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Default Laying out and drilling an index disk

I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.
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Default Laying out and drilling an index disk

In message , John Weeks
writes
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.



Hi John, not exactly sure of the design of your indexing disk, ( A
picture would help - but not here)

Have you considered a different approach
24 is half of 48
48 is half of 96

Rather than drill 96 holes, is there a way you can apply an offset to
the indexing pin ?

I.e.

----------o
-----------------o
-----------------------o


On my chuck I have a number of holes which I can locate the indexing
pin into.

The indexing arm is fixed to the lathe.

But supposing the arm is square section . Make a sliding attachment that
has 3 pins in it.

Each pin offset from the index arm mount by say half inch the closest
pin to the chuck being half inch long the middle one being 3/4 inch and
the closest to the head stock being 1 inch. The reason for the length
variations is to ensure the next pin is clear of obstructions on the
chuck

If you have a round arm you could make a simple 4 way offset indexing
guide which rotates on the arm and is located by a pin in through the
shaft. Made from a square section with hole in middle to fit arm, you
then fit a pin in each face at a suitable offset.

There may be a minor issue with the curvature of the indexing ring , but
I am sure you can overcome it
--
John
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Default Laying out and drilling an index disk

On Tue, 28 Oct 2008 15:15:46 -0700, John Weeks wrote:

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.


How about drilling the 24 holes on the lathe and then making up a jig from
plywood (or whatever) and affix two dowels that will fit into any two
adjacent holes of the 24. Find the center and drill a guide hole for one
halfway in between. Repeat with a new jig for 96.

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Default Laying out and drilling an index disk

John,
What you are trying to do is, for all practical purposes, an impossible
task. The cumulative error you build in when going from hole to hole is
killing you. For an example, look at the 96 hole index disk. That's 360
deg. / 96 holes or 3.75 degrees per hole. But, if you are in error by only
0.05 degrees when you drill the first 2 holes, the cumulative error over 96
holes is approximately 1 degree - or about 1/4 the distance between two
holes. .05 degrees is a very small error when drilling holes with even very
high quality machine tools.
Jim Seelye

"John Weeks" wrote in message
...
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.



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Default Laying out and drilling an index disk

On Tue, 28 Oct 2008 22:57:10 +0000, John
wrote:


Hi John, not exactly sure of the design of your indexing disk, ( A
picture would help - but not here)

Have you considered a different approach
24 is half of 48
48 is half of 96

Rather than drill 96 holes, is there a way you can apply an offset to
the indexing pin ?

I.e.

----------o
-----------------o
-----------------------o


On my chuck I have a number of holes which I can locate the indexing
pin into.

The indexing arm is fixed to the lathe.

But supposing the arm is square section . Make a sliding attachment that
has 3 pins in it.

Each pin offset from the index arm mount by say half inch the closest
pin to the chuck being half inch long the middle one being 3/4 inch and
the closest to the head stock being 1 inch. The reason for the length
variations is to ensure the next pin is clear of obstructions on the
chuck

If you have a round arm you could make a simple 4 way offset indexing
guide which rotates on the arm and is located by a pin in through the
shaft. Made from a square section with hole in middle to fit arm, you
then fit a pin in each face at a suitable offset.

There may be a minor issue with the curvature of the indexing ring , but
I am sure you can overcome it


I understand in your suggestion. My built in index is inside the
headstock, there is a spring loaded pin that goes through the
headstock to lock the shaft.

I've got index holes on my Vicmarc chuck, but I want to be able to
index things on a faceplate.

Thanks for the idea, though.

JW


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Default Laying out and drilling an index disk

On Tue, 28 Oct 2008 18:50:38 -0500, "seelyjv"
wrote:

John,
What you are trying to do is, for all practical purposes, an impossible
task.


Yep. Pretty much what I've concluded.

The cumulative error you build in when going from hole to hole is
killing you. For an example, look at the 96 hole index disk. That's 360
deg. / 96 holes or 3.75 degrees per hole. But, if you are in error by only
0.05 degrees when you drill the first 2 holes, the cumulative error over 96
holes is approximately 1 degree - or about 1/4 the distance between two
holes. .05 degrees is a very small error when drilling holes with even very
high quality machine tools.
Jim Seelye

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Default Laying out and drilling an index disk


"John Weeks" wrote: (clip) Anybody have any better way of doing this?
^^^^^^^^^^^^^^^^^
One of our club members had a large number of indexing disks with different
spacings, which he did by using other devices to get the spacing. He would
clamp a saw blade or a gear. etc. to the spindle, and use a positioning tab
to drop into the notches (saw teeth, gear teeth, etc), and then make the new
disk. His disks were not drilled--they were notched, but the idea is the
same.


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Default Laying out and drilling an index disk

On Tue, 28 Oct 2008 17:15:46 -0500, John Weeks wrote
(in message ):

I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.


I am thinking that using the built-in indexing capability would be the way to
go. Instead of measuring and locating every hole, it would be much simpler to
accurately locate just one hole, and then let the lathe do the rest.
tom koehler


--
I will find a way or make one.

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Default Laying out and drilling an index disk

John - a couple of thoughts

first and most importantly - are you using a center drill for this?
otherwise the drill itself will wander.
second, drill opposites - e.g. drill hole 1, then drill the hole 180 deg
opposite hole 1 so only 1/2 error can accumulate
if possible, drill by bisecting angles
always center punch first - use dykem and a sharp scribe to layout


"John Weeks" wrote in message
...
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.



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Default Laying out and drilling an index disk

On Oct 28, 6:15*pm, John Weeks wrote:
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block *into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.


I think the best tool for the job is the one your using right now.
Your computer as it is incredibly accurate. Find a drawing program
that will allow you to draw a pie graph with as many segments as you
need or even a segmenting program like woodturner pro which will let
you print out a picture of a finished ring. Make your inside dimension
0 and your outside dimension whatever diameter you want. Set it for as
many segments as you need and print it out. You could then glue it to
a piece of plywood. You could get all the corresponding perpendicular
points with a compass. Of course this is where human error would begin
if your compass wasn't exactly in the center but I would guess
negligible. With a very sharp awl mark all the perpendicular points
and drill them on the drill press with an accurate drill like a
forstner. To mount it to a faceplate turn a dowel the exact diameter
as the hole in the face of your faceplate and drill a hole in the
template the same size and it should be well centered. You could
actually find your perpendicular points once the disc was mounted to
the lathe by holding a pencil on the spinning disc at whatever
diameter you wanted. I don't know if this is what your looking for or
if it pertains to your project but it certainly would make an
extremely accurate indexing disc. Bob
http://www.outofcontrol-woodturning.com


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On Tue, 28 Oct 2008 21:43:11 -0700, "Bill Noble"
wrote:

John - a couple of thoughts

first and most importantly - are you using a center drill for this?
otherwise the drill itself will wander.
second, drill opposites - e.g. drill hole 1, then drill the hole 180 deg
opposite hole 1 so only 1/2 error can accumulate
if possible, drill by bisecting angles
always center punch first - use dykem and a sharp scribe to layout


All Right! Thanks to suggestions from Bill and others, I've got a nice
index wheel, 15" in diameter, in 1/4" hardboard. The wheel will
rotate in a slot in a piece of 2x2 clamped to the lathe bed, with a
hole through the 2x2 for the pin.

I can't believe I was actually reaching around my brad point bits to
get the set of ordinary drill bits! Using the brad point bit allowed
be to get very good location by eye - I could just touch the surface
then raise the bit to check and reposition if necessary.

I tried using a center punch, then realized I was having to locate the
point in two dimensions by eye. Since the disk was going to rotate
under the drill on a fixed pin, I decided this wasn't necessary. If
I'd been drilling in metal that might have been required.

I'm laying out lines on wood for carving by hand - I don't need
thousandths of an inch accuracy.
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Default Laying out and drilling an index disk

I have also found that local machine shops can do this for remarkablr
reasonable prices (unless your working in some really odd dimension).

If that si not an option, a good drawing prgoram 9there are free versions of
CAD that can do this) and any non-dot-matrix printer can get you a layout
star that is with in pixel (print as high res as your printer allows)..

-JAmes



"John Weeks" wrote in message
...
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.



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Default Laying out and drilling an index disk

On Oct 28, 6:15�pm, John Weeks wrote:
I've been trying to construct and indexing disk for my lathe."


Why not buy one at www.alisam.com or on Ebay? Fits midi lathes and a
new larger indexing system for 10 to 24 inch lathes!

Tim
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Why spend $80 when a $2 piece of hardboard will do the job?

On Thu, 30 Oct 2008 07:39:33 -0700 (PDT), Tim wrote:

On Oct 28, 6:15?pm, John Weeks wrote:
I've been trying to construct and indexing disk for my lathe."


Why not buy one at www.alisam.com or on Ebay? Fits midi lathes and a
new larger indexing system for 10 to 24 inch lathes!

Tim

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On Oct 28, 2:15*pm, John Weeks wrote:
I've been trying to construct and indexing disk for my lathe. It has
24 hole indexing built in, but I want 48 and 96 as well. I'm trying to
come up with the best way to lay out the holes and dril them on the
drill press. My first thought was to use a pin guide, something like
cutting box joints on a table saw, to avoid having to position the
drill bit by eye.

I carefully drilled the first two 3/16th inch holes the correct
distance apart, carefully positioning the disk with a 1/16th inch
drill in the chuck, clamping thedisk down, then switching to a 3/16th
inch bit and drilling the hole. The center of the disk is revolving on
a pin at the radius I wanted. Then, with the bit in the 2nd hole, I
pressed a pin through a guide block *into the first hole and clamped
the guide block in place.

I should be able to remove the pin, rotate the second hole under under
the guide, position it with the pin, drill the third hole, etc.

It's not working. When I get around the diameter I have lost or gained
a third to a half the distance between the holes. The drill press
table is locked down tight, the pin is a good tight fit. But there is
slop creeping in someplace.

This time I'm going to print a compass template with 48 radii and
position the bit by eye. The individual holes may be off slightly but
they should each be within a certain degree of error from the right
point.

Anybody have any better way of doing this?

I thought about using the index on the lathe, drilling the 24 holes,
then slipping the disk half the distance and going around again. But
I'd have to build a positioning jig for lathe drilling first.

JW.


Hello John,

I didn't see this message until today. Now, I'm sure that I need to
get another way to read the newsgroup.

In relation to your question, I've made a number of indexing wheels
over the years. The easiest way is to use Woodturner PRO or one of the
other segmenting projects. Select a ring diameter that will print onto
an 8-1/2 x 11 inch page. Set the center diameter to the diameter of
your lathe spindle; i.e. 1", 1-1/4", etc. Then set the number of
segments to 96. Drill a hole for the center point i\of a size to slip
over your spindle. Print out the drawing, cut out the center hole for
the spindle, and glue it to your indexing disk using the lathe
spindle to center the drawing on the plate when gluing.

Now, turn the disk round to match the outside of your drawing that has
been glued to it. Then take the disk to the bandsaw and make cuts on
each of the 96 segment edges. Make a deeper cut on every other one to
indicate what is the 48 position slots. If you don't have a bandsaw,
use a hacksaw to saw the slots.

Again, mount the disk on your lathe and make up a mounting for a piece
of a hacksaw blade to swing in and engage the slots in the disk. This
will give you the option of 96 or 48 position indexing, plus a number
of other positions less than 96.

This works much better than trying to get your drill to make a hole
exactly on one of the lines that will always align with a pin
arrangement. I've made them both ways, but found that the slot with a
piece of hacksaw blade works best. For easy attachment of the hacksaw
blade mounting to your lathe headstock, a magnetic base works very
well.

I hope this helps. If you have questions, go to my web site to get my
e-mail address and ask the questions that way.

Fred Holder
http://morewoodturning.net


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On Mon, 10 Nov 2008 14:36:01 -0800 (PST), Fred Holder
wrote:

Thanks for the reply, Fred. I did get a wheel made on the drill press
and it works fine for my purposes, but the next one I make I'll try
this way!

Hello John,

I didn't see this message until today. Now, I'm sure that I need to
get another way to read the newsgroup.

In relation to your question, I've made a number of indexing wheels
over the years. The easiest way is to use Woodturner PRO or one of the
other segmenting projects. Select a ring diameter that will print onto
an 8-1/2 x 11 inch page. Set the center diameter to the diameter of
your lathe spindle; i.e. 1", 1-1/4", etc. Then set the number of
segments to 96. Drill a hole for the center point i\of a size to slip
over your spindle. Print out the drawing, cut out the center hole for
the spindle, and glue it to your indexing disk using the lathe
spindle to center the drawing on the plate when gluing.

Now, turn the disk round to match the outside of your drawing that has
been glued to it. Then take the disk to the bandsaw and make cuts on
each of the 96 segment edges. Make a deeper cut on every other one to
indicate what is the 48 position slots. If you don't have a bandsaw,
use a hacksaw to saw the slots.

Again, mount the disk on your lathe and make up a mounting for a piece
of a hacksaw blade to swing in and engage the slots in the disk. This
will give you the option of 96 or 48 position indexing, plus a number
of other positions less than 96.

This works much better than trying to get your drill to make a hole
exactly on one of the lines that will always align with a pin
arrangement. I've made them both ways, but found that the slot with a
piece of hacksaw blade works best. For easy attachment of the hacksaw
blade mounting to your lathe headstock, a magnetic base works very
well.

I hope this helps. If you have questions, go to my web site to get my
e-mail address and ask the questions that way.

Fred Holder
http://morewoodturning.net

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