I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

"Ignoramus8473" wrote in message
...
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

For a lot of the mini mills they have prefab cabinets available. Acrylic is
supposedly more scratch resistant, but if you think you might have a cutter
break and fly off the mill several hundred feet per second Lexan will stop
it without cracking. I have never had the pieces of a broken cutter go
flying, but you never know, and I have not been milling all that long. I
suspect most home built cabinets are made with whatever the builder was able
to find at Home Depot.

On Jul 24, 10:43*am, Ignoramus8473
wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

defiantly $LEXAN$

On Jul 24, 8:43*am, Ignoramus8473
wrote:
I wanted to make a guard around the milling table

My first question is what material to use? Acrylic? Lexan?

Lexan :== Tuffak :== polycarbonate is shatter resistant
Acrylic:== plexiglas :== Lucite is less so, but less expensive.

I'd be somewhat concerned with compatibility with your
cutting lubricant, as well; neither will do well with trichlor.

Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

I just put up a page on my own take on a coolant shield. It is
decidedly low-tech, but works well.
http://jelinux.pico-systems.com/shield.html

Jon

On Jul 24, 10:43*am, Ignoramus8473
wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

I believe I'd make one from tempered hardboard with hinges on the back
corners first, just to see how big of a pain it was going to be to
live with. If you like it you can always make another more permanent
one from plastic or 16ga sheetmetal. The one shown looks to be clear
plastic and also looks like it will constantly be in the way on a
manual machine

whit3rd wrote:
Lexan :== Tuffak :== polycarbonate is shatter resistant
Acrylic:== plexiglas :== Lucite is less so, but less expensive.

I'd be somewhat concerned with compatibility with your
cutting lubricant, as well; neither will do well with trichlor.

I can't imagine anybody using trichloroethane today. Acrylic -
Plexiglas - seems to handle oil and typical coolants just fine.

Jon

On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

When I was first learning CNC, I fast moved a workpiece though a
solid carbide end mill -- and spent the next eternity ducking it
bouncing off hard plaster walls. :-)

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 2010-07-24, Jon Elson wrote:
whit3rd wrote:
Lexan :== Tuffak :== polycarbonate is shatter resistant
Acrylic:== plexiglas :== Lucite is less so, but less expensive.

I'd be somewhat concerned with compatibility with your
cutting lubricant, as well; neither will do well with trichlor.

I can't imagine anybody using trichloroethane today.

IIRC, the original formula of TapMagic still has it, and you can
(by jumping through hoops) still get it.

But you are not going to be spraying it around on a CNC mill
anyway. :-)

Acrylic -
Plexiglas - seems to handle oil and typical coolants just fine.

Yes -- but given the application I would not want it because it
is so much more brittle.

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 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

When I was first learning CNC, I fast moved a workpiece though a
solid carbide end mill -- and spent the next eternity ducking it
bouncing off hard plaster walls. :-)

Yea, that's fun, I had this experience at 15 when I crashed a lathe
carriage into the chuck. The lathe was 10 kW, like this one:

http://uaprom-image.s3.amazonaws.com...0_dsc07722.jpg

i

"Ignoramus8473" wrote in message
...
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

AIR, acrylic has better clarity than polycarbonate. The Tormach CNC mill
uses 3/16" acrylic guards and that has worked fine for me over the past 3
years. A word of warning though - plan on higher guards than those in your
referenced picture if you plan to use coolant with face mills, flycutters,
or other large diameter cutters. They really fling the coolant around.

Mike

Mike Henry wrote:


AIR, acrylic has better clarity than polycarbonate. The Tormach CNC
mill uses 3/16" acrylic guards and that has worked fine for me over
the past 3 years. A word of warning though - plan on higher guards
than those in your referenced picture if you plan to use coolant with
face mills, flycutters, or other large diameter cutters. They really
fling the coolant around.
Something that has occurred to me, but I haven't implemented it yet, is
to put a lip on the top edge of the shield. What I have now tends to
bounce some of the chips/spray over the shield. An inward-facing lip at
the top might deflect those chips to stay inside the shield. Major
flying tools might be able to break 1/4" Plexiglas, but that would
absorb the energy of the projectile. We are not talking about bullets,
here!

Jon

"Jon Elson" wrote in message
...
Mike Henry wrote:


AIR, acrylic has better clarity than polycarbonate. The Tormach CNC mill
uses 3/16" acrylic guards and that has worked fine for me over the past 3
years. A word of warning though - plan on higher guards than those in
your referenced picture if you plan to use coolant with face mills,
flycutters, or other large diameter cutters. They really fling the
coolant around.
Something that has occurred to me, but I haven't implemented it yet, is to
put a lip on the top edge of the shield. What I have now tends to bounce
some of the chips/spray over the shield. An inward-facing lip at the top
might deflect those chips to stay inside the shield. Major flying tools
might be able to break 1/4" Plexiglas, but that would absorb the energy of
the projectile. We are not talking about bullets, here!
Jon

As an aside, at IMTS-2000, I think, a machining center was demonstrating a
cutter turning at around 15,000 rpm (CAT-40, IIRC). One came loose and went
flying out into the crowd, missed the people, but hit another machine and
bent the sheet metal enclosure like it had been hit by a truck. g

--
Ed Huntress

"Ignoramus8473" wrote in message
...
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" Lexan will return .22 mag bullets from a revolver w/ a 6 1/4" barrel.
We tried it on an old smoky Jeep windshield when we replaced it with a new
panel years ago. I suspect that is more energy than a broken cutter.

On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

When I was first learning CNC, I fast moved a workpiece though a
solid carbide end mill -- and spent the next eternity ducking it
bouncing off hard plaster walls. :-)

Yea, that's fun, I had this experience at 15 when I crashed a lathe
carriage into the chuck. The lathe was 10 kW, like this one:

http://uaprom-image.s3.amazonaws.com...0_dsc07722.jpg

Looks like a nice machine.

Must have felt really bad at 15 to crash that.

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 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

When I was first learning CNC, I fast moved a workpiece though a
solid carbide end mill -- and spent the next eternity ducking it
bouncing off hard plaster walls. :-)

Yea, that's fun, I had this experience at 15 when I crashed a lathe
carriage into the chuck. The lathe was 10 kW, like this one:

http://uaprom-image.s3.amazonaws.com...0_dsc07722.jpg

Looks like a nice machine.

Must have felt really bad at 15 to crash that.

It still feels bad.

i

On Mon, 26 Jul 2010 03:58:31 +0000, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:

I wanted to make a guard around the milling table, so that
chips and coolant would not be strewn all over the shop
[like]
http://machineability.com/Bridgeport_series_II.html
My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or
carbide mill half), you want something more likely to keep it
away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like
what is used to bulletproof the tellers at some banks. :-)
....

With thicker plastic, it probably would make sense to add a thin
easily-replaceable layer on the inside, using eg 1/16" acrylic,
which is available inexpensively at many local hardware stores.

--
jiw

In article ,
Ignoramus1880 wrote:

On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain will work to
catch spay and chips, and will stop a flying cutter by deflecting. These are
not bullets.

For the record, the Flexbar guard on my lathe is made of 3/16" thick lexan, and
the backshield (which I made) is a sheet of 1/8" plexiglass hanging from the
Flexbar's axle.

As for height above the cutting point, whatever is needed to make the edge at
least 45 degrees angle from wherever the chips and spray come from will catch
most of it. But you will not get all of it unless there is complete enclosure.
Bottom line is to make things easily adjustable, so you can adapt to various
setups.

Joe Gwinn

On 2010-07-26, Joseph Gwinn wrote:
In article ,
Ignoramus1880 wrote:

On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain
will work to catch spay and chips, and will stop a flying cutter by
deflecting. These are not bullets.

I agree, but I think that it will be messier.

I may get away with using Luan plywood for rear and sides.

For the record, the Flexbar guard on my lathe is made of 3/16" thick
lexan, and the backshield (which I made) is a sheet of 1/8"
plexiglass hanging from the Flexbar's axle.

That would certainly be cheaper.

As for height above the cutting point, whatever is needed to make
the edge at least 45 degrees angle from wherever the chips and spray
come from will catch most of it. But you will not get all of it
unless there is complete enclosure. Bottom line is to make things
easily adjustable, so you can adapt to various setups.

Yeah. I am not losing sleep over this, but if I really use this mill
seriously, a good guard will save a good deal of grief from just
chips, coolant, and other messy stuff.

3/16" ;lexan seems to be completely adequate.

i

On 7/26/2010 8:41 AM, Joseph Gwinn wrote:
In articlestidnfZlGOSbjNDRnZ2dnUVZ_j2dnZ2d@giganews. com,
wrote:

On 2010-07-26, DoN. wrote:
On 2010-07-25, wrote:
On 2010-07-25, DoN. wrote:
On 2010-07-24, wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain will work to
catch spay and chips, and will stop a flying cutter by deflecting. These are
not bullets.

For the record, the Flexbar guard on my lathe is made of 3/16" thick lexan, and
the backshield (which I made) is a sheet of 1/8" plexiglass hanging from the
Flexbar's axle.

As for height above the cutting point, whatever is needed to make the edge at
least 45 degrees angle from wherever the chips and spray come from will catch
most of it. But you will not get all of it unless there is complete enclosure.
Bottom line is to make things easily adjustable, so you can adapt to various
setups.

What size machine is under discussion? I would think that that would
have some relation to the required robustness of the guard.

"Ignoramus2966" wrote in message
...
On 2010-07-26, Joseph Gwinn wrote:
In article ,
Ignoramus1880 wrote:

On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473
wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473
wrote:
I wanted to make a guard around the milling table, so that chips
and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or
carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain
will work to catch spay and chips, and will stop a flying cutter by
deflecting. These are not bullets.

I agree, but I think that it will be messier.

I may get away with using Luan plywood for rear and sides.

For the record, the Flexbar guard on my lathe is made of 3/16" thick
lexan, and the backshield (which I made) is a sheet of 1/8"
plexiglass hanging from the Flexbar's axle.

That would certainly be cheaper.

As for height above the cutting point, whatever is needed to make
the edge at least 45 degrees angle from wherever the chips and spray
come from will catch most of it. But you will not get all of it
unless there is complete enclosure. Bottom line is to make things
easily adjustable, so you can adapt to various setups.

Yeah. I am not losing sleep over this, but if I really use this mill
seriously, a good guard will save a good deal of grief from just
chips, coolant, and other messy stuff.

3/16" ;lexan seems to be completely adequate.

I would certainly think so. How fast does your mill turn?

On 2010-07-26, J. Clarke wrote:
On 7/26/2010 8:41 AM, Joseph Gwinn wrote:
In articlestidnfZlGOSbjNDRnZ2dnUVZ_j2dnZ2d@giganews. com,
wrote:

On 2010-07-26, DoN. wrote:
On 2010-07-25, wrote:
On 2010-07-25, DoN. wrote:
On 2010-07-24, wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain will work to
catch spay and chips, and will stop a flying cutter by deflecting. These are
not bullets.

For the record, the Flexbar guard on my lathe is made of 3/16" thick lexan, and
the backshield (which I made) is a sheet of 1/8" plexiglass hanging from the
Flexbar's axle.

As for height above the cutting point, whatever is needed to make the edge at
least 45 degrees angle from wherever the chips and spray come from will catch
most of it. But you will not get all of it unless there is complete enclosure.
Bottom line is to make things easily adjustable, so you can adapt to various
setups.

What size machine is under discussion? I would think that that would
have some relation to the required robustness of the guard.


2 HP CNC knee mill with 3 HP peak HP (makes it sound like it was sold
by Sears, but the 3 peak HP rating is for up to 30 minutes). Max
spindle speed 4,200 RPM, but I would probably run it under 3,000 RPM.

i

On 2010-07-26, Bob La Londe wrote:
"Ignoramus2966" wrote in message
...
On 2010-07-26, Joseph Gwinn wrote:
In article ,
Ignoramus1880 wrote:

On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473
wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473
wrote:
I wanted to make a guard around the milling table, so that chips
and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or
carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain
will work to catch spay and chips, and will stop a flying cutter by
deflecting. These are not bullets.

I agree, but I think that it will be messier.

I may get away with using Luan plywood for rear and sides.

For the record, the Flexbar guard on my lathe is made of 3/16" thick
lexan, and the backshield (which I made) is a sheet of 1/8"
plexiglass hanging from the Flexbar's axle.

That would certainly be cheaper.

As for height above the cutting point, whatever is needed to make
the edge at least 45 degrees angle from wherever the chips and spray
come from will catch most of it. But you will not get all of it
unless there is complete enclosure. Bottom line is to make things
easily adjustable, so you can adapt to various setups.

Yeah. I am not losing sleep over this, but if I really use this mill
seriously, a good guard will save a good deal of grief from just
chips, coolant, and other messy stuff.

3/16" ;lexan seems to be completely adequate.

I would certainly think so. How fast does your mill turn?



up to 4.2k RPM, but I was told to run it under 3K RPM.

i

In article ,
"J. Clarke" wrote:

On 7/26/2010 8:41 AM, Joseph Gwinn wrote:
In articlestidnfZlGOSbjNDRnZ2dnUVZ_j2dnZ2d@giganews. com,
wrote:

On 2010-07-26, DoN. wrote:
On 2010-07-25, wrote:
On 2010-07-25, DoN. wrote:
On 2010-07-24, wrote:
I wanted to make a guard around the milling table, so that chips and
coolant would not be strewn all over the shop.

I want to make something like what I saw on the web:

http://machineability.com/Bridgeport_series_II.html

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

I think we are going overboard with the guard. A flexible curtain will
work to
catch spay and chips, and will stop a flying cutter by deflecting. These
are
not bullets.

For the record, the Flexbar guard on my lathe is made of 3/16" thick lexan,
and
the backshield (which I made) is a sheet of 1/8" plexiglass hanging from
the
Flexbar's axle.

As for height above the cutting point, whatever is needed to make the edge
at
least 45 degrees angle from wherever the chips and spray come from will
catch
most of it. But you will not get all of it unless there is complete
enclosure.
Bottom line is to make things easily adjustable, so you can adapt to
various
setups.

What size machine is under discussion? I would think that that would
have some relation to the required robustness of the guard.

I have the Flexbar guard on a Clausing 5914 with a ~2 HP motor, and a max speed
of 1900 rpm.

Iggy has posted the details of his mill.

Joe Gwinn

On 2010-07-26, Ignoramus1880 wrote:
On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:

[ ... ]

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

Well ... part of the problem is that a broken cutter can bounce
off the workpiece or the far side guard and angle up to clear the near
side guard.

What I would suggest is perhaps a couple of inches plus a curved
"sneeze guard" mounted over the whole thing (perhaps to the bottom end
of the quill -- or to the headstock casting) and curving down to bounce
things back into the main guard.

How much you really need will be a function of how big your
cutters are and how much you push them. With your machine, you've got
the capability of seriously pushing them.

Good Luck,
DoN.

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On 2010-07-27, DoN. Nichols wrote:
On 2010-07-26, Ignoramus1880 wrote:
On 2010-07-26, DoN. Nichols wrote:
On 2010-07-25, Ignoramus8473 wrote:
On 2010-07-25, DoN. Nichols wrote:
On 2010-07-24, Ignoramus8473 wrote:

[ ... ]

My first question is what material to use? Acrylic? Lexan?

*Thick* Lexan -- not Plexiglass, because that is too brittle.
If you have something heavier than a chip (e.g. a broken HSS or carbide
mill half), you want something more likely to keep it away from you.

1/4 inch?

1/4" or perhaps 5/16" for the size of mill you are using. For
some machines, you would want something 1" thick or so -- like what is
used to bulletproof the tellers at some banks. :-)

How high do you think it should go above the cutting point? I mean, I
am sure that the higher, the better, but at some point the height will
interfere with the ram and table movement. So if I could get some idea
like "4 inches above the point of cutting" it would be nice. Just want
to find a way to think properly about that.

Well ... part of the problem is that a broken cutter can bounce
off the workpiece or the far side guard and angle up to clear the near
side guard.

But it would lose a lot of energy this way.

Anyway, my main reason for having a guard, is to keep chips and
coolant inside the table.

What I would suggest is perhaps a couple of inches plus a curved
"sneeze guard" mounted over the whole thing (perhaps to the bottom end
of the quill -- or to the headstock casting) and curving down to bounce
things back into the main guard.

How much you really need will be a function of how big your
cutters are and how much you push them. With your machine, you've got
the capability of seriously pushing them.

DoN, think keeping chips and splashing coolant inside.

i