Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
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Gunner
 
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Default Airgun plans?

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
  #2   Report Post  
Posted to rec.crafts.metalworking
 
Posts: n/a
Default Airgun plans?

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?

Knowing the internet someone, somewhere, has probably tried this
already.

For air rifles good literature is available in England. Why not try the
British model discussion group?

Wolfgang

  #3   Report Post  
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Don Foreman
 
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Default Airgun plans?

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

I'm contemplating a *low energy* golfball cannon suitable for
decimating squirrel nests in a residential neighborhood. No plans
yet. There's a clear field of fire for a good 300 feet to the south,
with a 20' freeway sound wall behind it. I'm thinking max
altitude of maybe 200 feet, which is about 10 joules of muzzle energy
with a golfball.

DIL Sherri would probably use an AA12 FA shotgun if she had access
to one -- she's that mad at the treerats. SIL is a more temperate
voice.....
  #4   Report Post  
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Trevor Jones
 
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Default Airgun plans?

http://www.bryanandac.com/new_page_10.htm

http://www.hegmans.de/theo/neu_1.htm

There's a couple sites for inspiration, if not any actual plans. have
been interested in airguns for a very long time, and plans seem to be
almost nonexistant.

There are a couple forums out there that have a lot of knowlegable
scratch builders. The one on Delphi under the name of BullDurham is
probably the best that I know of. Do a google for fun supply forum or
try yellowforum.com and pull down the menu at the top of the page.

The only set of actual plans that I am aware of is a book published in
Britain with the title Building a Modern Airgun or something simlar to
that, that covers the complete build of a pre charged pneumatic (PCP)
airgun. I did a ggogle search and was unable to find it right off, but
IIRC it was mentioned in the gunsmithing forum on the chaski forums a
while back.

There are a couple other books out there that detail the building of
Girandoni replicas, and air canes, but they are more along the lines of
historical replicas than a modern airgun.

Cheers
Trevor Jones
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Trevor Jones
 
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Default Airgun plans?

Trevor Jones wrote:

http://www.bryanandac.com/new_page_10.htm

http://www.hegmans.de/theo/neu_1.htm

There's a couple sites for inspiration, if not any actual plans. have
been interested in airguns for a very long time, and plans seem to be
almost nonexistant.

There are a couple forums out there that have a lot of knowlegable
scratch builders. The one on Delphi under the name of BullDurham is
probably the best that I know of. Do a google for fun supply forum or
try yellowforum.com and pull down the menu at the top of the page.

The only set of actual plans that I am aware of is a book published in
Britain with the title Building a Modern Airgun or something simlar to
that, that covers the complete build of a pre charged pneumatic (PCP)
airgun. I did a ggogle search and was unable to find it right off, but
IIRC it was mentioned in the gunsmithing forum on the chaski forums a
while back.

There are a couple other books out there that detail the building of
Girandoni replicas, and air canes, but they are more along the lines of
historical replicas than a modern airgun.

Cheers
Trevor Jones


Awright. Not the Chaski forums, but practicalmachinist.com, where I
found....
quote
If you are interested in building a pneumatic airgun, the book you want
to get is "The Modern Pneumatic Airgun" by H.M. Buckley. It is
self-published in the UK and very hard to come by in the states. I
ordered my copy from , which takes credit card
orders from the USA. I haven't started on the project, but the book is
almost 200 pages of high quality, detailed instructions and drawings.
unquote

Cheers
Trevor Jones


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Christopher Tidy
 
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Default Airgun plans?

I think you'll like this guy's site:
http://www.sentex.net/~mwandel/cannon/cannon.html

Click on the link which says "Building my own air gun".

Chris

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Gunner
 
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Default Airgun plans?

On Sun, 23 Apr 2006 11:47:52 -0600, Trevor Jones
wrote:

Trevor Jones wrote:

http://www.bryanandac.com/new_page_10.htm

http://www.hegmans.de/theo/neu_1.htm

There's a couple sites for inspiration, if not any actual plans. have
been interested in airguns for a very long time, and plans seem to be
almost nonexistant.

There are a couple forums out there that have a lot of knowlegable
scratch builders. The one on Delphi under the name of BullDurham is
probably the best that I know of. Do a google for fun supply forum or
try yellowforum.com and pull down the menu at the top of the page.

The only set of actual plans that I am aware of is a book published in
Britain with the title Building a Modern Airgun or something simlar to
that, that covers the complete build of a pre charged pneumatic (PCP)
airgun. I did a ggogle search and was unable to find it right off, but
IIRC it was mentioned in the gunsmithing forum on the chaski forums a
while back.

There are a couple other books out there that detail the building of
Girandoni replicas, and air canes, but they are more along the lines of
historical replicas than a modern airgun.

Cheers
Trevor Jones


Awright. Not the Chaski forums, but practicalmachinist.com, where I
found....
quote
If you are interested in building a pneumatic airgun, the book you want
to get is "The Modern Pneumatic Airgun" by H.M. Buckley. It is
self-published in the UK and very hard to come by in the states. I
ordered my copy from , which takes credit card
orders from the USA. I haven't started on the project, but the book is
almost 200 pages of high quality, detailed instructions and drawings.
unquote

Cheers
Trevor Jones


Thanks for the tip on the book!

Credit card? Whats that?

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
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Gerald Miller
 
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Default Airgun plans?

On Sun, 23 Apr 2006 11:31:31 -0500, Don Foreman
wrote:

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

I'm contemplating a *low energy* golfball cannon suitable for
decimating squirrel nests in a residential neighborhood. No plans
yet. There's a clear field of fire for a good 300 feet to the south,
with a 20' freeway sound wall behind it. I'm thinking max
altitude of maybe 200 feet, which is about 10 joules of muzzle energy
with a golfball.

DIL Sherri would probably use an AA12 FA shotgun if she had access
to one -- she's that mad at the treerats. SIL is a more temperate
voice.....

I use small ice cubes in a sling shot to discourage the sh*tty cats
around here - no direct hits yet but tin sheds make a fair noise when
struck by a piece of hard water, sufficient that as soon as I appear,
there is a mad scramble under the hedge.
Gerry :-)}
London, Canada
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Richard J Kinch
 
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Default Airgun plans?

Christopher Tidy writes:

http://www.sentex.net/~mwandel/cannon/cannon.html


Pressure vessels out of ABS pipe? Foolish.


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Don Foreman
 
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Default Airgun plans?

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:

On 23 Apr 2006 09:08:19 -0700, wrote:

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?


Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.


I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....
  #12   Report Post  
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Gunner
 
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Default Airgun plans?

On Mon, 24 Apr 2006 01:47:41 -0500, Don Foreman
wrote:

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:

On 23 Apr 2006 09:08:19 -0700, wrote:

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?


Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.


I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....



You figure the circuitry out..Ill build the Steamgun. Stainless steel
of course. The water injection/volume control sounds a bit interesting
to figure out..but if a steam engine can do it...

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
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Stealth Pilot
 
Posts: n/a
Default Airgun plans?

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner


this is an interesting project.
I've been trying to accumulate enough scrap to make one for some time.
still working on it. damn the chinese! there are no scrap merchants
left in my neck of the woods who arent a siphon for material to china
these days. ...anyway.

there are two schools of thought regarding air rifles. the predominant
school says that the gun must be heavy to make use of it's inertia for
stability. I think that that is erroneous myself and I have won
against the most expensive guns using a much battered club .177 air
rifle. it is a a comparatively light rifle, the Sharp Innova made in
japan. it is not a break back so the sighting on the barrel remains
accurate. on the club ones an old martini henry ww1 rifle adjustable
rear sight was fitted which was superb. (the kids just remembered
their traverse and elevation settings and could pick the rifle up
after someone else and be back shooting in a moment)

The mechanism of this rifle is superb, very simple, and I originally
though would be easy to make. (I'm sure it is if you amass the right
materials.)
I had a chance to measure one and from this I have an incomplete
sketch that I will attempt to upload to the drop box later tonight.

the barrel is in brass, 9.4mm (.37")od with a bore of .177" or 4.5mm
thereabouts. it sits in a larger protective tube made in light steel
which can become a little battered in use without affecting the barrel
accuracy at all. the barrel sits about 5 - 10 mm proud of a parallel
tube that contains the air pump and receiver. a short tube extends
from the barrel down to the receiver. the tube is screwed into the
barrel but just sits pressed to the outer surface of the receiver with
an o ring making the seal. the aft end of the barrel is sealed by a
bolt action which has a tapered pin extending from it to engage and
align the rear of the air pellet.when home the bolt seals the barrel
rear with a very small chamber formed behind the pellet. a 4mm dia
hole extends from this chamber down to the receiver through the
interconnecting tube.

(I never recorded barrel lengths because I was after a shorter action)

the air pump sits below the barrel. it is formed in a steel tube of
22mm od and 19mm id. at the foresight end and hanging down vertically
when about ready to commence compression is a hinged lever. 4 1/4
inches from the hinge fulcrum is a joint to a short lever that returns
back to the piston mechanism and actually drives this through a slot
in the underside of the tube. the piston mechanism is just two pistons
interconnected by a screw adjustable rod, the front piston has a slot
machined in it which accepts the short driving lever, using a roll pin
as the joining pivot. the actual pumping piston is in brass with an
oiled bucket seal on the end.(I think it was leather) the pumping
stroke is 4 1/4 inches.
when this lever is pulled fully back it engages a detent which holds
it against the barrel. in the detent position the air piston is fully
home against the front face of the air receiver.

the air receiver is a 19mm dia cylindrical brass piece, it is sealed
to the pumping tube by a small o ring about a millimeter back from the
front end. the front end has a conical face. this is sized so that the
centre of the piston can sit almost hard up to it and it provides a
small space for the bucket seal to sit without being crushed.
in the centre is a small hole leading back into a chamber of maybe
3/8" dia. the front is sealed by a spring loaded ball. the compression
of the piston unseating this ball to allow compressed gas back into
the receiver. the complete receiver is 55mm long with about the rear
15mm taken up by the firing mechanism. the receiver chamber is
probably 3/8 or so by maybe 30mm. (i never fully disassembled it)

the rear of the receiver is a screw in piece, 19mm dia by 14mm thick
with a 10-15mm nose piece protruding from it. this nose piece is
threaded and screws into the back of the receiver chamber.
through this piece is a polished/reamed 4mm dia hole. in the centre of
this tube section there a 3 o rings sitting side by side to seal the
pin. 10mm forward of the back face of this 14mm piece there is a
transverse 4mm dia hole leading up to the interconnecting tube from
the barrel.

the air control pin is 45mm long and basically is a 4mm dia polished
rod with a 7mm dia land 2.5mm thick sited back 17mm from the leading
end. forward of this land the pin engages precisely into the rear of
the receiver and is sealed by the o rings just forward of the
transverse interconnecting hole. I cant recall what locates the
receiver but I think it was a 6mm dia socket head capscrew up from the
underside into the rear piece which may have been steel.

a 16.5mm od washer 2 mm thick sits against the rear of the 7mm dia
land on the firing pin. behind this is a spring, 9mm dia in .54mm
spring wire.

right at the rear of the piston tube is an internal thread. screwed
into this is a 4mm blanking plate which has a 4mm hole in it to guide
the air control pin. forwqard of this is a hard steel washer 6mm thick
with a 12mm id hole, the purpose of which is to provide a home for the
spring as the air control in drives back, preventing it being crushed.

mounted in the stock immediately behind the pump barrel is the trigger
block. the trigger sits below the trigger block, is pivoted roughly in
its centre axis in profile, with a pawl on the rear edge which pushes
up against the trigger block in turn pushing it up. there is an L
shaped apperture plate which sits flush against the front face of the
trigger block. the L extends back over the top where a spring sits to
push it up from the top of the trigger block.
the apperture plate has a 5mm by 6mm aperture.
the trigger block has a 6mm dia hole back into it with a polyurethane
block at its deepest point.
at rest the apperture plate sits behind the air control pin and blocks
its rearward movement. the hole in the trigger block sits below the
pin axis and so provides a second safety.

when the air pump is used the pressurisation pushes the pin back
against the apperture plate, but all remains sealed at this point. in
competition shooting on a 10m range 2 pumps are sufficient. it can
take up to 11 pumps.

when the trigger is eased back the trigger block is pushed upward
moving the 6mm hole into position to receive the pin, the apperture
plate stays still with the up spring being compressed. as the trigger
pressure is increased the apperture plate is lifted until it
disengages the pin. pressure fires the pin back, collecting the 16mm
washer and return spring, at its rearward travel the polyurethane
block decelerates the pin to a standstill. while this is happening the
air rushes back with the pin, turns up through the 4mm hole and fills
the small aperture behind the pellet driving it forward.
with the pressure gone the return spring pushes the air control pin
back to its forward position and gravity drops the trigger block back
into position. the trigger block is steel, 21 x 9 x 14mm in size. the
apperture L plate is 2.5mm thich hardened steel.

ok? hopefully that will explain the sketch which I will now attempt to
put in the dropbox.
Stealth Pilot





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Stealth Pilot
 
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Default Airgun plans?

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

arrgh
someone has purged my favourites.
what is the url of the drop box?
Stealth pilot
  #15   Report Post  
Posted to rec.crafts.metalworking
Stealth Pilot
 
Posts: n/a
Default Airgun plans?

look for air rifle in the drop box.


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Dave Lyon
 
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Default Airgun plans?

What specifically are you trying to accomplish?

I've built a CO2 powered gun for use against paintball tanks. It fires a
foam projectile that I also build at 250 fps. It could easily be designed to
shoot much harder.

I ran into 2 tricky areas. The first one was making a projectile that
wouldn't hurt somebody. The 2nd was getting O-rings that could handle the
800 + psi of CO2.

Let me know if you'd like to see some pictures of my gun. If you want, I can
help you design one to meet your criteria.
"Gunner" wrote in message
...
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



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Posted to rec.crafts.metalworking
J. Clarke
 
Posts: n/a
Default Airgun plans?

Gunner wrote:

On Mon, 24 Apr 2006 01:47:41 -0500, Don Foreman
wrote:

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:

On 23 Apr 2006 09:08:19 -0700, wrote:

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?

Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.


I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....



You figure the circuitry out..Ill build the Steamgun. Stainless steel
of course. The water injection/volume control sounds a bit interesting
to figure out..but if a steam engine can do it...


With limited amounts of oxygen present I wonder how much erosion there would
be on the electrodes? Incidentally the velocity of sound in steam at 212F
is about 1300 ft/sec, about 20% higher than the velocity of sound in air at
standard temperature and pressure. Be interesting if you could hit .45ACP
ballistics with an arc-steam gun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist


--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
  #18   Report Post  
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Dave Lyon
 
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Default Airgun plans?




If a guy had a free source of high-pressure helium, that might be
even better because sonic velocity (hence max attainable muzzle
velocity) is considerably higher in helium than in CO2.


It's also considerably more difficult to contain. You'll have a tough time
building seals for that.

OTOH, compressed air is a little faster than CO2, able to generate higher
pressures, and easy to get your hands on.


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Posted to rec.crafts.metalworking
Terry Mayhugh
 
Posts: n/a
Default Here is what you are looking for...

http://www.burntlatke.com/bb.html

Machine the Vortex block from aluminum.

"Gunner" wrote in message
...
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



  #20   Report Post  
Posted to rec.crafts.metalworking
Rex B
 
Posts: n/a
Default Airgun plans?


Don Foreman wrote:
You figure the circuitry out..Ill build the Steamgun. Stainless steel
of course. The water injection/volume control sounds a bit interesting
to figure out..but if a steam engine can do it...


The circuitry is no problem, but I have no idea at the moment how to
initiate a rapid ( 1000 microseconds) capacitive discharge into a
drop of water, other than perhaps a consumable electrode. Figuring
that out (or not) would take some experimentation in hope of
inspiration. Might be an interesting winter project, though.


Add some salt or other mineral content to the water so it would take a
charge?


  #21   Report Post  
Posted to rec.crafts.metalworking
knowone
 
Posts: n/a
Default Airgun plans?

Here is a great link for an electrothermal rifle:
http://www.powerlabs.org/electrothermal.htm



"Gunner" wrote in message
...
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



  #22   Report Post  
Posted to rec.crafts.metalworking
Ted Edwards
 
Posts: n/a
Default Airgun plans?

Don Foreman wrote:
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!
...
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry.


Even cheaper to use NiMH and they are better for short bursts of high
current. BTW, how did you get 29,000?

Four NiMH 2500mAh cells:

4*1.2volts*(2.5*3600Amp-seconds) = 44928 Joules

Yes?

Ted
  #23   Report Post  
Posted to rec.crafts.metalworking
J. Clarke
 
Posts: n/a
Default Airgun plans?

Don Foreman wrote:

On Mon, 24 Apr 2006 10:32:16 GMT, Gunner
wrote:

On Mon, 24 Apr 2006 01:47:41 -0500, Don Foreman
wrote:

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:

On 23 Apr 2006 09:08:19 -0700, wrote:

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?

Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.

I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....



You figure the circuitry out..Ill build the Steamgun. Stainless steel
of course. The water injection/volume control sounds a bit interesting
to figure out..but if a steam engine can do it...


The circuitry is no problem, but I have no idea at the moment how to
initiate a rapid ( 1000 microseconds) capacitive discharge into a
drop of water, other than perhaps a consumable electrode. Figuring
that out (or not) would take some experimentation in hope of
inspiration. Might be an interesting winter project, though.


It occurs to me that the chamber could be a problem too--can't use metal or
you'll arc from the electrode to the chamber wall instead of between
electrodes. That's likely to limit the possible chamber pressure.

It also occurs to me that if you pull this off at all you could run a series
of electrodes timed to fire as the projectile passes--that could give you
some _very_ hot gases in the chamber and might allow a quite remarkable
muzzle velocity, _if_ you can contain them.

Hmm, thinking further, why water? Vaporize a solid and you should get even
more pressure. Instead of electrodes and water maybe a piece of carbon
that gets vaporized? That way you use current and not voltage, and arcing
over to the chamber walls becomes less of an issue, although you'll still
need an insulator that will handle the pressure. Probably have to clean
the barrel every few shots.

Meanwhile, CO2 is probably more practical.

If a guy had a free source of high-pressure helium, that might be
even better because sonic velocity (hence max attainable muzzle
velocity) is considerably higher in helium than in CO2.


--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
  #24   Report Post  
Posted to rec.crafts.metalworking
Gunner
 
Posts: n/a
Default Airgun plans?

On Mon, 24 Apr 2006 10:55:23 -0500, Don Foreman
wrote:

On Mon, 24 Apr 2006 10:32:16 GMT, Gunner
wrote:

On Mon, 24 Apr 2006 01:47:41 -0500, Don Foreman
wrote:

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:

On 23 Apr 2006 09:08:19 -0700, wrote:

Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?

Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.

I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....



You figure the circuitry out..Ill build the Steamgun. Stainless steel
of course. The water injection/volume control sounds a bit interesting
to figure out..but if a steam engine can do it...


The circuitry is no problem, but I have no idea at the moment how to
initiate a rapid ( 1000 microseconds) capacitive discharge into a
drop of water, other than perhaps a consumable electrode. Figuring
that out (or not) would take some experimentation in hope of
inspiration. Might be an interesting winter project, though.

Meanwhile, CO2 is probably more practical.

If a guy had a free source of high-pressure helium, that might be
even better because sonic velocity (hence max attainable muzzle
velocity) is considerably higher in helium than in CO2.



What if one used Hydrogen peroxide..consumer grade, rather than plain
tap water?

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
  #25   Report Post  
Posted to rec.crafts.metalworking
Gunner
 
Posts: n/a
Default Airgun plans?

On Mon, 24 Apr 2006 14:23:17 GMT, "Dave Lyon"
wrote:

What specifically are you trying to accomplish?

I've built a CO2 powered gun for use against paintball tanks. It fires a
foam projectile that I also build at 250 fps. It could easily be designed to
shoot much harder.

I ran into 2 tricky areas. The first one was making a projectile that
wouldn't hurt somebody. The 2nd was getting O-rings that could handle the
800 + psi of CO2.

Let me know if you'd like to see some pictures of my gun. If you want, I can
help you design one to meet your criteria.


Cool. We can remove the criteria that it be unable to harm anyone. A
gun of any sort will be dangerous if mishandled and frankly..more
power is better in conjuction with a large heavy projectile.

Gunner

"Gunner" wrote in message
.. .
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist


  #26   Report Post  
Posted to rec.crafts.metalworking
Gunner
 
Posts: n/a
Default Here is what you are looking for...

On Mon, 24 Apr 2006 16:35:22 GMT, "Terry Mayhugh"
wrote:

http://www.burntlatke.com/bb.html

Machine the Vortex block from aluminum.


Interesting. Though I think making it from aluminum would not be a
good idea, as those steel bbs would peen it out of shape pretty
quickly. Steel with some case hardening would be better I think.

Interesting concept though.

Thanks!

Gunner


"Gunner" wrote in message
.. .
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist
  #27   Report Post  
Posted to rec.crafts.metalworking
Don Foreman
 
Posts: n/a
Default Airgun plans?

On Mon, 24 Apr 2006 17:43:42 GMT, Ted Edwards
wrote:

Don Foreman wrote:
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!
...
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry.


Even cheaper to use NiMH and they are better for short bursts of high
current. BTW, how did you get 29,000?

Four NiMH 2500mAh cells:

4*1.2volts*(2.5*3600Amp-seconds) = 44928 Joules

Yes?

Ted


I used alkies because they're cheap and readily available, and I
derated them because they don't deliver full rated amp-hours at higher
discharge rates. 30 joules in 3 seconds is 10 watts or a bit over 2
amps at 4.8 volts. NiMH AA cells could probably do that, might need
to go to D cells in alkaline.

Lithiums would work and would be very lightweight, but they're pricey.
  #28   Report Post  
Posted to rec.crafts.metalworking
Don Foreman
 
Posts: n/a
Default Airgun plans?

On Mon, 24 Apr 2006 14:23:17 GMT, "Dave Lyon"
wrote:

What specifically are you trying to accomplish?

I've built a CO2 powered gun for use against paintball tanks. It fires a
foam projectile that I also build at 250 fps. It could easily be designed to
shoot much harder.

I ran into 2 tricky areas. The first one was making a projectile that
wouldn't hurt somebody. The 2nd was getting O-rings that could handle the
800 + psi of CO2.

Let me know if you'd like to see some pictures of my gun. If you want, I can
help you design one to meet your criteria.
"Gunner" wrote in message
.. .


I'd like to see that too. I'm specifically interested in the valving
mechanism you used. I have a need to shoot maybe a dozen golfballs
to break up some squirrel nests, and I have a 20-lb bottle of CO2.
250 fps would be more than I need. 100 ft/sec would get me about
150 ft of height, which should be ample since the squirrel nests are
about 40 feet up. That'd keep things at a pretty safe 20 joules.

A slingshot doesn't quite cut it. I need a large enough projectile
to break up those nests, not just punch holes in them.
  #29   Report Post  
Posted to rec.crafts.metalworking
David R. Birch
 
Posts: n/a
Default Airgun plans?

Don Foreman wrote:

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:


Anyone got a source for plans for making your own air rifle? Id
like to machine one. Just about any type. Think it would be a fun
project.

Something run or charged from CO2 welding tank might be fun.


I'm contemplating a *low energy* golfball cannon suitable for
decimating squirrel nests in a residential neighborhood. No plans
yet. There's a clear field of fire for a good 300 feet to the
south, with a 20' freeway sound wall behind it. I'm thinking max
altitude of maybe 200 feet, which is about 10 joules of muzzle
energy with a golfball.


Best not try this in Wisconsin in the presence of a game warden,
molesting squirrel nests, urban or rural, is verboten.

David
  #30   Report Post  
Posted to rec.crafts.metalworking
Don Foreman
 
Posts: n/a
Default Airgun plans?

On Tue, 25 Apr 2006 02:21:45 GMT, "David R. Birch"
wrote:

Don Foreman wrote:

On Sun, 23 Apr 2006 07:39:50 GMT, Gunner
wrote:


Anyone got a source for plans for making your own air rifle? Id
like to machine one. Just about any type. Think it would be a fun
project.

Something run or charged from CO2 welding tank might be fun.


I'm contemplating a *low energy* golfball cannon suitable for
decimating squirrel nests in a residential neighborhood. No plans
yet. There's a clear field of fire for a good 300 feet to the
south, with a 20' freeway sound wall behind it. I'm thinking max
altitude of maybe 200 feet, which is about 10 joules of muzzle
energy with a golfball.


Best not try this in Wisconsin in the presence of a game warden,
molesting squirrel nests, urban or rural, is verboten.

David


The Wisconsin squirrels (and feral cats) are safe from me.


  #31   Report Post  
Posted to rec.crafts.metalworking
DoN. Nichols
 
Posts: n/a
Default Airgun plans?

According to Stealth Pilot :

[ ... ]

arrgh
someone has purged my favourites.
what is the url of the drop box?


http://www.metalworking.com

Enjoy,
DoN.

--
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 ---
  #32   Report Post  
Posted to rec.crafts.metalworking
Dave Lyon
 
Posts: n/a
Default Airgun plans?


"Don Foreman" wrote in message
...
On Mon, 24 Apr 2006 14:23:17 GMT, "Dave Lyon"
wrote:

What specifically are you trying to accomplish?

I've built a CO2 powered gun for use against paintball tanks. It fires a
foam projectile that I also build at 250 fps. It could easily be designed

to
shoot much harder.

I ran into 2 tricky areas. The first one was making a projectile that
wouldn't hurt somebody. The 2nd was getting O-rings that could handle the
800 + psi of CO2.

Let me know if you'd like to see some pictures of my gun. If you want, I

can
help you design one to meet your criteria.
"Gunner" wrote in message
.. .


I'd like to see that too. I'm specifically interested in the valving
mechanism you used. I have a need to shoot maybe a dozen golfballs
to break up some squirrel nests, and I have a 20-lb bottle of CO2.
250 fps would be more than I need. 100 ft/sec would get me about
150 ft of height, which should be ample since the squirrel nests are
about 40 feet up. That'd keep things at a pretty safe 20 joules.

A slingshot doesn't quite cut it. I need a large enough projectile
to break up those nests, not just punch holes in them.


I didn't know how to use (or where it is) the board that you guys have for
pictures, so I sent some to Don. Hopefully he'll be kind enough to post
them.
I included a crude iges file that I used to machine it from. Please don't
assume this is a safe design. I am not an engineer, and we're dealing with
some very high pressures.

The gun shown operates from CO2. At room temperature, it is somewhere
around 800 psi. The black hose connects to a standard CO2 tank used for
paintball. They hold about 20 ozs, and can be worn on your back

In the iges file, you can see on the left side of the plan view a large
drilled hole (I think it was around .687) This is used as a reservoir to
hold the CO2 ready for the next shot. With a bit of studying, you should be
able to see the valve. It is held up to seal against the top by a spring.
The valve has a very small air passage that allows the CO2 to bleed by it so
the pressure is the same on both sides of the valve. There is a seal on the
bottom side of the valve that is held in place by some bellville springs, a
ball bearing, and the shape of the trigger. When the trigger is pulled, the
air underneath the valve is allowed to escape very quickly. The spring can
no longer hold the pressure that is above the valve, so it moves down
allowing the gas to escape from the passageway leading to the barrel.


  #33   Report Post  
Posted to rec.crafts.metalworking
Ecnerwal
 
Posts: n/a
Default Airgun plans?

In article ,
Don Foreman wrote:

I'd like to see that too. I'm specifically interested in the valving
mechanism you used. I have a need to shoot maybe a dozen golfballs
to break up some squirrel nests, and I have a 20-lb bottle of CO2.
250 fps would be more than I need. 100 ft/sec would get me about
150 ft of height, which should be ample since the squirrel nests are
about 40 feet up. That'd keep things at a pretty safe 20 joules.

A slingshot doesn't quite cut it. I need a large enough projectile
to break up those nests, not just punch holes in them.


Golfball crossbow? Might be simpler and quicker to build than air, with
(perhaps) similar accuracy potential?

--
Cats, coffee, chocolate...vices to live by
  #34   Report Post  
Posted to rec.crafts.metalworking
Don Foreman
 
Posts: n/a
Default Airgun plans?

On Tue, 25 Apr 2006 14:02:11 GMT, "Dave Lyon"
wrote:


"Don Foreman" wrote in message
.. .
On Mon, 24 Apr 2006 14:23:17 GMT, "Dave Lyon"
wrote:

What specifically are you trying to accomplish?

I've built a CO2 powered gun for use against paintball tanks. It fires a
foam projectile that I also build at 250 fps. It could easily be designed

to
shoot much harder.

I ran into 2 tricky areas. The first one was making a projectile that
wouldn't hurt somebody. The 2nd was getting O-rings that could handle the
800 + psi of CO2.

Let me know if you'd like to see some pictures of my gun. If you want, I

can
help you design one to meet your criteria.
"Gunner" wrote in message
.. .


I'd like to see that too. I'm specifically interested in the valving
mechanism you used. I have a need to shoot maybe a dozen golfballs
to break up some squirrel nests, and I have a 20-lb bottle of CO2.
250 fps would be more than I need. 100 ft/sec would get me about
150 ft of height, which should be ample since the squirrel nests are
about 40 feet up. That'd keep things at a pretty safe 20 joules.

A slingshot doesn't quite cut it. I need a large enough projectile
to break up those nests, not just punch holes in them.


I didn't know how to use (or where it is) the board that you guys have for
pictures, so I sent some to Don. Hopefully he'll be kind enough to post
them.
I included a crude iges file that I used to machine it from. Please don't
assume this is a safe design. I am not an engineer, and we're dealing with
some very high pressures.

The gun shown operates from CO2. At room temperature, it is somewhere
around 800 psi. The black hose connects to a standard CO2 tank used for
paintball. They hold about 20 ozs, and can be worn on your back

In the iges file, you can see on the left side of the plan view a large
drilled hole (I think it was around .687) This is used as a reservoir to
hold the CO2 ready for the next shot. With a bit of studying, you should be
able to see the valve. It is held up to seal against the top by a spring.
The valve has a very small air passage that allows the CO2 to bleed by it so
the pressure is the same on both sides of the valve. There is a seal on the
bottom side of the valve that is held in place by some bellville springs, a
ball bearing, and the shape of the trigger. When the trigger is pulled, the
air underneath the valve is allowed to escape very quickly. The spring can
no longer hold the pressure that is above the valve, so it moves down
allowing the gas to escape from the passageway leading to the barrel.


I can post your photos to the dropbox, but they want a .txt file
(words) along with them to describe what the photos are of or about.

What program opens an .IGS file? All I have for CAD SW is AutoCAD
R-14. If you can convert that to DXF (version 14), I can convert
that to Adobe .pdf .

  #35   Report Post  
Posted to rec.crafts.metalworking
Jeff Wisnia
 
Posts: n/a
Default Airgun plans?

Don Foreman wrote:

On Sun, 23 Apr 2006 21:33:24 GMT, Gunner
wrote:


On 23 Apr 2006 09:08:19 -0700, wrote:


Gunner,

Why not try something exotic such as an electrically fired gun?

The propellant is a couple of drops of plain, old, water, through wich
a heavy electric current is discharged from a capacitor.

What do you think?


Sounds interesting..and complicated. Im not much of an electronics
tech to be frank. Board changer is more my skill level. Getting down
to component level and I start to flounder. And I suspect that the
power supply and caps bank needed to do instant electrolysis might be
a bit heavy.



I suspect that this isn't electrolysis but simply instant
high-pressure hot steam produced by heat from a spark/arc.

It's an interesting idea.

A fairly powerful production air rifle has energy of about 30 joules
(22 ft lb), as a .177 with 1100 fps muzzle velocity. This would not
require a large capacitor. One available 48 joule 450-volt
photoflash cap is 1-3/4" dia x 2-1/2" long. It could be charged in
a few seconds with 4 AA cells and suitable circuitry. Four alkaline
AA cells contain a total of about 29,000 joules, i.e. many shots!

However, for perspective, a .22 rimfire short is about 157 joules.
I don't know what energy the Lewis & Clark or Austrian infantry
rifles had. However, musing on....

The original .45 ACP round in a long barrel (SMG) is about 520
joules.
http://www.sightm1911.com/Care/45acp.htm . Taking it
to that level, there is a 2000 volt 500uF 1000 joule capacitor that
is 2" dia x 4-1/8" long, and you'd get at least 25 shots out of 4 AA
cells (for 2 bux) even with fairly lousy efficiency in the
circuitry. That's twice the energy of the .45 ACP but still only
half the energy of a .30-30 or 7.62mm Kurz (short). Still, not bad
for an "air" rifle with no flash and no supersonic "crack". Subsonic
bang is more difficult to auditorily localize because it contains
less high frequency content. Phase resolution is therefore less with
the fixed distance beween ears.

What about pressure build time and attainable muzzle velocity? I
can attest that a 50 joule photoflash cap will vaporize the end of a
screwdriver with a report that sounds a lot more like the crack of a
rifle than the bang of a pistol, which infers that it can dump its
load rather quickly producing a hypersonic shockwave.

Vaporizing water with a shot of energy would produce much more volume
of expanding high-pressure gas to accelerate a projectile continuously
thru the length of a barrel. However, an "air" rifle can not
attain sonic velocity unless the "air" is quite hot, so higher
energy infers large-caliber low-velocity bullets, most effective at
ranges under 100 meters and probably best at less than 50 meters.

It's an interesting idea. There'd be a few details to work out.....



Just for the halibut I searched for "steam gun" with Google. Gess wot?

http://tinyurl.com/kaosx

and also this one from the US Civil War

http://tinyurl.com/h68kv

But I'm not sure that one used steam to squirt the projectile out of a
barrel, there's mention of "centrifugal force". Maybe it was really just
a steam powered projectile "flinger".

Jeff

--
Jeffry Wisnia

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  #36   Report Post  
Posted to rec.crafts.metalworking
Frank Warner
 
Posts: n/a
Default Airgun plans?

In article , Gunner
wrote:

Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.


Gunner, there's some interesting info here on the Lewis & Clark air
rifle, including extensive diagrams of the mechanisms in various states
of safe, cocked, firing, etc. Seems to me a reasonably talented
machinist can build something similar w/o too much difficulty.

http://www.beemans.net/lewis%20assault%20rifle.htm

-Frank

--
Here's some of my work:
http://www.franksknives.com/
  #37   Report Post  
Posted to rec.crafts.metalworking
Dave Lyon
 
Posts: n/a
Default Airgun plans?


Gunner, there's some interesting info here on the Lewis & Clark air
rifle, including extensive diagrams of the mechanisms in various states
of safe, cocked, firing, etc. Seems to me a reasonably talented
machinist can build something similar w/o too much difficulty.

http://www.beemans.net/lewis%20assault%20rifle.htm

-Frank



Wow! that is a great page of info!
You can bet I'll be studying that for my next gun.


  #38   Report Post  
Posted to rec.crafts.metalworking
R. O'Brian
 
Posts: n/a
Default Airgun plans?

I haven't followed this thread too closely, but you might look at "THE
MODERN PNEUMATIC AIRGUN - A PRACTICAL STEP BY STEP GUIDE TO BUILDING YOUR
OWN" by H. M. Buckley I think it is a precharged pneumatic.

Randy



"Gunner" wrote in message
...
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist



  #39   Report Post  
Posted to rec.crafts.metalworking
R. O'Brian
 
Posts: n/a
Default Airgun plans?

You can get the book at http://www.gunbooks.co.uk/air-guns.cfm


"R. O'Brian" wrote in message
news:ji65g.4329$B42.2144@dukeread05...
I haven't followed this thread too closely, but you might look at "THE
MODERN PNEUMATIC AIRGUN - A PRACTICAL STEP BY STEP GUIDE TO BUILDING YOUR
OWN" by H. M. Buckley I think it is a precharged pneumatic.

Randy



"Gunner" wrote in message
...
Anyone got a source for plans for making your own air rifle? Id like
to machine one. Just about any type. Think it would be a fun project.

Something run or charged from CO2 welding tank might be fun.

Gunner

"I think this is because of your belief in biological Marxism.
As a genetic communist you feel that noticing behavioural
patterns relating to race would cause a conflict with your belief
in biological Marxism." Big Pete, famous Usenet Racist





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