OK, one for the practical machinists - no, I am not going to buy some
special tool costing zillions to get round this problem...

Turned a MT2 taper on the lathe, 0.5mm oversize. Used the topslide on
the lathe, set it up with a dial indicator for (virtually) zero
deflection along the length of a reference MT2 taper - which, BTW, was
pretty worn/crappy, it was a MT1 to MT2 adapter that had a hard life -
I used a ruler, sighted it lengthwise to get the "best" one for the
setup....

(An aside - the complication is that the school exercise to to grind a
MT3, I changed it to MT2 so it would fit my lathe at home - end result
will be a centre drill holder..)

So, booked the cylindrical grinder, got the tool set for it, the
instructor showed me how to set it, using the aforementioned MT2 taper
I had turned. Took a while, but eventually, using a finger gauge,
measuring the grinding side (important that, as I soon realised) set
it up to AFAIK bloody very close to PERFECT.

Ground the thing, it was out by ?? degrees. Blast, Oh Dear, - and
other appropriate words.

OK, obviously my lathe turned taper was out. Tried to set up the
grinder with the MT2 adapter I had used earlier. Had to move the
tailstock on the grinder as it was longer than my work piece. Set it
up, ignoring the bumps and variations on a worn adapter.

Feeling pretty good about how smart I was , reset the tailstock to the
workpiece. Immediately realised I had lost registration by moving the
tailpiece.

I then ran out of time, will do night class next week to sort it out.

So, good people - how do I set it up to do an MT2 taper? - there is a
degree scale at the end of the grinder bed (where the adjuster is) but
its not accurate enuff to set by, and besides, its an old grinder so
its probably out. By trigonometry - get the degree taper, construct a
triangle, work out offset by this - mm, yes - but how to transfer it
to the end of the bed. Besides it would need very accurate marking out
and measuring, and as there is no gauge on the horizontal travel of
the bed....

There is a dial gauge attached to the adjuster end, but stuffed if I
know how to use it for this setup.

Arrrgh! - help!!!

Andrew VK3BFA.

wrote:
OK, one for the practical machinists - no, I am not going to buy some
special tool costing zillions to get round this problem...

Turned a MT2 taper on the lathe, 0.5mm oversize. Used the topslide on
the lathe, set it up with a dial indicator for (virtually) zero
deflection along the length of a reference MT2 taper - which, BTW, was
pretty worn/crappy, it was a MT1 to MT2 adapter that had a hard life -
I used a ruler, sighted it lengthwise to get the "best" one for the
setup....

(An aside - the complication is that the school exercise to to grind a
MT3, I changed it to MT2 so it would fit my lathe at home - end result
will be a centre drill holder..)

So, booked the cylindrical grinder, got the tool set for it, the
instructor showed me how to set it, using the aforementioned MT2 taper
I had turned. Took a while, but eventually, using a finger gauge,
measuring the grinding side (important that, as I soon realised) set
it up to AFAIK bloody very close to PERFECT.

Ground the thing, it was out by ?? degrees. Blast, Oh Dear, - and
other appropriate words.

OK, obviously my lathe turned taper was out. Tried to set up the
grinder with the MT2 adapter I had used earlier. Had to move the
tailstock on the grinder as it was longer than my work piece. Set it
up, ignoring the bumps and variations on a worn adapter.

Feeling pretty good about how smart I was , reset the tailstock to the
workpiece. Immediately realised I had lost registration by moving the
tailpiece.

I then ran out of time, will do night class next week to sort it out.

So, good people - how do I set it up to do an MT2 taper? - there is a
degree scale at the end of the grinder bed (where the adjuster is) but
its not accurate enuff to set by, and besides, its an old grinder so
its probably out. By trigonometry - get the degree taper, construct a
triangle, work out offset by this - mm, yes - but how to transfer it
to the end of the bed. Besides it would need very accurate marking out
and measuring, and as there is no gauge on the horizontal travel of
the bed....

There is a dial gauge attached to the adjuster end, but stuffed if I
know how to use it for this setup.

Arrrgh! - help!!!

Andrew VK3BFA.




How accurate do you want to be, and how are you measuring the taper on
the ground part? The dial gauge is for reference purposes only, unless
you know the center distance from the table pivot to the dial gauge.

You cannot grind it right the first time on an unfamiliar grinder. (you
can get close)

If you know the center distance from the pivot point to the gauge, (in
the manual), you grind a sample, (same length as your part, so you don't
have to move the tailstock) as straight as you can. Then you can trig
out the amount to move the tailstock by using the dial gauge.


Otherwise, grind sample straight, then shift table taper about .100 on
dial gauge and grind sample again until full clean up. Measure taper on
sample, and you can calculate how much more you need to move dial gauge
to get your taper.

Record your measured taper angle after the .100 move and keep for
reference. You can back calculate the center distance of the grinder
with it.

Always move a little less than you need when creeping up on it, as
it's easier to take more off the small end than the big end.

Don't forget to ALWAYS back off dial gauge and move back to where you
want to be, to account for any backlash.

Use a good high pressure grease in the centers.


See he

http://www.tools-n-gizmos.com/specs/Tapers.html


I used to grind gages at a gage shop, and used to be able to grind a
taper accurate to .000050 over 10 inches. It was a VERY good manual
grinder.

--
Steve Walker
(remove wallet to reply)

On 2008-10-29, wrote:
OK, one for the practical machinists - no, I am not going to buy some
special tool costing zillions to get round this problem...

[ ... ]

So, good people - how do I set it up to do an MT2 taper? - there is a
degree scale at the end of the grinder bed (where the adjuster is) but
its not accurate enuff to set by, and besides, its an old grinder so
its probably out. By trigonometry - get the degree taper, construct a
triangle, work out offset by this - mm, yes - but how to transfer it
to the end of the bed. Besides it would need very accurate marking out
and measuring, and as there is no gauge on the horizontal travel of
the bed....

Do you know about the sine bar? A piece of steel, typically
about 5" long, ground to a very flat surface on top. On the bottom are
two cylinders bolted in -- *precisely* 5.0000" apart, and precisely the
same diameter.

Calculate the height of a stack of gauge blocks needed to get
one end of the sine bar jacked up the right distance to get the desired
angle. Normally, you look up the sine of the angle needed (hence the
name of the sine bar), but looking up Morse tapers, you will find the
tapers specified in inches per inch or inches per foot. Divide that by
two, and convert that to the inches needed over a 5" length. With good
gauge blocks, this will give you about as accurate an angle as you will
need. Look up the taper in _Machinery's Handbook_ -- or some other
reference source.

How you use this to set this up the cylindrical grinder depends
on what kind of reference surface you have to work with. I've never had
access to one to try. But also -- be very careful about the gauge
blocks and the sine bar around any kind of grinder. It is very easy to
damage either with the grit which is all around any grinder.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

wrote in message
...
snip---

Arrrgh! - help!!!

Andrew VK3BFA.


Read what DoN said, and work accordingly. One does not set angles on a
grinder using the calibrations provided on the machine. They are for
reference only, considering they are accurate only at the specified length,
and then only as good as the degree of precision in which the headstock and
tailstock are located. Grinders are meant to be adjusted for each and every
operation. Do not trust any of the markings.

The typical cylindrical (or universal) grinder pivots on the center of the
table. It is common practice to use a dial indicator (a DTI works
adequately) to set taper, be it a straight part or a tapered part. One
takes a light grinding cut to determine the status of the taper, then
adjusts accordingly. Considering the length of the part determines the
effect of offsetting the table, there is no hard, fast rule. Adjust the
table a given amount, determine the effect, then adjust accordingly.
Setting taper may require more than a couple attempts----and if you expect
to grind more than one piece, length is often critical, as is the size of
the center in the part.

Do *not* trust setting the angle by comparing to other devices. Unless you
are dead on center, and the part is perfect, you will introduce error that
will not be in your best interest. Use a sine bar or plate to inspect the
grind, adjusting accordingly. Insure that when you inspect the grind that
it is placed at a perfect right angle on the plate or bar.

Harold

On Oct 30, 4:09 pm, "Harold and Susan Vordos" wrote:
wrote in message

...
snip---



Arrrgh! - help!!!

Andrew VK3BFA.

Read what DoN said, and work accordingly. One does not set angles on a
grinder using the calibrations provided on the machine. They are for
reference only, considering they are accurate only at the specified length,
and then only as good as the degree of precision in which the headstock and
tailstock are located. Grinders are meant to be adjusted for each and every
operation. Do not trust any of the markings.

The typical cylindrical (or universal) grinder pivots on the center of the
table. It is common practice to use a dial indicator (a DTI works
adequately) to set taper, be it a straight part or a tapered part. One
takes a light grinding cut to determine the status of the taper, then
adjusts accordingly. Considering the length of the part determines the
effect of offsetting the table, there is no hard, fast rule. Adjust the
table a given amount, determine the effect, then adjust accordingly.
Setting taper may require more than a couple attempts----and if you expect
to grind more than one piece, length is often critical, as is the size of
the center in the part.

Do *not* trust setting the angle by comparing to other devices. Unless you
are dead on center, and the part is perfect, you will introduce error that
will not be in your best interest. Use a sine bar or plate to inspect the
grind, adjusting accordingly. Insure that when you inspect the grind that
it is placed at a perfect right angle on the plate or bar.

Harold

Thank you Steve, Don, and Harold. The progressive grind then measure
approach seems logical, and point noted re not setting up to a
reference taper. The Sine Bar - its a word at the moment, heard it,
but no idea how to use one. (But will find out)

Accuracy of taper to Don) - accurate enuff to be a good, non slip fit
in the socket. Its out to blazes now as I can wobble it in the socket
- when I get close, will blue it and then see how close it is. Don't
know how much I have to play with after the initial abortive grind,
the angle is greater than required so MIGHT be able to do it - may
have to start over again (bugger!)

Harold - measuring after each cut - can I leave the job on the
machine, use a micrometer to measure the major and minor diameters? I
note in the reference tables (thanks Steve) that the drawing shows a
fixed length, measured at each end. This does not agree with the ones
I have seen, some are longer than others. I would imagine (???) that
the big diameter
so long as it occurs somewhere along its length, and the small
diameter is the size at the length designated in the tables, then its
ok. I know mine is pretty short, just a few mm projecting out of the
socket (when its cut, of course - not at the moment)

So. Once again, thanks to the members here. The learning curve is
flattening out a little, but still has the occasional deviation to
vertical!

Andrew VK3BFA.

wrote in message
...
snip----

Harold - measuring after each cut - can I leave the job on the
machine, use a micrometer to measure the major and minor diameters?

Yes, you can, but the level of precision will be drastically limited.
Grinding is generally considered to be extremely precise---in many cases
working to millionths. If you can not remove and replace the object being
ground, you will be subject to a serious amount of setup time-----in dialing
in the work piece. It is for that reason that precision grinding is best
accomplished between centers. Instant removal and replacement are a
desired feature, which that allows. Best yet is that working between
centers offers a constant adjustment of error, as in when stress causes your
work piece to move about freely, and be constantly corrected.

If you are not now grinding between centers, you would gain a great deal by
starting over and doing so. It is not beyond possibility.


I note in the reference tables (thanks Steve) that the drawing shows a
fixed length, measured at each end. This does not agree with the ones
I have seen, some are longer than others. I would imagine (???) that
the big diameter
so long as it occurs somewhere along its length, and the small
diameter is the size at the length designated in the tables, then its
ok. I know mine is pretty short, just a few mm projecting out of the
socket (when its cut, of course - not at the moment)

Lets re-visit the idea of using a sine plate or bar. The objective here
is to set the proper angle. By using a sine type tool, the degree of error
can be limited to less than a tenth. Length would play only a miniscule
role, although the longer the taper you grind, the greater will be your
ability to detect error. Once you have established the proper taper, you
can then size one end or the other, with length being a non-issue.


So. Once again, thanks to the members here. The learning curve is
flattening out a little, but still has the occasional deviation to
vertical!

Andrew VK3BFA.

I strongly suggest you look at grinding in a totally different light than
you do turning on a lathe. Grinding is more art than anything----and
requires a light touch and good sense. Few machinists make a good
grinder----most are too crude and heavy handed. Treat your grinder with
due respect, never over tightening fasteners, and NEVER touching the
machine, aside from the dials, when it is working. The slightest defection
of the table when it is working will readily show in the grind.

Remember-----precision grinding is an art-----not always mastered by many.

Harold

On Nov 2, 6:26 am, "Harold and Susan Vordos" wrote:
wrote in message

...
snip----

I strongly suggest you look at grinding in a totally different light than
you do turning on a lathe. Grinding is more art than anything----and
requires a light touch and good sense. Few machinists make a good
grinder----most are too crude and heavy handed. Treat your grinder with
due respect, never over tightening fasteners, and NEVER touching the
machine, aside from the dials, when it is working. The slightest defection
of the table when it is working will readily show in the grind.

Remember-----precision grinding is an art-----not always mastered by many.

Harold

Thanks Harold - yes, the job can be removed from the machine, it is
ground between centres - I have set it up properly re the driving dog,
was instructed on that. the tailstock end (for want of a better word)
is lever actuated. Was worried about losing registration. Point noted
re using micrometers to measure. Will look up sine bar in the text
book - I thinks its a 4th year subject (changing light bulbs was year
2!)

The thing is, I will probably never go near a grinder again, just want
to do it for the sheer joy of learning something new!

Andrew VK3BFA.

wrote in message
...
On Nov 2, 6:26 am, "Harold and Susan Vordos" wrote:
wrote in message

...
snip----

I strongly suggest you look at grinding in a totally different light than
you do turning on a lathe. Grinding is more art than anything----and
requires a light touch and good sense. Few machinists make a good
grinder----most are too crude and heavy handed. Treat your grinder with
due respect, never over tightening fasteners, and NEVER touching the
machine, aside from the dials, when it is working. The slightest
defection
of the table when it is working will readily show in the grind.

Remember-----precision grinding is an art-----not always mastered by
many.

Harold

Thanks Harold - yes, the job can be removed from the machine, it is
ground between centres - I have set it up properly re the driving dog,
was instructed on that. the tailstock end (for want of a better word)
is lever actuated. Was worried about losing registration.

That is typical of grinding machines. While everything looks rather
unstable, it isn't.

Grinders achieve their precision from the operator----not from the machine.
If one does not know to make the setup properly, poor results can be
expected.

Grinding forces are relatively low, assuming you don't do stupid things.
Tailstock pressure is always spring loaded, so it is constant. You may
note that there is a pressure adjustment on the tailstock.

You should be able to remove the part, inspect it, and return it to the
machine without any signs of it having been removed. If you can't,
something is woefully wrong with the machine. We used to remove parts
routinely, checking them for size with either a micrometer or a Sheffield
Shadow Graph. There was never a concern about replacing the part in the
machine.

I mentioned that length and depth of the centers can be of concern. For a
one-off, where you use the part to establish the proper taper (or lack
thereof), it's a non-issue, but if the grinder is a universal and the
headstock is not perfectly aligned, while you can still achieve the desired
results by making adjustments with the table, the tailstock is not in dead
alignment, so any variations in length can create error in taper.

Of all the operations I experienced in my years in the shop, I found
grinding to be the most satisfying. Were I to pursue my machining career
over again, I would specialize in precision grinding.

Harold

On 2008-11-01, wrote:
On Oct 30, 4:09 pm, "Harold and Susan Vordos" wrote:
wrote in message

...

[ ... ]

Accuracy of taper to Don) - accurate enuff to be a good, non slip fit
in the socket. Its out to blazes now as I can wobble it in the socket
- when I get close, will blue it and then see how close it is.

Ideally -- you want a pair of gauges -- a female (for checking
the male which you are trying to make, and a male (for checking whether
your socket is truly correct. The gauges are hardened and ground to
final size.

Don't
know how much I have to play with after the initial abortive grind,
the angle is greater than required so MIGHT be able to do it - may
have to start over again (bugger!)

Harold - measuring after each cut - can I leave the job on the
machine, use a micrometer to measure the major and minor diameters? I
note in the reference tables (thanks Steve) that the drawing shows a
fixed length, measured at each end. This does not agree with the ones
I have seen, some are longer than others. I would imagine (???) that
the big diameter
so long as it occurs somewhere along its length, and the small
diameter is the size at the length designated in the tables, then its
ok. I know mine is pretty short, just a few mm projecting out of the
socket (when its cut, of course - not at the moment)

Note that both of these are often longer than the standard, and
the female may have steps to half diameter for the extend portions, and
the male gauge (and some dead centers) may have a groove marking the
point at which the big end occurs.

I've been collecting the gauges from eBay sales over the years.
So far I have MT-1, MT-2, MT-3 and the female half of MT-4. I still
want MT-0 (both), MT-5 (both) and the male half of MT-4 to have a full
set to match the set of Morse Taper finish reamers which I have (came
1-5 in a wooden box, and I've added my already owned MT-0 reamer.

Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 2008-11-02, wrote:

[ ... ]

Thanks Harold - yes, the job can be removed from the machine, it is
ground between centres - I have set it up properly re the driving dog,
was instructed on that. the tailstock end (for want of a better word)
is lever actuated. Was worried about losing registration. Point noted
re using micrometers to measure. Will look up sine bar in the text
book - I thinks its a 4th year subject (changing light bulbs was year
2!)

Hmm ... I checked my favorite reference, and while sine bars are
mentioned several places in the indexes, the page which actually shows a
sine bar in use is page 502 of the two-volume edition of _Machine Shop
Practice_ by K. H. Moltrecht. Oh yes -- an a serious 20-inch one on Page
503 -- doing exactly what you want to do -- measuring a taper.

Both examples are using an electronic gauge head and display to
show very tiny variations (micro-inches) from the desired angle -- but
you could probably do it well enough for your purposes with a
tenths-reading indicator.

Volume 1, page 284, shows a way to measure a taper using gauge
blocks, rolls (steel rods of precise diameter), and a micrometer.

You may find the books in your local library (ISBN 0-8311-1126-7
and ISBN 0-8311-1132-1). I got my set from MSC when they were being
offered on sale.

Did you take trig? Wondered what use you would ever get from
it? The length between the rolls is the hypotenuse of a right triangle,
and is the first known -- usually 5", though I have a 2.5" one, and the
book shows a 20" one in use. The height of the stack of gauge blocks
under one end is the second known. Since it is a right triangle, that
is a third known (two lengths and an angle) and from that you can use
trig functions (the sine in this case) to calculate the angle you get
from a given height of gauge blocks -- or you can reverse the
calculation to determine the required height to get the desired angle.
The only reason for the cylindrical sections at the ends is so the
length does not change as the end is lifted.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---