I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney

Robert Swinney wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney

Most of the guys I know, me included, would just buy a reamer.

For setting the slide to a male taper, mount a dial indicator on the
slide and adjust until you see no movement indicated when you traverse
the lenth of the "master". I suppose a test bar between centers and two
indicators (one to follow along the test bar and the other to measure
the travel of the slide accuratly) could be made to work. Measure the
given taper per inch in an accurately measured inch of travel.
Cumbersome, but workable without a master to work fron.

That does not even start to deal with the amount that the boring bar
has to hang out of the tool holder to reach the bottom of the taper
socket. It would not surprise me to find that the bar is flexing quite a
bit in the hole. That's going to cause its own set of issues.

Have you considered making a reamer?

Cheers
Trevor Jones

Robert Swinney wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney

Are you sure that the taper you are measuring against is running true?
A dial indicator against a true running shaft and some simple math will
get you the taper per inch that will be read on the dial indicator.
Remember that the dial will read half the amount of taper per inch.


John

"Robert Swinney" wrote in message
. ..
I've been practicing boring a MT #1 with the compound on my Sherline
lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and
setting
it for constant drag on a piece of paper, through the length of taper.
The
material is 12 L 14. Each attempt resulted in a taper alright, and one
that
would lock, but there would be a lot of runout depending on how carefully
I
positioned a test taper in the new socket. It appears the taper (socket)
is
a loose fit on the small end. I expect the taper male to fit solidly in
the
socket and be automatically aligned straight with just a tap from a
plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The
throw
is so short that there is only a very small window of adjustment on a MT
#1.

Bob Swinney

Bob,

Lose the layout blue idea. How in hell that got started is nothing short of
a mystery to me. It's WAY too thick to be of any value, and doesn't tell
you anything, anyway. It balls up prematurely and tells you nothing about
how the metal parts relate to one another. The proper thing to use is
Prussian blue, a very thick oil product that comes in a small tube, much
like a small tube of tooth paste. It's the stuff guys are supposed to use
when scraping. You put it on VERY thin, and look for an interruption in
the pattern when you wring the parts together. When it's properly
applied, only the highs will transfer, very unlike the other stuff that are
often used, with results much like yours.

Another option is to use a sign plate or bar and a surface plate setup to
determine the proper angle, but that demands you be able to set up the parts
perfectly square, otherwise you introduce error. The typical home shop
would be unlikely to be able to make a reasonable setup by that method.

You'll get acceptable results with the Prussian blue, assuming you're
willing to go through the struggle of getting the angle right in the first
place.

Don't make random changes of your compound when setting the angle. Use a
dial indicator against the side and move it a prescribed amount and see what
it does for your fit. You'll quickly come to see how much a thou changes
the angle. Could be a couple of repetitions and you'll have it.

Remember to keep your boring tool at the same height at all times, otherwise
there will be a minor change in the angle.

Harold

On Sat, 11 Mar 2006 22:46:19 -0600, "Robert Swinney"
wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney


Too thin a boring bar and too flexable a lathe. Shrug.. Its actually
better to drill and ream a #1 cause the tooling is by nature gonna be
pretty thin

I was having the same issues with a #2, even when doing it on a
Hardinge HLV-H..the best results were with very high spindle speeds
and tiny cuts towards the end. Stuff was deflecting.

So I scounged a set of #2 roughing and finish reamers.

This works SO much better now

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3

On Sat, 11 Mar 2006 22:46:19 -0600, "Robert Swinney"
wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney

Your standard MT may not hve been aligned well with the spindle, and
I would prefer using a test indicator to feeling drag on a bit of
paper.

I would use a piece of cylindrical stock and set the compound with a
test indicator so it shows the right taper for MT#1 which is .04988"
(diameter) per axial inch. This has worked for me.

Boring tools do spring some, so you need to make finish passes
without increasing the cut until you get a pass that removes no
material. A sharp HSS bit works a lot better than carbide here.

Robert Swinney wrote:
I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.
Yup, here's how I did it, also without a taper attachment.

I had a male taper of known quality that I used as my master. I set
the compound as accurately as I could, and then cut the taper socket.
I then applied Dykem "Hi-Spot blue" dye to the male taper, and put it
in the socket with a light touch and a twisting motion. It will show
a ring of color on the taper you just cut, either that the outer end
or the inner end. That tells you where it is too tight, so you adjust
the compound angle in painfully microscopic increments, and do it again.
When you get close, take off the tool, and rig a Dremel tool or other
similar high-speed spindle to the toolpost. (OK, I cheated here, I
have a toolpost grinder, and I'm not using a Sherline, but a lathe
200 times heavier.) With a small enough grinding wheel in the spindle,
you grind the taper with the lathe spindle running slowly. This gives
a much better surface finish, and the smooth walls will grip the taper
a lot better.

Jon

Harold and Susan Vordos wrote:
Lose the layout blue idea. How in hell that got started is nothing short of
a mystery to me.

Dykem, the famous maker of blue layout dye ALSO
makes "Hi-Spot blue" a prussian blue dye sold specifically for
spotting work. So, the confusion between the same maker's two
blue dyes is pretty easy. And, yes, they are totally different
materials for totally different purposes.

Jon

You've got plenty of good suggestions above.

I'll add that when I did a job like this, I finished by lapping the last 1/2
thousand in. Just take an old drill, cut the tang off, grind a couple
pockets along the side of the drill. Then apply lapping compound, clamp the
drill in the tailstock drill chuck, and run the lathe slow. You'll have a
mirror finish and a perfect taper.

Karl

Robert Swinney wrote:
I've been practicing boring a MT #1 with the compound on my Sherline lathe.
Any suggestionss - please. Is there a better way

Better- I'm not sure. I can give you different. I had a problem checking
the fit on the(close to)B3 end mill holders I made. I cut them by
setting the compound with an indicator using a B3 collet for reference.
Checking the fit was a problem as the collets use a key, and I couldn't
rotate the workpiece in the spindle to get clean rub marks using
HI-Spot. I had some 20 year old Plastigage. I put a piece on opposite
sides of the end mill holder and tightened the drawbar a bit. The
Plastigage deformed, showed how far off the taper was, and where it
needed to be corrected.

http://www.hastingsmfg.com/Tools/plastigage.htm
It is (was) cheap.

I have not heard of anyone using Plastigage in a machining context.
There may be good reasons not to use it, but it worked for me.

Kevin Gallimore

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I agree with Harold. The sine bar method will set the exact taper
angle, then use very fine cuts and Prussian blue to make the final
passes.
Bugs

What brand of Prussian Blue are you using? I haven't found anything
currently that matches it.

Hul

Bugs wrote:
I agree with Harold. The sine bar method will set the exact taper
angle, then use very fine cuts and Prussian blue to make the final
passes.
Bugs

"Hul Tytus" wrote in message
...
What brand of Prussian Blue are you using? I haven't found anything
currently that matches it.

I can't speak for others, but the tube I have in my toolbox was made by
Permatex. I've had it for, easily, 40 years. It's old enough that the
address is listed as Brooklyn 35, N.Y., before zip codes.

One need not buy much of this stuff. A small tube, when properly used, is
capable of covering the earth a couple times over.

Harold

Hul Tytus wrote:
What brand of Prussian Blue are you using? I haven't found anything
currently that matches it.
I use Canode spotting dyes because they are less messy. They are
not as good as real prussian blue, but then I'm not scraping things
to the single micro-inch level. But, I used to use Dykem brand
"Hi Spot Blue" in little squeeze tubes of 4 Oz ea, I think.
But, I HATE the mess. MSC, J&L, Travers, etc. all carry the
Dykem brand. The Canode is hard to get ahold of in small quantities.
I just found some at the Cummins outlet store, but I have no idea if
they have this at all branches.

Jon

Go to any art supply store. They will sell you as much Prussian Blue
[oil color] as you can use in a lifetime.
Bugs

And a hearty "Thanx guys" to all respondents!

All of your insightful and informed replies caused me to rethink the crux of
that particular biscuit. Bottom line: I was doing it wrong!

Although I couldn't see anything wrong with the idea of a "paper-drag" gage,
your suggestions to go with a dial test indicator really straightened me
out. I applied my little Starret Last Word indicator and surprise!
surprise! . . . it showed me I was trying to set up on the wrong angle. The
angle given in the handbooks for a plug taper is an "included" angle, thus
my method of paper-drag gaging was way uncool. Half the indluded angle
must be used when setting up to cut tapers.

So, by switching to the advice of experts, and a little common sense, the
error of my ways soon became apparent. I should have used a dial test
indicator in the first place. I have cut tapers before but always with the
compound on my 13 x 40 lathe. This time I wanted to practice with the
Sherline and its compound. Sherlines don't ordinarily come with compounds.
I bought the optional Sherline compound some time ago and never really tried
to do any serious work with it. Sherline suggests cutting tapers by setting
the head stock over or turning "between centers". There is no way to cut an
internal taper between centers. Besides, there is something alien to me
about turning anything between centers. Maybe next time I cut internal
tapers I will try Sherline's recommended method of setting the head stock
over. In retrospect, that is what I should have done in the first place.
It would be very easy to place the work in a collet or 4-jaw chuck, meter
with an indicator, and set the head stock over 1/2 the published taper
angle.

Bob Swinney

On Sat, 11 Mar 2006 22:46:19 -0600, "Robert Swinney"
wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.
The compound was set against a standard MT by feeling the taper and setting
it for constant drag on a piece of paper, through the length of taper. The
material is 12 L 14. Each attempt resulted in a taper alright, and one that
would lock, but there would be a lot of runout depending on how carefully I
positioned a test taper in the new socket. It appears the taper (socket) is
a loose fit on the small end. I expect the taper male to fit solidly in the
socket and be automatically aligned straight with just a tap from a plastic
hammer. Not the case. Any suggestionss - please. Is there a better way
than "feeling up" an accurate standard taper, like I'm doing. So far I
haven't tried the chalk or layout blue method of determining fit. The throw
is so short that there is only a very small window of adjustment on a MT #1.

Bob Swinney


Ignoring the comments and advice the others have given, there is one other
thing.. If the tool is above or below the centre line at all, the taper will
be large at the small end. The taper will also not be a conical shape. So
that's another thing to check.


Regards
Mark Rand
RTFM

According to Gunner :
On Sat, 11 Mar 2006 22:46:19 -0600, "Robert Swinney"
wrote:

I've been practicing boring a MT #1 with the compound on my Sherline lathe.
The results, after 4 tries are pretty dismal to say the least.

[ ... ]

Too thin a boring bar and too flexable a lathe. Shrug.. Its actually
better to drill and ream a #1 cause the tooling is by nature gonna be
pretty thin

I was having the same issues with a #2, even when doing it on a
Hardinge HLV-H..the best results were with very high spindle speeds
and tiny cuts towards the end. Stuff was deflecting.

Of course. I can't imagine boring a #1 MT on any machine which
I have. A #2 can get you close enough so a finish reamer can clean it
up rather nicely.

So I scounged a set of #2 roughing and finish reamers.

This works SO much better now

Since the setup is already done, bore the taper with that, and
then use the finish reamer to take the last little bit off.

And pick up a Morse taper gauge (the opposite gender from what
you are making), and use that with the spotting blue (Dykem, or other
brands, but *not* the layout blue from Dykem or others. :-)

I've so far gotten matching male and female Morse taper gauges
in #1, #2, and #3, and keep them in the same toolbox bar as the sine
bars and the Dykem spotting blue.

And -- yes, I have the finish reamers -- in #1 through #5 in a
single set, and a #0 stored in there as well. If I were making the
taper sockets regularly, I would also get the roughing reamers, to save
the setup time of the taper attachment to match what is needed.

Enjoy,
DoN.

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