I'm not being very successful using this tool - I think because I don't know
if it wants rake or not - should the top (cutting) edge be horizontal,
tilted down (e.g. perpendicular to the back of the HSS bit) or tilted up?
should it have any side rake? I know how to thread, that's not the problem,
I just don't know how this tool wants to be ground, and the Aloris catalog
isn't much help.

--
Bill
www.wbnoble.com

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread, that's
not the problem, I just don't know how this tool wants to be ground, and
the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


Here's a rule of thumb that should help you understand form tools, of which
threading tools are one.

Any time you alter the top surface of a tool, such that it no longer is on
the centerline at (all of) the point(s) of contact, you change the geometry
of the tool. It may not be much, but the change can be significant in that
it can effect how the tool performs.

When threading, unless an insert has been designed with rake, the tool
should remain flat, parallel with the centerline of the spindle. No rake!
To add rake of any description alters the tool's ability to take plunge
cuts, which can be VERY useful when taking a thread to size, providing an
excellent surface finish.

I am not familiar with the tool in question, so I may be wrong in that
particular case.

Harold

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread, that's
not the problem, I just don't know how this tool wants to be ground, and
the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


So what's the problem? Chatter, squeal, heat?

On Feb 10, 2:26*am, "Bill Noble" wrote:
I'm not being very successful using this tool - I think because I don't know
if it wants rake or not - should the top (cutting) edge be horizontal,
tilted down (e.g. perpendicular to the *back of the HSS bit) or tilted up?
should it have any side rake? *I know how to thread, that's not the problem,
I just don't know how this tool wants to be ground, and the Aloris catalog
isn't much help.

--
Billwww.wbnoble.com

I leave the top of threading bits dead flat when I surface-grind them
precisely. They won't take quite as big a chip as the hand-ground ones
with top rake but they certainly do work, even HSS on stainless.

jw

As Harold said, the top should be perfectly flat. AFAIK, the term "side rake" does not apply to
threading (form) tools. Lately I have been learning to cut miniature threads. This is done with a
standard carbide threading tool except the flat on top is not 1/8th pitch as per normal.
Machinery's Handbook says the flat on the tip which forms the root of external threads should be
about .321 x pitch rather than .125 x pitch. I've been practicing single-pointing 00-90 threads in
drill rod; ultimate goal being to make some very small taps and dies. Standard threading tools are
reground and sharpened with a 1200 grit diamond wheel; Glendo's Accu-finish Series One. It took me
a while to tumble to the idea of very small advances of the tool. In drill rod, anything larger
than aprox. .0003" per pass will break the tool's point. In brass, I can get away with .0005"
advance per pass. Without Glendo's diamond sharpening rig, I would have gone broke buying new tools
every time the point gave way during the learning cycle.

Bob Swinney


"Jim Wilkins" wrote in message
...
On Feb 10, 2:26 am, "Bill Noble" wrote:
I'm not being very successful using this tool - I think because I don't know
if it wants rake or not - should the top (cutting) edge be horizontal,
tilted down (e.g. perpendicular to the back of the HSS bit) or tilted up?
should it have any side rake? I know how to thread, that's not the problem,
I just don't know how this tool wants to be ground, and the Aloris catalog
isn't much help.

--
Billwww.wbnoble.com

I leave the top of threading bits dead flat when I surface-grind them
precisely. They won't take quite as big a chip as the hand-ground ones
with top rake but they certainly do work, even HSS on stainless.

jw

"Elliot G" wrote in message
m...

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread, that's
not the problem, I just don't know how this tool wants to be ground, and
the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


So what's the problem? Chatter, squeal, heat?

the problem is tearout - the tool is tearing the metal not cutting it. I'm
going to regrind the top of the tool and try again, perhaps tonight

On Tue, 10 Feb 2009 19:51:46 -0800, "Bill Noble"
wrote:


"Elliot G" wrote in message
om...

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread, that's
not the problem, I just don't know how this tool wants to be ground, and
the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


So what's the problem? Chatter, squeal, heat?

the problem is tearout - the tool is tearing the metal not cutting it. I'm
going to regrind the top of the tool and try again, perhaps tonight

You are either way below center, or have very little side relief.

Gunner

"If the personal freedoms guaranteed by the Constitution inhibit the government's ability to govern the people,
we should look to limit those guarantees."

Bill Clinton 1993-08-12

"Harold and Susan Vordos" wrote in message
...

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread, that's
not the problem, I just don't know how this tool wants to be ground, and
the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


Here's a rule of thumb that should help you understand form tools, of
which threading tools are one.

Any time you alter the top surface of a tool, such that it no longer is on
the centerline at (all of) the point(s) of contact, you change the
geometry of the tool. It may not be much, but the change can be
significant in that it can effect how the tool performs.

When threading, unless an insert has been designed with rake, the tool
should remain flat, parallel with the centerline of the spindle. No
rake! To add rake of any description alters the tool's ability to take
plunge cuts, which can be VERY useful when taking a thread to size,
providing an excellent surface finish.

I am not familiar with the tool in question, so I may be wrong in that
particular case.

Harold


well, you were right - when I got this, it had a fairly significant negative
rake and I just couldn't convince myself that it was ground wrong - which in
retrospect should have been obvious - anyway, when I reground it so the top
surface was level rather than negative, it worked great and I was able to
complete the job I was attempting to do.

Another learning experience ---- thanks

Gunner Asch wrote:

You are either way below center, or have very little side relief.

If it is what I think it is, it has no side relief.
http://www.use-enco.com/ProductImages/0906120-11.jpg



It *can* be rotated to match the pitch angle of the threads.

Positive side rake and positive top rake should help.


Wes

"Robert Swinney" wrote in message
...
As Harold said, the top should be perfectly flat. AFAIK, the term "side
rake" does not apply to
threading (form) tools. Lately I have been learning to cut miniature
threads. This is done with a
standard carbide threading tool except the flat on top is not 1/8th pitch
as per normal.
Machinery's Handbook says the flat on the tip which forms the root of
external threads should be
about .321 x pitch rather than .125 x pitch. I've been practicing
single-pointing 00-90 threads in
drill rod; ultimate goal being to make some very small taps and dies.
Standard threading tools are
reground and sharpened with a 1200 grit diamond wheel; Glendo's
Accu-finish Series One. It took me
a while to tumble to the idea of very small advances of the tool. In
drill rod, anything larger
than aprox. .0003" per pass will break the tool's point. In brass, I can
get away with .0005"
advance per pass. Without Glendo's diamond sharpening rig, I would have
gone broke buying new tools
every time the point gave way during the learning cycle.

Bob Swinney


Robert,

I spent a few days trying to get decent threads for making 0-80 and 00-90
taps in O1 drill rod. I found I needed to use a steady rest consisting of a
piece of bronze rod in the tailstock chuck that had been drilled with a
drill held in the headstock collet. An endmill was then used to mill about
a 120 deg section of the rod away through which the threading tool can reach
the rod to be threaded. With this, you can do the full depth in about 3
passes. It prevents the rod being threaded from bending away or up.

I was using a heavily modified 7x10 with two additional change wheels held
in on bars that bolt to the change wheel banjo.

On my lathe, I found I could only get a consistant cut if the tool was set a
couple thou high and then finger pressure was used to preload the tool back
to the proper height. With the tool set on center, there was enough flex in
the system to push the tool too low to cut properly, and if it was set
higher, it wouldn't cut. With the tool pushed down (couple of pounds
pressure) it would consistently cut a nice curl. I was just hand grinding
the HSS tool, and the finish was not as nice as I would have liked, but I
did end up threading about 60 stainless 1/16" rods to 0-80, made several
taps, and another 20 studs in 00-90.

Then I found a set of 00-90 and 0-80 taps on ebay for something like $12.
Much nicer than my homemade taps. And the bought taps were used to make
better dies than I could make with my homemade taps. I think the same
seller has another set ( may have recently sold ). Maybe he regularly lists
these. It got me thinking that I would like to set up a rig to grind the
threads vice cut them. Not sure if I would use the lathe, my homemade tool
and cutter grinder or a purpose built machine.

Wayne Sippola


"Jim Wilkins" wrote in message
...
On Feb 10, 2:26 am, "Bill Noble" wrote:
I'm not being very successful using this tool - I think because I don't
know
if it wants rake or not - should the top (cutting) edge be horizontal,
tilted down (e.g. perpendicular to the back of the HSS bit) or tilted
up?
should it have any side rake? I know how to thread, that's not the
problem,
I just don't know how this tool wants to be ground, and the Aloris
catalog
isn't much help.

--
Billwww.wbnoble.com

I leave the top of threading bits dead flat when I surface-grind them
precisely. They won't take quite as big a chip as the hand-ground ones
with top rake but they certainly do work, even HSS on stainless.

jw

Wayne, I'd be very interested to know more about the details involved in the
proess you described here.

If you happen to use this setup again for something similar, please take
some pictures to share with the rest of us.

The lathe modification of adding gears is interesting too.

If you have web pages showing any of the setups, please post the URLs.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html



"Wayne S" wrote in message
el...

"Robert Swinney" wrote in message
...
As Harold said, the top should be perfectly flat. AFAIK, the term "side
rake" does not apply to
threading (form) tools. Lately I have been learning to cut miniature
threads. This is done with a
standard carbide threading tool except the flat on top is not 1/8th pitch
as per normal.
Machinery's Handbook says the flat on the tip which forms the root of
external threads should be
about .321 x pitch rather than .125 x pitch. I've been practicing
single-pointing 00-90 threads in
drill rod; ultimate goal being to make some very small taps and dies.
Standard threading tools are
reground and sharpened with a 1200 grit diamond wheel; Glendo's
Accu-finish Series One. It took me
a while to tumble to the idea of very small advances of the tool. In
drill rod, anything larger
than aprox. .0003" per pass will break the tool's point. In brass, I can
get away with .0005"
advance per pass. Without Glendo's diamond sharpening rig, I would have
gone broke buying new tools
every time the point gave way during the learning cycle.

Bob Swinney


Robert,

I spent a few days trying to get decent threads for making 0-80 and 00-90
taps in O1 drill rod. I found I needed to use a steady rest consisting of
a
piece of bronze rod in the tailstock chuck that had been drilled with a
drill held in the headstock collet. An endmill was then used to mill
about
a 120 deg section of the rod away through which the threading tool can
reach
the rod to be threaded. With this, you can do the full depth in about 3
passes. It prevents the rod being threaded from bending away or up.

I was using a heavily modified 7x10 with two additional change wheels held
in on bars that bolt to the change wheel banjo.

On my lathe, I found I could only get a consistant cut if the tool was set
a
couple thou high and then finger pressure was used to preload the tool
back
to the proper height. With the tool set on center, there was enough flex
in
the system to push the tool too low to cut properly, and if it was set
higher, it wouldn't cut. With the tool pushed down (couple of pounds
pressure) it would consistently cut a nice curl. I was just hand grinding
the HSS tool, and the finish was not as nice as I would have liked, but I
did end up threading about 60 stainless 1/16" rods to 0-80, made several
taps, and another 20 studs in 00-90.

Then I found a set of 00-90 and 0-80 taps on ebay for something like $12.
Much nicer than my homemade taps. And the bought taps were used to make
better dies than I could make with my homemade taps. I think the same
seller has another set ( may have recently sold ). Maybe he regularly
lists
these. It got me thinking that I would like to set up a rig to grind the
threads vice cut them. Not sure if I would use the lathe, my homemade
tool
and cutter grinder or a purpose built machine.

Wayne Sippola

"Wes" wrote in message
...
Gunner Asch wrote:

You are either way below center, or have very little side relief.

If it is what I think it is, it has no side relief.
http://www.use-enco.com/ProductImages/0906120-11.jpg



It *can* be rotated to match the pitch angle of the threads.

Positive side rake and positive top rake should help.


Wes


Wes,

Both should be avoided like the plague. Each effects the tool's ability
to generate a correct form, but not in a good way.

When you introduce rake, the tool no longer makes contact at the
centerline----
When you introduce side rake, one side is positive, the other is negative,
which is an absolute no-no.

Keep threading tools flat and on center for best results. Also, keep them
sharp. Very sharp!

Harold

"Bill Noble" wrote in message
...

"Harold and Susan Vordos" wrote in message
...

"Bill Noble" wrote in message
...
I'm not being very successful using this tool - I think because I don't
know if it wants rake or not - should the top (cutting) edge be
horizontal, tilted down (e.g. perpendicular to the back of the HSS bit)
or tilted up? should it have any side rake? I know how to thread,
that's not the problem, I just don't know how this tool wants to be
ground, and the Aloris catalog isn't much help.

--
Bill
www.wbnoble.com


Here's a rule of thumb that should help you understand form tools, of
which threading tools are one.

Any time you alter the top surface of a tool, such that it no longer is
on the centerline at (all of) the point(s) of contact, you change the
geometry of the tool. It may not be much, but the change can be
significant in that it can effect how the tool performs.

When threading, unless an insert has been designed with rake, the tool
should remain flat, parallel with the centerline of the spindle. No
rake! To add rake of any description alters the tool's ability to take
plunge cuts, which can be VERY useful when taking a thread to size,
providing an excellent surface finish.

I am not familiar with the tool in question, so I may be wrong in that
particular case.

Harold


well, you were right - when I got this, it had a fairly significant
negative rake and I just couldn't convince myself that it was ground
wrong - which in retrospect should have been obvious - anyway, when I
reground it so the top surface was level rather than negative, it worked
great and I was able to complete the job I was attempting to do.

Another learning experience ---- thanks




Welcome!

I figured that would be the case.

Harold

"Harold and Susan Vordos" wrote:

Both should be avoided like the plague. Each effects the tool's ability
to generate a correct form, but not in a good way.

When you introduce rake, the tool no longer makes contact at the
centerline----
When you introduce side rake, one side is positive, the other is negative,
which is an absolute no-no.


I stand corrected. I was thinking of a good finish and you pointed out affects on form.

Keep threading tools flat and on center for best results. Also, keep them
sharp. Very sharp!

I wonder what the best way is to sharpen that style of threading tool?

Wes

On Thu, 12 Feb 2009 17:16:39 -0500, Wes wrote:

"Harold and Susan Vordos" wrote:

Both should be avoided like the plague. Each effects the tool's ability
to generate a correct form, but not in a good way.

When you introduce rake, the tool no longer makes contact at the
centerline----
When you introduce side rake, one side is positive, the other is negative,
which is an absolute no-no.


I stand corrected. I was thinking of a good finish and you pointed out affects on form.

Keep threading tools flat and on center for best results. Also, keep them
sharp. Very sharp!

I wonder what the best way is to sharpen that style of threading tool?

Wes


Send it out.

Gunner

"If the personal freedoms guaranteed by the Constitution inhibit the government's ability to govern the people,
we should look to limit those guarantees."

Bill Clinton 1993-08-12

"Gene" wrote in message
news
On Thu, 12 Feb 2009 05:10:34 GMT, "Harold and Susan Vordos"
wrote:



Good advice. Also, don't buy into the mythological tale that all
threading is done with the compound, which is always set at 29.5
degrees. (That was good advice circa 1900 when using stringy hot
rolled stock. Certainly, you aren't doing *that* are you??)

Feed straight in with the cross feed, with a tool perfectly on center,
and zero rake..... you'll be fine! (12L14 is your friend......)
--


odd, everything I've read except your post says to use the 29 degree angle
to cut the amount of cutter edge in contact with the cut in half. My lathe
is only a 12X48 inch Logan/powermatic - I don't know if it is rigid enough
to do some of the things a larger lathe does, but I can try it some time

"Bill Noble" wrote:

odd, everything I've read except your post says to use the 29 degree angle
to cut the amount of cutter edge in contact with the cut in half. My lathe
is only a 12X48 inch Logan/powermatic - I don't know if it is rigid enough
to do some of the things a larger lathe does, but I can try it some time

Keep in mind that the tool pressure is going to go up. Not an issue if part doesn't
deflect easily but on long and slender stuff, it matters.

Wes

"Bill Noble" wrote in message
...

"Gene" wrote in message
news
On Thu, 12 Feb 2009 05:10:34 GMT, "Harold and Susan Vordos"
wrote:



Good advice. Also, don't buy into the mythological tale that all
threading is done with the compound, which is always set at 29.5
degrees. (That was good advice circa 1900 when using stringy hot
rolled stock. Certainly, you aren't doing *that* are you??)

Feed straight in with the cross feed, with a tool perfectly on center,
and zero rake..... you'll be fine! (12L14 is your friend......)
--


odd, everything I've read except your post says to use the 29 degree angle
to cut the amount of cutter edge in contact with the cut in half. My
lathe is only a 12X48 inch Logan/powermatic - I don't know if it is rigid
enough to do some of the things a larger lathe does, but I can try it some
time

There's a lot of conflict with chip flow when plunge threading. I do not
recommend you do it, although material choices and spindle speeds make a
huge difference.

Point pressure on threading tools is extreme due to the narrow tool and
depth of cut. Adding chip flow conflicts to the mix is a recipe for tool
failure. Stick with the compound for better tool life. Plunge thread
for finish passes, which will clean up the back side of the thread. Tool
must be VERY sharp, and depth of cut must be shallow, .002" max., with less
desirable.

Modern machinery (CNC's) that are capable of extreme spindle speeds tend to
have much better results with plunge threading, although I'd avoid doing so
even then if I had the option. You'll get much better tool life by feeding
at 29 degrees.

Harold

On Thu, 12 Feb 2009 21:39:50 -0800, "Bill Noble"
wrote:


"Gene" wrote in message
news
On Thu, 12 Feb 2009 05:10:34 GMT, "Harold and Susan Vordos"
wrote:



Good advice. Also, don't buy into the mythological tale that all
threading is done with the compound, which is always set at 29.5
degrees. (That was good advice circa 1900 when using stringy hot
rolled stock. Certainly, you aren't doing *that* are you??)

Feed straight in with the cross feed, with a tool perfectly on center,
and zero rake..... you'll be fine! (12L14 is your friend......)
--


odd, everything I've read except your post says to use the 29 degree angle
to cut the amount of cutter edge in contact with the cut in half. My lathe
is only a 12X48 inch Logan/powermatic - I don't know if it is rigid enough
to do some of the things a larger lathe does, but I can try it some time

Well, now you're going to read another point of view.

I almost always use a 10 degree infeed when cutting a 60 degree
thread. Read it many years ago in a Kennametal catalog, and it was
recommended as a compromise between the 29 degree, where the trailing
edge is dragging and 0 degree where chip flow becomes a problem.

I've been using this for many years, mostly on Logan 12" and 14"
lathes and have been very happy. Granted, I am using carbide inserts
and high speeds (or at least as high as I can). I don't usually use
back gear, except on very large diameter threads, or if I have to
thread up to a shoulder. Even then, I've gotten pretty good at
stopping and retracting pretty quick, even cutting threads without an
undercut and using my eye to retract at the same point.

'Course, it helps to have a LOT of practice/experience!

Even nicer, when I can, to use CNC. Speed is limited by carbide
cutting speeds and CPU processor speed (limiting effective feedrate to
100 IPM). Cutting 1/2-20 threads at 1900 RPM is a joy to behold!


--
+--------------------------------------------+
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| Logan Actuator Co. http://www.lathe.com |
| Harvard, IL |
|++++++++++++++++++++++++++++++++++++++++++++|
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| Montgomery Wards Lathes |
| Logan-Lilly Mine Hoist Safety Controllers |
+--------------------------------------------+
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