I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw. I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White

In article ,
Doug White wrote:

I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw. I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White

It's been quite a few years (I did a lot of round plexiglas things back
in my lab-rat days), but either a sharp holesaw or a flycutter, either
one run slow enough and/or with enough air to keep it cool to limit
chip-melting, might be worth a shot.

Then again, a coping saw or jewelers saw would let you control cut speed
to a fair thee well and might get the job done as well or better than
the bandsaw would. Generally backside roughness == melted and re-welded
chips.

For thin stock shears or tinsnips might work, nipping the corners off -
at some point (of thickness) they stop cutting and start shattering,
though.

--
Cats, coffee, chocolate...vices to live by

"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw. I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White


Score both sides with a utility knife and snap off with a pliers.

On 2011-04-08, Doug White wrote:
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw.

Hmm ... I think that 2-56 would not be strong enough for even a
short stack. What I would do is get a replaceable tip tailstock live
center, and make a tip with a center hole for it which would slide over
the center rod and clamp the stack firmly in place. I've used a
variation on this to turn new crystals for dial indicators. Once your
workpieces are big enough in diameter, you can make a pusher plate with
a center countersink drilled hole and a standard live center. I did
this with Lexan instead of Plexiglass, because I wanted it to be
flexible to take the dome for the crystal.

If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

How much oversized do you plan to make the pieces? You know
that Plexiglass breaks cleanly when bent at a score line. This could
use a grid of lines to break into squares, or lines at 120 degree angles
to break into triangles and get a cleaner edge before turning. (And
yes, I have used a sheet metal brake to do the bending along the scribe
when a piece was too small to grip easily.) You can also use a
combination of a milling vise (smooth jaws) and a broad-jawed Vise Grip
to do it with smaller pieces.

And avoid getting oil on the Plexiglass -- or many other
solvents for that matter. They cause it to disintegrate into a bunch of
cracked pieces.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw.

Avoid the saw. Scribe and break. (Won't work on my Lexan, but
great on Plexiglass.)

I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

It would almost certainly.

Any other tricks or suggestions?

Mine above.

Enjoy,
DoN.

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

On Apr 7, 8:16*pm, Doug White wrote:
I need to make some clear front sight apertures for my target rifle. *
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. *The commercial ones are
getting scarce, especially in the sizes I need. *The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. *If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. *What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. *I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. *It might also be time to put a new blade on the saw. *I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White

This came up once before, my advice is the same, make a punch and die,
should work well with thin stock. Undoubtedly the way the commercial
ones are made. Wouldn't take long to bore an oblong block of steel,
then slot it, die block and punch guide all in one. If you need a
concentric hole, a simple jig with a bushing would let you drill a
centered pilot hole, then open it up with a clock reamer to whatever
you want. A Sat. afternoon project. Most likely the originals were
from acetate sheet which punches better.

Stan

"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw. I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White


You can buy a 12" long piece of 7/8" round cast acrylic for $4 and turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

On Apr 7, 7:16*pm, Doug White wrote:
I need to make some clear front sight apertures for my target rifle. *

Any other tricks or suggestions?

Hi Doug,

What material?

How thick?

Tolerance on diameter?

How many?

I have a 35 Watt CO2 laser I built that could cut the disks perfectly.
You would have to then machine the inner hole. You could also ask at a
local engraving shop that has a laser.

Email me if you like.

Dave

"Dave, I can't do that" wrote in news:5d40b33a-
:

On Apr 7, 7:16*pm, Doug White wrote:
I need to make some clear front sight apertures for my target rifle. *

Any other tricks or suggestions?

Hi Doug,

What material?

How thick?

Tolerance on diameter?

How many?

I have a 35 Watt CO2 laser I built that could cut the disks perfectly.
You would have to then machine the inner hole. You could also ask at a
local engraving shop that has a laser.

Email me if you like.

It's acrylic, rougly 0.10" thick. The tolerances on the final diameter
are pretty tight, but slightly oversized blanks with a small center hole
would save a lot of work. I assume the laser cuts cleanly enough that
there wouldn't be optical distortion in the plastic after the fact?

Doug White

"David Courtney" wrote in
:


"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small
black ring when mounted in a hooded sight tube. The commercial ones
are getting scarce, especially in the sizes I need. The OD is ~
0.86", and the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should
be able to turn them to size fairly easily. What I'm wondering about
is the best way to cut out the rough blanks without raising a burr or
making a mess out of the protective plastic/paper film on the back
side. I'd planned on using my bandsaw, but my experience is that the
back of plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get
a cleaner cut. It might also be time to put a new blade on the saw.
I thought about sticking the plastic down with double stick, but I
suspect the protective film would come off when I try to remove the
backer.

Any other tricks or suggestions?

Thanks!

Doug White


You can buy a 12" long piece of 7/8" round cast acrylic for $4 and
turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

These need to be pretty optically flat & clear. At least to the point
where images are not distorted looking through the result. I'm not sure
how I could achieve that easily. The raw material I have is mil-spec
aircraft window grade cast acrylic.

Doug White

wrote in news:99100af4-0eac-4317-a37e-432a8b18f153
@f18g2000yqd.googlegroups.com:

On Apr 7, 8:16*pm, Doug White wrote:
I need to make some clear front sight apertures for my target rifle. *
These have a conical hole bored in the center, which makes a small
black
ring when mounted in a hooded sight tube. *The commercial ones are
getting scarce, especially in the sizes I need. *The OD is ~ 0.86",
and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. *If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. *What I'm wondering about is
t
he
best way to cut out the rough blanks without raising a burr or making
a
mess out of the protective plastic/paper film on the back side. *I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get
a
cleaner cut. *It might also be time to put a new blade on the saw. *I
thought about sticking the plastic down with double stick, but I
suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White

This came up once before, my advice is the same, make a punch and die,
should work well with thin stock. Undoubtedly the way the commercial
ones are made. Wouldn't take long to bore an oblong block of steel,
then slot it, die block and punch guide all in one. If you need a
concentric hole, a simple jig with a bushing would let you drill a
centered pilot hole, then open it up with a clock reamer to whatever
you want. A Sat. afternoon project. Most likely the originals were
from acetate sheet which punches better.

They are made from 3mm thick aircraft window grade acrylic. Making a
punch (assuming it didn't just shatter the things) is probably a lot more
effort than making a half dozen or so by hand on the lathe.

Doug White

"DoN. Nichols" wrote in
:

On 2011-04-08, Doug White wrote:
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small
black ring when mounted in a hooded sight tube. The commercial ones
are getting scarce, especially in the sizes I need. The OD is ~
0.86", and the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw.

Hmm ... I think that 2-56 would not be strong enough for even a
short stack. What I would do is get a replaceable tip tailstock live
center, and make a tip with a center hole for it which would slide
over the center rod and clamp the stack firmly in place. I've used a
variation on this to turn new crystals for dial indicators. Once your
workpieces are big enough in diameter, you can make a pusher plate
with a center countersink drilled hole and a standard live center. I
did this with Lexan instead of Plexiglass, because I wanted it to be
flexible to take the dome for the crystal.

If I can cut them into rough octagons, I should
be
able to turn them to size fairly easily. What I'm wondering about is
the best way to cut out the rough blanks without raising a burr or
making a mess out of the protective plastic/paper film on the back
side. I'd planned on using my bandsaw, but my experience is that the
back of plastic cut on it is pretty rough.

How much oversized do you plan to make the pieces? You know
that Plexiglass breaks cleanly when bent at a score line. This could
use a grid of lines to break into squares, or lines at 120 degree
angles to break into triangles and get a cleaner edge before turning.
(And yes, I have used a sheet metal brake to do the bending along the
scribe when a piece was too small to grip easily.) You can also use a
combination of a milling vise (smooth jaws) and a broad-jawed Vise
Grip to do it with smaller pieces.

And avoid getting oil on the Plexiglass -- or many other
solvents for that matter. They cause it to disintegrate into a bunch
of cracked pieces.

I was thinking I could back up the plastic with scrap masonite to get
a cleaner cut. It might also be time to put a new blade on the saw.

Avoid the saw. Scribe and break. (Won't work on my Lexan, but
great on Plexiglass.)

I
thought about sticking the plastic down with double stick, but I
suspect the protective film would come off when I try to remove the
backer.

It would almost certainly.

Any other tricks or suggestions?

Mine above.

Thanks! I'll try score & break. That should get me to squares, and I
can just bide my time & turn those.

I agree, the 2-56 will flex if I stack more than a couple. I've been
planning on supporting the other end with the tailstock & a center. For
the first one or two, I will probably do them individually to work out
feeds & speeds. I've got league matches starting in two weeks, and I'd
really like to have a slightly smaller aperture than I have now.

My biggest problem at the moment is that the target "black" looks dark
grey at 200 yards. I don't know if it's my prescription, dust in my rear
sight or the beginnings of cataracts. I'm about to give my rear sight a
thorough going over & hope I'm being tormented by a spec of lint in just
the wrong place.

Doug White

Doug White wrote:

"Dave, I can't do that" wrote in news:5d40b33a-
:

On Apr 7, 7:16 pm, Doug White wrote:
I need to make some clear front sight apertures for my target rifle.

Any other tricks or suggestions?

Hi Doug,

What material?

How thick?

Tolerance on diameter?

How many?

I have a 35 Watt CO2 laser I built that could cut the disks perfectly.
You would have to then machine the inner hole. You could also ask at a
local engraving shop that has a laser.

Email me if you like.

It's acrylic, rougly 0.10" thick. The tolerances on the final diameter
are pretty tight, but slightly oversized blanks with a small center hole
would save a lot of work. I assume the laser cuts cleanly enough that
there wouldn't be optical distortion in the plastic after the fact?

Doug White

These folks do custom laser cutting of acrylic and other materials:

http://www.pololu.com/catalog/product/749

On 4/7/2011 10:16 PM, Doug White wrote:
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should be
able to turn them to size fairly easily. What I'm wondering about is the
best way to cut out the rough blanks without raising a burr or making a
mess out of the protective plastic/paper film on the back side. I'd
planned on using my bandsaw, but my experience is that the back of
plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get a
cleaner cut. It might also be time to put a new blade on the saw. I
thought about sticking the plastic down with double stick, but I suspect
the protective film would come off when I try to remove the backer.

Any other tricks or suggestions?

Thanks!

Doug White


I though about making plastic apertures. I decided it was going to be
very difficult because of the precision required in the bevel of the
hole, that is what you see when you look through it and it must be perfect.

I went to using an adjustable front aperture. I just looked at the
current prices. Wow!

Champion shooters supply has the plastic apertures for $6.00.

http://www.championshooters.com/stor...cat=332&page=1

Champion’s choice probably has them.

Doug White wrote:
"David Courtney" wrote in
"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small
black ring when mounted in a hooded sight tube. The commercial ones
are getting scarce, especially in the sizes I need. The OD is ~
0.86", and the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw. If I can cut them into rough octagons, I should
be able to turn them to size fairly easily. What I'm wondering about
is the best way to cut out the rough blanks without raising a burr or
making a mess out of the protective plastic/paper film on the back
side. I'd planned on using my bandsaw, but my experience is that the
back of plastic cut on it is pretty rough.

I was thinking I could back up the plastic with scrap masonite to get
a cleaner cut. It might also be time to put a new blade on the saw.
I thought about sticking the plastic down with double stick, but I
suspect the protective film would come off when I try to remove the
backer.

Any other tricks or suggestions?

You can buy a 12" long piece of 7/8" round cast acrylic for $4 and
turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

These need to be pretty optically flat & clear. At least to the point
where images are not distorted looking through the result. I'm not sure
how I could achieve that easily. The raw material I have is mil-spec
aircraft window grade cast acrylic.

What's the spec on the center hole? I once made a bunch of plastic washers
in acrylic by sliding some blanks onto a bolt, clamping them together with
a nut, chucking the bolt into a hand drill, and "grinding" them to size on
the belt sander. But these were 1/4" thick, and the center hole was 1/4".

Good Luck!
Rich

Hi Doug,

The laser can easily hold 0.005" The edge looks like flame finishing.
There is no obvious distortion visible on stuff I have done as the
laser dot size is only 0.006" diameter and at that thickness, little-
to-no Kerf. Cast acrylic is good for clean cuts, extruded is not so
good. There may be a small amount of distortion within about 1/32" of
the cut edge but I am sure that would not matter.

I think I have some 1/16" here and if you want to Email a postal
address I'll send you some samples. Is the 0.860" a max or min? Give
me the tolerance. I think I have some in fluorescent orange and green
too. Might be fun to try.

Dave

On 2011-04-08, David Courtney wrote:

"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

[ ... ]

You can buy a 12" long piece of 7/8" round cast acrylic for $4 and turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

Can *you* part it to give a clear transparent finish? He needs
to be able to see through this, except where the tapered hole is for
contrast.

If you faced it with PCD (Poly Crystalline Diamond) you *might*
be able to get a nice enough finish on one side -- but you then need to
be able to flip it over and hold it parallel to face the other side.
With a Jeweler's lathe, perhaps some step collets could be used for
holding the disc.

Enjoy,
DoN.

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

On 2011-04-08, Doug White wrote:
"DoN. Nichols" wrote in
:

On 2011-04-08, Doug White wrote:
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small
black ring when mounted in a hooded sight tube. The commercial ones
are getting scarce, especially in the sizes I need. The OD is ~
0.86", and the inner hole will go down as small as 0.095"

I'd like to turn the OD on a short stack of blanks bolted to an arbor
with a 2-56 screw.

Hmm ... I think that 2-56 would not be strong enough for even a
short stack. What I would do is get a replaceable tip tailstock live

[ ... ]

Avoid the saw. Scribe and break. (Won't work on my Lexan, but
great on Plexiglass.)

[ ... ]

Thanks! I'll try score & break. That should get me to squares, and I
can just bide my time & turn those.

Indeed so.

I agree, the 2-56 will flex if I stack more than a couple. I've been
planning on supporting the other end with the tailstock & a center. For
the first one or two, I will probably do them individually to work out
feeds & speeds. I've got league matches starting in two weeks, and I'd
really like to have a slightly smaller aperture than I have now.

O.K.

BTW -- in my dial crystals, I can't have a hole in the center at all.
What I did to maximize the drive at about 2-1/4" diameter was to
recess all but about the outer 1/8" or so on both the backing
piece in the chuck and the pusher plate which the live center
was engaging so the entire pressure was applied near the OD for
maximum torque transmission. (If you clamp with a nut, the
pressure is at too small a radius, and the workpieces are more
likely to slip. With the near-OD clamping, I could handle
something like eight or ten workpieces at once. But approach
the maximum extension of corners carefully. :-)

My biggest problem at the moment is that the target "black" looks dark
grey at 200 yards. I don't know if it's my prescription, dust in my rear
sight or the beginnings of cataracts. I'm about to give my rear sight a
thorough going over & hope I'm being tormented by a spec of lint in just
the wrong place.

Hmm ... perhaps diffraction from the smaller aperture? That may
be why they are not made smaller?

Good Luck,
DoN.

P.S. Wish that I had known about the target shooting at the "Toot"
when I was there. :-)

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

On Apr 8, 4:04*pm, "Dave, I can't do that"
wrote:

I think I have some 1/16" here and if you want to Email a postal
address

Oooops, offer retracted, well at least temporarily anyway. Laser would
not fire this morning. Not a good sign after going through all the
procedures, it looks like a tickle pulse problem as I can get it to
fire on full power, but not on adjustable pulse rate. Technology
designed to keep one's retirement busy.

Dave

"DoN. Nichols" wrote in message
...
On 2011-04-08, David Courtney wrote:

"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.
These have a conical hole bored in the center, which makes a small black
ring when mounted in a hooded sight tube. The commercial ones are
getting scarce, especially in the sizes I need. The OD is ~ 0.86", and
the inner hole will go down as small as 0.095"

[ ... ]

You can buy a 12" long piece of 7/8" round cast acrylic for $4 and
turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

Can *you* part it to give a clear transparent finish? He needs
to be able to see through this, except where the tapered hole is for
contrast.

-snip nonsense-

Yes, *I* can but that doesn't necessarily mean that *you* could.

On 2011-04-09, David Courtney wrote:

"DoN. Nichols" wrote in message
...
On 2011-04-08, David Courtney wrote:

"Doug White" wrote in message
. ..
I need to make some clear front sight apertures for my target rifle.

[ ... ]

You can buy a 12" long piece of 7/8" round cast acrylic for $4 and
turn
it to size before you part off the thickness you need:
http://www.usplastic.com/catalog/ite...0787&catid=440

Can *you* part it to give a clear transparent finish? He needs
to be able to see through this, except where the tapered hole is for
contrast.

-snip nonsense-

Yes, *I* can but that doesn't necessarily mean that *you* could.

So -- if not for my enlightenment, perhaps for the OP's
enlightenment, would you care to detail how he could do it. My snipped
(by you) "nonsense" was all that I could think of for doing it, but I
have not tried it. I do know that PCD on a rigide enough machine can
produce an optical finish on aluminum, at least.

Enjoy,
DoN.

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