On Sun, 29 Sep 2013 18:10:05 -0500, Karl Townsend
wrote:

I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.

Karl


You are going to have to drill and then braze /weld on an extension.

Good luck!!

Gunner

"The socialist movement takes great pains to circulate frequently new labels for its ideally constructed state.
Each worn-out label is replaced by another which raises hopes of an ultimate solution of the insoluble basic
problem of Socialism, until it becomes obvious that nothing has been changed but the name.
The most recent slogan is "State Capitalism."[Fascism] It is not commonly realized that this covers nothing more
than what used to be called Planned Economy and State Socialism, and that State Capitalism, Planned Economy,
and State Socialism diverge only in non-essentials from the "classic" ideal of egalitarian Socialism. - Ludwig von Mises (1922)

On Sun, 29 Sep 2013 21:35:16 -0500, Ignoramus11700
wrote:

Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

You are NOT..NOT going to be able to use a boring bar in a 24" deep
hole thats 1" in diameter.

You might use a "Line Boring" setup...but not a boring bar. End
program. Full Stop. EnditEnditEndit.

Gun drill yes. Line boring yes, no boring bars. There is simply
nothing..nothing stiff enough to work. not even carbide.

Gunner


i

On 2013-09-29, Karl Townsend wrote:
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.

Karl


"The socialist movement takes great pains to circulate frequently new labels for its ideally constructed state.
Each worn-out label is replaced by another which raises hopes of an ultimate solution of the insoluble basic
problem of Socialism, until it becomes obvious that nothing has been changed but the name.
The most recent slogan is "State Capitalism."[Fascism] It is not commonly realized that this covers nothing more
than what used to be called Planned Economy and State Socialism, and that State Capitalism, Planned Economy,
and State Socialism diverge only in non-essentials from the "classic" ideal of egalitarian Socialism. - Ludwig von Mises (1922)

On Mon, 30 Sep 2013 00:08:14 -0500, Ignoramus11700
wrote:

On 2013-09-29, Gunner Asch wrote:
On Sun, 29 Sep 2013 21:35:16 -0500, Ignoramus11700
wrote:

Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

You are NOT..NOT going to be able to use a boring bar in a 24" deep
hole thats 1" in diameter.

You might use a "Line Boring" setup...but not a boring bar. End
program. Full Stop. EnditEnditEndit.

Gun drill yes. Line boring yes, no boring bars. There is simply
nothing..nothing stiff enough to work. not even carbide.

EVen making very small cuts?

Ayup..even small cuts. One of the unavoidable facts of life that
Achimedes discovered..."Give me a long enough lever and I can move the
world"


"The socialist movement takes great pains to circulate frequently new labels for its ideally constructed state.
Each worn-out label is replaced by another which raises hopes of an ultimate solution of the insoluble basic
problem of Socialism, until it becomes obvious that nothing has been changed but the name.
The most recent slogan is "State Capitalism."[Fascism] It is not commonly realized that this covers nothing more
than what used to be called Planned Economy and State Socialism, and that State Capitalism, Planned Economy,
and State Socialism diverge only in non-essentials from the "classic" ideal of egalitarian Socialism. - Ludwig von Mises (1922)

I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.

Karl

"Karl Townsend" wrote in message
...
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.


You just need a long holder; the endmill can be one of those cheapo 1/2in
shank jobbies like Enco sells for hand mills although I would probably first
go through with a slightly undersized silver and deming, retracting fully at
very frequent intervals.

Karl Townsend wrote:

I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.

Karl


Might it be easier to get 12" and 24" gun drills and just change drills
after you bottom out the shorter one? That way you don't have some sort
of monstrosity hanging off the toolholder.

On Sun, 29 Sep 2013 17:51:11 -0700, "PrecisionmachinisT"
wrote:


"Karl Townsend" wrote in message
.. .
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.


You just need a long holder; the endmill can be one of those cheapo 1/2in
shank jobbies like Enco sells for hand mills although I would probably first
go through with a slightly undersized silver and deming, retracting fully at
very frequent intervals.


Thanks for the idea. I didn't know they made 1/2 shank by 7/8
endmills. Just the ticket.

Yes, i didn't mention, I'll ruff drill it first. Just use the endmill
to true it up.

Karl

Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

i

On 2013-09-29, Karl Townsend wrote:
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.

Karl

"Ignoramus11700" wrote in message
...
Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

i


I would rough drill then use a push broach in a hydraulic
press to achive the desired final size. This eliminates a
lot of problems like tapered hole when trying to bore
small sized diameters. Even drilling a long 24" hole say
12" deep on each end then broaching it will result a straight
uniform non-tapered hole. Making a push broach out of
worn taps or tool bits is easy on a tool and cutter grinder.

Best Regards
Tom.
--
http://fija.org/

On 2013-09-29, Gunner Asch wrote:
On Sun, 29 Sep 2013 21:35:16 -0500, Ignoramus11700
wrote:

Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

You are NOT..NOT going to be able to use a boring bar in a 24" deep
hole thats 1" in diameter.

You might use a "Line Boring" setup...but not a boring bar. End
program. Full Stop. EnditEnditEndit.

Gun drill yes. Line boring yes, no boring bars. There is simply
nothing..nothing stiff enough to work. not even carbide.

EVen making very small cuts?

"Karl Townsend" wrote in message
...
On Sun, 29 Sep 2013 17:51:11 -0700, "PrecisionmachinisT"
wrote:


"Karl Townsend" wrote in message
. ..
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

Not an easy task. I wouldn't ask if it was easy. OK, a slight
misalignment at the center won't bother, so now I only need to bore
7".

My best idea to get it in perfect alignment is to mount an end mill
just under one inch in the spindle and bore with the square rod
mounted in position on the lathe. Then take the part out and bore to
correct diameter in the mill.

I just searched my stash, found a 5" long by 7/8" EM. I'd sure like
to find a longer one. Anybody have one? Quick search on fleabay, no
joy.

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel. The
drills mount in a one inch bore.


You just need a long holder; the endmill can be one of those cheapo 1/2in
shank jobbies like Enco sells for hand mills although I would probably
first
go through with a slightly undersized silver and deming, retracting fully
at
very frequent intervals.


Thanks for the idea. I didn't know they made 1/2 shank by 7/8
endmills. Just the ticket.

Yes, i didn't mention, I'll ruff drill it first. Just use the endmill
to true it up.


Alternate between a 7/8 in S&D drill and an endmill 1/16th or so smaller
than the finish hole that's been cicular ground and has about 1/2 degree of
backtaper , switching back to the drill after every inch or so in depth,
then finally, run your finish tool, removing .03 or so per side, preferably
in a single pass.

"Ignoramus11700" wrote in message
...
On 2013-09-29, Gunner Asch wrote:
On Sun, 29 Sep 2013 21:35:16 -0500, Ignoramus11700
wrote:

Karl, I think that most people would use a boring bar on the lathe in
this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

You are NOT..NOT going to be able to use a boring bar in a 24" deep
hole thats 1" in diameter.

You might use a "Line Boring" setup...

He *might* except he'd need a ~3/4 inch diameter solid carbide bar a tad
over 48 ionches long...

but not a boring bar. End
program. Full Stop. EnditEnditEndit.

Gun drill yes. Line boring yes, no boring bars. There is simply
nothing..nothing stiff enough to work. not even carbide.

EVen making very small cuts?

...LOL..

On Mon, 30 Sep 2013 00:08:14 -0500, Ignoramus11700
wrote:

On 2013-09-29, Gunner Asch wrote:
On Sun, 29 Sep 2013 21:35:16 -0500, Ignoramus11700
wrote:

Karl, I think that most people would use a boring bar on the lathe in this
situation. Especially since you have a CNC and can write a program to
take off a small amount in each pass.

You are NOT..NOT going to be able to use a boring bar in a 24" deep
hole thats 1" in diameter.

You might use a "Line Boring" setup...but not a boring bar. End
program. Full Stop. EnditEnditEndit.

Gun drill yes. Line boring yes, no boring bars. There is simply
nothing..nothing stiff enough to work. not even carbide.

EVen making very small cuts?
=======================

Long response

If at all possible, rethink your material requirements and
use something like sched 80/120 pipe or heavy DOM tubing.

To do this from solid stock is possible, but won't be cheap
or easy. The project divides into two parts, both of which
involve considerable construction of tools and tooling.
First getting a nominal size hole the length of the stock,
and then getting the hole to the required dimensions, finish
and straightness.

Assuming a reasonably equipped HD home/hobby machine shop,
this can be done, but the set-up, tool/fixture fabrication
etc. will take *MANY* times as long as the machining, and
the machining will likely be an all day job (or more,
depending on materials/ tollerances(yours and the machine)
==for each phase.== A gun drill is most likely out of the
question because of the high pressure/volume pump required,
leaving the traditional methods of woodpeckering the hole in
phase I, and then line boring in phase II.

FWIW -- one of the reasons a gun drill works so well is that
it is guided at the head very close to the cutting edge so
there is no side load on the shaft/shank. The groove in the
side of the head and shank is to give the coolant and chips
some place to go. This is why you must have a finished bore
several diameters deep to start so the head can guide as
intended.

Phase I -- Making the initial hole.

Two possibilities:

Use the lathe as a horizontal drilling machine, or if the
spindle bore is big enough let it extend through the
spindle.

Most likely you have to use the lathe as a horizontal drill,
and you save one set-up.

You will have to fabricate an extension drill as a ready
made unit will be prohibitively expensive. In order to
minimize tooling size, with loss of bed travel, fabrication
of a faux collet to accept the drill extension will be
required. This can mount to a face plate or trued dog
driver. To avoid "whipping," extension of the drill should
be no more than necessary at any one time, and the workpiece
should never be pulled off the drill while the lathe is
running. Most likely you can fabricate an extension drill
using a 36 inch piece of 7/8 or 3/4 W1 drill rod [silver
steel for our brit posters]. Get a 63/64 Silver and Deming
drill, turn the shank to 3/8, and silversolder or epoxy in a
counterbore in one end of the drill rod. The counterboring
of the drillrod will be much more accurate and easier if you
fabricate the faux collet first and machine it on the face
plate or trued dog driver,== which should remain in place
until this phase of the job is completed for maximum
accuracy.== The faux collet is simply a plate, c. 1 inch
thick that can be bolted to the face plate with a slot
across the bore to allow a 3/8 shcs to pinch the loose side
down on the drill extension so it can be adjusted in/out
without losing zero. Because the end of the extension will
most likely extend beyond the end of the spindle, whip is a
danger, and will effect accuracy. Speed should be limited,
and it is worthwhile to fabricate an second chuck or spider
to fit the outer end of the spindle with set screws to
center the extension. Be careful of the screws as these will
rip skin and meat off in a heartbeat. Bushings to fit
between the spindle bore and the drill extension when it is
moved beyond the rear chuck can be very helpful. These can
be delrin as there is no great load as long as the shaft
remains centered.


Phase II -- to line bore a 24 inch hole, you will require a
lathe with a minimum of 50 inches between centers, with 54
or 60 even better to provide some working room. you will
have to fabricate a between centers line boring bar 50 to 60
inches long of a diameter just under one inch with adequate
chip/swarf clearance. You will need to provide a high
pressure/flow [not as high as required for a gun drill but
far greater than the normal home shop swamp cooler] to
insure adequate lubrication, heat control, and chip
evacuation. To minimize deflection it is a good idea to
drill the line boring bar for two tool bits in order to
minimize the off center or bowing forces on the line boring
bar. Most likely for ease of fabrication, round tool bits
should be used. These should be small as the holes are in
the weakest part of the bar and the clamp screws should not
be too big either. The bar should be accurately centered at
both ends, and should run between centers with a solid
center in the face plate or driver and an antifriction
center in the tail stock to eliminate the need for
lubrication. These are a right bitch to adjust as one tool
trails the other and you want the tools to have equal chip
load, i.e. the "rear" bit, which depends on which way you
are feeding, should take as deep a cut as the front tool.
There is a minimum depth of cut/feed rate, depending on the
material/condition for continuous cut and good surface
finish. You will also need to fabricate a boring table,
which replaces the compound [top slide for our Brit posters]
on the cross slide. The work piece [hole] *MUST* be
concentric to the lathe spindle axis, which again is a right
bitch to set up ( be sure you have *LOTS* of shims and
*LOTS* time) [If you use the lathe as a horizontal drilling
machine you only have to do this once.]

http://www.use-enco.com/CGI/INPDFF?PMPAGE=899&PMCTLG=00
http://www.use-enco.com/CGI/INPDFF?P...MITEM=301-1058
http://www.use-enco.com/CGI/INPDFF?P...MITEM=383-7005

Let the group know what you decide, and good luck

Ignoramus11700 fired this volley in
:

EVen making very small cuts?

Not even taking off mere swarf, Ig.

Lloyd

"Karl Townsend" wrote in message
...
I'm trying to bore a 1" hole 12" to 14" long in a 1.75" square rod
PERFECTLY on center to my CHNC lathe...

FWIW, I'm trying to gundrill 24" long in a lathe with 12" travel.
The
drills mount in a one inch bore.

Karl

How about using three guide hole blocks instead of one challengingly
long hole?

You could make a 1.75" box channel from flat stock with your 1" holes
in the end plates, and if necessary add one or more blocks within. If
sliding a drill rod through shows they aren't aligned, cut down the
inner one and locate with setscrews.

A 1.75" box channel made of 0.375" ground flat stock might be good
enough with just end plates, if you drill the dowel pin holes
accurately enough.
jsw

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
Ignoramus11700 fired this
volley in
:

EVen making very small cuts?

Not even taking off mere swarf, Ig.

Lloyd

I just tried boring some water pipe scrap with a 9/16" diameter
Armstrong boring bar extended 7.5" from the holder and set slightly
above center to let it deflect out of the cut. The pipe was chucked
close so all vibration came from the bar. It's slow at 0.002"/pass and
the finish is poor but it does work well enough to remove the welding
flash and recenter the hole to drill or ream it further.. Reducing
speed removed the chatter pattern.

1/2" pipe (0.840" OD) might be a good cheap candidate for a home-made
boring bar. The bit retaining screw threaded into the end could be a
3/8" pipe plug for Schedule 40 pipe, or a 5/8" machine screw for Sch80
Considering how readily my test setup chattered, enough to shift the
feed handles, I wouldn't run this unattended.
jsw