.


Typically you center the part on the rotary table first. Once that's done,
center the spindle over the rotary table.

While that might work, once a part is set on a rotary table, the center hole
is usually covered, so you can't use it to set up the table. It's
typically best to set up the table as above, then dial in your part. It's
generally more important to know the table is set properly, especially if
you have several parts to machine. Assuming you make a minor mistake in
the setup from a part, the same error is introduced to each and every
succeeding part that is set up. It could spell the difference between a
good part or scrap. Both methods will work, one has the edge.


Many people make tooling plates for their rotary tables so they can cut
into
the table (only slightly) if required to mill a complicated profile. If
you
make a tooling plate, you can place a dowel hole in the center and then
use
a dowel pin to center the rotary table to the spindle. The part too, if
you
can accomodate a dowel pin hole in it.

Yep! Very effective way to make setups on a rotab, especially if you're
stuck with a small table. My plate has random holes drilled and tapped for
hold down clamps, and I don't hesitate to add them as required. The plate
is aluminum, and considered perishable. Considering I have a 12" Bridgeport
table, my plate has a 1" diameter hardened and ground pin for the plate,
which locates from the center hole of the table. Setups can, therefore, be
torn down and re-established without losing concentricity.



Is there an easier way? Is there another type of indicator I should
consider?

I'd recommend getting one that will reverse without flipping a lever.
Levers
are annoying.

I couldn't agree more. I recommend the B&S highly. I've had two of them
for countless years (well over 30) and the only thing that has gone wrong
with either of them is the crystal shrinking.

Harold


Regards,

Robin

In article , Harold and Susan Vordos says...

... Remember, you are not really measuring with a DTI
under setup conditions, but looking for anomalies so they can be eliminated
or minimized. The indicator, in use, behaves as a comparator. It's not
really "measuring", although it does display in increments that translate
into measurements.

The analog in the world of electrical measurements is a "null detector"

The actual linear sensitivity of a last word type indicator varies
a great deal across its range because of the cosine error between the
angle of the point and the surface it's sweeping. But it will be
most sensitive at one spot and if the needle nulls (never moves)
during the measurement, one can be sure the feature and the machine
axis are lined up. The non-linearity of the detector drops out.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

"jim rozen" wrote in message
...
In article , Harold and Susan Vordos says...

... Remember, you are not really measuring with a DTI
under setup conditions, but looking for anomalies so they can be
eliminated
or minimized. The indicator, in use, behaves as a comparator. It's not
really "measuring", although it does display in increments that translate
into measurements.

The analog in the world of electrical measurements is a "null detector"

The actual linear sensitivity of a last word type indicator varies
a great deal across its range because of the cosine error between the
angle of the point and the surface it's sweeping. But it will be
most sensitive at one spot and if the needle nulls (never moves)
during the measurement, one can be sure the feature and the machine
axis are lined up. The non-linearity of the detector drops out.

Jim

While that appears to be true of the B&S indicators I've used, as is often
the case with a Last Word, the lack of movement of the hand is not an
indication of perfect alignment. Once the error falls below a thou, they
often won't display, so you are lulled into a false sense of proper
alignment.

Frankly, the only thing I've found for which my Last Word is acceptable is
for removing taper on grinding machines, or rough setups with a 4 jaw.
I'm shocked that Starrett is still producing them, assuming they are.

Harold

In article , Harold and Susan Vordos says...

The actual linear sensitivity of a last word type indicator ...

While that appears to be true of the B&S indicators I've used, as is often
the case with a Last Word, the lack of movement of the hand is not an
indication of perfect alignment. Once the error falls below a thou, they
often won't display, so you are lulled into a false sense of proper
alignment.

That's why I said "last word type" there - I am very well aware
of your feelings about starrett's offerings in those instruments.

g

And in fact I did purchase a BestTest indicator at work - and
was suitably impressed by it's quality in comparison.

Still, I wonder if maybe your starrett instrument is sticky or
dirty - mine will read reliably inside two of the thou lines
on the dial.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

On 10 Dec 2005 08:43:02 -0800, jim rozen
scribed:

In article , Harold and Susan Vordos says...

... Remember, you are not really measuring with a DTI
under setup conditions, but looking for anomalies so they can be eliminated
or minimized. The indicator, in use, behaves as a comparator. It's not
really "measuring", although it does display in increments that translate
into measurements.

The analog in the world of electrical measurements is a "null detector"

The actual linear sensitivity of a last word type indicator varies
a great deal across its range because of the cosine error between the
angle of the point and the surface it's sweeping. But it will be
most sensitive at one spot and if the needle nulls (never moves)
during the measurement, one can be sure the feature and the machine
axis are lined up. The non-linearity of the detector drops out.

Jim

Yes, Jim. You are right. There are very many cosine errors to be
worried about using a dial lever gage (DTI). Some can be reckoned with
by using a pear shaped contact point that may null out some of the
angular problems. But only through a very, very small range .

Others can be dealt with by using the instrument in a parallel way...
Ie; the more you put the point out of parallel, the more error you get
on broader measurements. Tip here is only use them for very small,
comparative measurements, not as a measuring tool on the bigger
ranges. Keep it close to home.

As Jim says, the indicator is most linear in it's first few thou of
travel, (past null) and if you need more than that, better to get a
good dial gage that reads in tenths (0.0001). They are linear,
accurate and unfortunately, quite expensive.

Best as always,

Freddie

Harold,

Any common DTI will suffice. It should be held in the spindle of the
machine and inserted into the bore of the rotary table. Do not rotate the
table, that won't tell you anything aside from the eccentricity of the
bushing in the table (which should be 0). The spindle of the machine is
rotated with the indicator in intimate contact with the bushing. The table
and saddle are then adjusted until you get an equal reading on all four
sides, or a constant reading, regardless of what it is. At that point,
you should mark your table and saddle (wax pencil) so you have a reference
point at which your dials will read 0-0, and each of them should be set such
that you know which direction has eliminated backlash. My style is to
always set the dials so they are reading in the right hand direction. That
way you never have to remember which way you set the backlash. Only under
very unusual circumstances do I set the backlash differently.

This reminds of a question that I have been trying to formulate. It
first stood in my way with a plate that I "freed" from a rough cut piece
of metal. The stock was too thin and big to be suitable for my usual
approach to squaring in a vise, so I clamped it on the table (with
plywood underneath of course). I arbitrarily set the dials to zero, and
settled for allowing half the nominal size of the endmill to establish
the dimensions. That was more than good enough, because only relative
hole positions were important on the part.

For the right and front edges, it might have been (or seemed??) easier
to switch to what you have termed left hand backlash. Is there a
correct way to do that? As it was, for each cut that went against
backlash, I backed up, overshot, and then stopped at the new position.

I suppose the same problem would arise if one wanted right hand backlash
but somehow needed to edge find on the right side of something. So
far, the best I know to do is backup, overshoot, and re-approach in the
backlash-safe direction. For an RT, I assume this will be necessary on
one side in each direction??

Please feel free to answer with something along the lines of "keep
trying to formulate that question".

You made reference to getting by with small table. How does one know
what is small relative to a given part size?

Thanks!

Bill

a
"Bill Schwab" wrote in message
nk.net...
Harold,
snip---

I arbitrarily set the dials to zero, and
settled for allowing half the nominal size of the endmill to establish
the dimensions. That was more than good enough, because only relative
hole positions were important on the part.

For the right and front edges, it might have been (or seemed??) easier
to switch to what you have termed left hand backlash. Is there a
correct way to do that? As it was, for each cut that went against
backlash, I backed up, overshot, and then stopped at the new position.

Unless there's a reason you need the dial to be direct reading from both
sides, all you do is reverse feed when you get to the end. Backlash, in
this instance, isn't an issue. Once you've measured the piece after taking
a cut, you have an idea how much must come off to take the part to size, so
you can then read the dial backwards. What that means is that you don't
expect a dial to give you readings on each end of a part. If, by chance,
you know exaclty how much backlash the machine has at a given point, you
could calculate that into your reading, but it's not done routinely, if at
all. If that isn't what you want to do, then how you detailed the cut is
how it is done. You always go past the target mark, then feed back to it
turning the handle in the direction you've set backlash. Using a DRO
eliminates the worry of backlash as far as dimensions are concerned, but I
wasn't afforded that luxury when I was trained. There was no such thing.
I learned to machine without them, and still work that way.

If you're cutting a window, and you need to know where the cutter stops on
four sides, what I do is measure and ignore backlash. Make a little sketch
of a window, and write the dial locations on each side---and don't worry
about backlash on the third and fourth sides. By measuring, you know where
you are, and can turn directly to your finished size. That's not a big
deal for one piece, but if you have multiple pieces to machine, once you've
marked the dials, you can cut windows in short order. With a final pass,
maybe a couple thou, climb milling, you can go into corners and out without
leaving a trace of undercut.


I suppose the same problem would arise if one wanted right hand backlash
but somehow needed to edge find on the right side of something. So
far, the best I know to do is backup, overshoot, and re-approach in the
backlash-safe direction. For an RT, I assume this will be necessary on
one side in each direction??

Depends on how you apply the table. I think you'll find that there are
times when you may set your backlash in one direction (as I detailed, fore
example) and be able to run your parts without worrying about changing
anything. One thing to remember is if you screw with the dials on the
machine after you've located the centerline of the table as it relates to
the spindle, you have lost orientation completely, so you have to start
over. I highly recommend you learn to deal with backlash as you outlined
it, just by overshooting it than turning back. If you establish that habit,
it's much easier to work, and you eliminate, to a large degree, the
potential for making scrap. Don't be too discouraged if at first you
screw up a little. Most of us do.


Please feel free to answer with something along the lines of "keep
trying to formulate that question".

Not necessary. In my opinion, that was a good question. The answer is
simple. Those of us that work freely with backlash do so because of
extensive experience. Some achieve the same thing instantly, while others
will struggle for some time before it becomes routine. It's just one more
of the things that separate machinists from the guy on the street. Like
any trade, these are the types of things we master in the process of
becoming journeymen.


You made reference to getting by with small table. How does one know
what is small relative to a given part size?

One simple rule is if you're cutting the exterior of a large item and the
table is smaller (envision holding the part by holes located within the
part, such as holes in a sprocket, for example). The mechanical advantage
can get out of balance in a hurry, and it becomes difficult to turn the
table while conventional milling, and down right dangerous if you try to
climb. Climbing on a rotab isn't a good idea anyway, but you can often do
so to good advantage by setting drag with the table lock(s).

My rule of thumb for a rotab is real simple. Anything less than a 12" table
isn't a good idea. I'm likely to get a lot of arguments with that
statement, but if you've ever had to do any serious work on a rotab, you
quickly come to terms with how damned hard it can be to make a setup. It's
often almost impossible to find a place for clamps, for one. The larger
the table, in most cases, the better. Keep in mind you have to handle them
to get them on the machine----so anything larger than a 12" becomes really
difficult. If the table is a compound, it's likely already impossible.
If, by chance, you have to use the table on end, size then works against
you, too. There's no perfect answer unless you happen to own more than
one, each a different size. Bottom line here is each guy feels he can do
everything he needs to do with the size at his disposal. I'd recommend
nothing smaller than a 6" table, but I'd hate to be tied down to one that
small. Maybe the best thing to do is visualize the projects you might
be interested in running, then see how it works out with clamps. The
typical rotab has slots @ 90 degrees, so you do have the added advantage of
a second set of slots as opposed to the typical mill table.

Thanks!

Bill
Better check what I said before you thank me, Bill. I have my own way of
working, and it isn't necessarily the same way as others. It works for
me, but it might not for you. At any rate, let us know what you decide.
Your opinion might be valuable to others in a similar circumstance.

Harold

Harold,

Unless there's a reason you need the dial to be direct reading from both
sides, all you do is reverse feed when you get to the end. Backlash, in
this instance, isn't an issue. Once you've measured the piece after taking
a cut, you have an idea how much must come off to take the part to size, so
you can then read the dial backwards. What that means is that you don't
expect a dial to give you readings on each end of a part.

Let me try to paraphrase. You are saying that I can count off the
desired size plus tool radius plus some wiggle room, take a cut,
measure, and then back up based on relative dial readings. Fair?


If, by chance,
you know exaclty how much backlash the machine has at a given point, you
could calculate that into your reading, but it's not done routinely, if at
all.

I wouldn't expect that to work - that by no means implies that it would
not work.


If that isn't what you want to do, then how you detailed the cut is
how it is done. You always go past the target mark, then feed back to it
turning the handle in the direction you've set backlash. Using a DRO
eliminates the worry of backlash as far as dimensions are concerned, but I
wasn't afforded that luxury when I was trained. There was no such thing.
I learned to machine without them, and still work that way.

So far, I have found that I can see +/- 0.1 inch, and the dials do the
rest. It is true that I sometimes have to switch from a 0.5 inch
endmill to a 3/32 drill bit in order to be confident of the center of
the cutter, but that's really not that hard to do (have I said anything
good about ER collets today?g) and beats adding to my scrap bin.

For those not convinced by the "I can get by w/o it" argument, you might
better relate to my desire to get other tools, an RT, boring head and
bars, etc., not to mention more woodworking tools.

Another thing that bothers me about a DRO: they can skip. It sounds
like something that will start happening just about the time I grow to
depend on it. Living in FL, lightning is a concern. A direct strike
could knock out my motor, but a DRO would be much more likely to get fried.

There is also the problem of moving raw materials (mostly wood).
Renting trucks is a pain, not to mention that I do not like to drive
vehicles that do not belong to me. A pickup is probably in order. I
like my car too much to work on it myself, but a bomb of a pickup will
give me freedom to dabble in simple repairs (all together now - but NOT
THE BRAKES!!!!g).

Speaking of pickups, recommendations for make/model/year are welcome.
Gas mileage is not really a concern, because I will not drive it much.
Handling plywood will be a common task. Total cost to keep it reliable
and safe is a factor, and being friendly to an inexperienced shade tree
mechanic (with support from experienced friends) is a big plus. As
shocking as the concept might be in FL, AC is negotiable, and would
likely not be repaired. The one in my car gets what it need$ =:0

Sorry for the digression.


If you're cutting a window, and you need to know where the cutter stops on
four sides, what I do is measure and ignore backlash. Make a little sketch
of a window, and write the dial locations on each side---and don't worry
about backlash on the third and fourth sides. By measuring, you know where
you are, and can turn directly to your finished size. That's not a big
deal for one piece, but if you have multiple pieces to machine, once you've
marked the dials, you can cut windows in short order. With a final pass,
maybe a couple thou, climb milling, you can go into corners and out without
leaving a trace of undercut.

I _think_ I understand. On the sides backlash-safe sides, how do you
account for the endmill radius?



Depends on how you apply the table. I think you'll find that there are
times when you may set your backlash in one direction (as I detailed, fore
example) and be able to run your parts without worrying about changing
anything. One thing to remember is if you screw with the dials on the
machine after you've located the centerline of the table as it relates to
the spindle, you have lost orientation completely, so you have to start
over.

Understood and agreed.



Don't be too discouraged if at first you
screw up a little. Most of us do.

It hasn't discouraged me so far



One simple rule is if you're cutting the exterior of a large item and the
table is smaller (envision holding the part by holes located within the
part, such as holes in a sprocket, for example). The mechanical advantage
can get out of balance in a hurry, and it becomes difficult to turn the
table while conventional milling, and down right dangerous if you try to
climb. Climbing on a rotab isn't a good idea anyway, but you can often do
so to good advantage by setting drag with the table lock(s).

Thanks for the warning.


My rule of thumb for a rotab is real simple. Anything less than a 12" table
isn't a good idea. I'm likely to get a lot of arguments with that
statement, but if you've ever had to do any serious work on a rotab, you
quickly come to terms with how damned hard it can be to make a setup. It's
often almost impossible to find a place for clamps, for one. The larger
the table, in most cases, the better.

I suspect that most things I would do would end up being mounted with
holes inside the part - all the more likely if I buy a smallish table.


Keep in mind you have to handle them
to get them on the machine----so anything larger than a 12" becomes really
difficult. If the table is a compound, it's likely already impossible.

My shop crane would do it, but the point is well taken. OTOH, I doubt
anything bigger would fit on my 31.


If, by chance, you have to use the table on end, size then works against
you, too. There's no perfect answer unless you happen to own more than
one, each a different size. Bottom line here is each guy feels he can do
everything he needs to do with the size at his disposal. I'd recommend
nothing smaller than a 6" table, but I'd hate to be tied down to one that
small. Maybe the best thing to do is visualize the projects you might
be interested in running, then see how it works out with clamps. The
typical rotab has slots @ 90 degrees, so you do have the added advantage of
a second set of slots as opposed to the typical mill table.

Maybe the answer is to get a small horiz/vert table and then see if I
find need for anything bigger. There is certainly no hurry. For now, I
can do what I have in mind with an extra setup or two and a rounding
endmill.




Better check what I said before you thank me, Bill. I have my own way of
working, and it isn't necessarily the same way as others. It works for
me, but it might not for you. At any rate, let us know what you decide.
Your opinion might be valuable to others in a similar circumstance.

I am grateful for your thoughtful reply independent of whether or not I
agree with every part of it. As it happens, I find that I end up
agreeing with most of what you say.

If I were to look for an area to disagree with you, it would probably be
over the validity of mill-drill machines. You are correct to caution
people about the limitations, but the machine is serving me well. If,
as some here have predicted, I end up with a monster knee mill, the $900
for the mill drill itself will have been well spent.

Thanks!!!

Bill

The autoreversing DTI have a heart shaped cam that the tip rides against so
that any motion from the center will push the cam back and thus cause a
movement of the needle.
These are very nice when you are just indicating as you don't have to do
any thinking about what directions are happening with a particular setup.

--
Why do penguins walk so far to get to their nesting grounds?