Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 69 users online :: 4 registered, 0 hidden and 65 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

Lathe turned pellets

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

Unread postAuthor: jeepkahn » Sat Jun 06, 2009 3:24 pm

USGF wrote:John,

If you can machine a steel mold, then you might use it as a cold forming die rather than a hot pour mold. Place a lead slug that is slightly larger than the finished projectile in the dies. USGF


Not trying to hijack, but this is a brilliant idea, with a multiton press to do the pressing, one could make a mold similar to gippetos(but made from steel) use a punch mandrel slightly smaller than the slug, and extrusion press fosters slugs with extremely thin sidewalls....
  • 0


jeepkahn
Colonel
Colonel
 
Posts: 747
Joined: Fri Jan 09, 2009 1:11 pm
Location: Triad, NC, USA
Reputation: 0

Unread postAuthor: john bunsenburner » Sat Jun 06, 2009 4:26 pm

I'v been exagurating with the 500-700meters, realistically it will be 300-500 meters if im eager, 100 or so normally. I will however see how far away i can place a traget to get accurate results. the cold pres forming sounds fairly complecated as i don't have either milling facilities nor a hydraulic press. I think(correct me if im wrong) in my cas eit may be better to just make an aluminium mold and to pour the lead. The process would be more intresting if i had the right tools, i don't however and so im afraid it wouldn't be worth while tryign for me.
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: USGF » Sat Jun 06, 2009 6:42 pm

john bunsenburner wrote:SNIP the cold pres forming sounds fairly complecated as i don't have either milling facilities nor a hydraulic press. SNIP


John, the accuracy of your shot in part depends on the precision of your rounds. If your round is not uniform, you will get less that stellar results. One reason I and Jeep mention coldforming is to keep long term cost down. Heating lead and pouring will get time consuming if not energy intensive. What I like most in doing this in the past is getting the lead to have no porosity or air veins due to a cold pour. I know a steel mold/die is hard to make but a hydraulic car jack should be within your reach. For a small 6 to 8 mm setup, I could not see needing more than 5 tons.

FYI, I have cold formed copper, lead and aluminum parts in the past so I know it can be done. It will take more than a hacksaw and drill press.
USGF
  • 0

User avatar
USGF
Master Sergeant
Master Sergeant
 
Posts: 173
Joined: Sun Mar 08, 2009 5:39 am
Reputation: 0

Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 2:20 am

Well look to make my mold I would do the following, i assume this can be adapted to steel but i see a few problems these i'll mention at the end:

Firstly a piece of steel round bar with the right diameter(slightly over sized, i can always make it smaller) will be inserted into my 3jaw chuck.

Next the chuck is turned at an appropriate speed and using an HSS tool bit and a file i will turn the pellet. First the tip then the body, the pellet is not removed from the steel stock so that atleast 4-5cm are sticking out at the bottom.

Now a piece of aluminium stock that has been cut in half will be placed into the chuck and turned. A hole that has the diameter of the deepest part of the pellet will be driled in it's middle.

Then the previously made steel pellet drill bit will be mounted in my jacob's chuck and inserted into the hole, the 3jaw chuck will be loosened to acomodate for this.

The chuck is tightened as much as it can be and the lathe turned on, it is left to turn until no more material is cut of.

Now the chuck is tightened again and the above procedure is repeated until the whole pellet desighn is engraved within the aluminium.

Now the main problem would be attapting this to steel. Special tools would be needed to lathe HSS, carbide or anything else hard eanough to "drill" a pellet into steel.
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: USGF » Sun Jun 07, 2009 3:59 am

John,

Ok, uh, Here's how I would do it. I would turn the pellet just as you describe. However, I would use a heat treatable steel like O-1 or A-2. They are easy to heat treat with instructions found anywhere on the net. Next, I would either mill, grind or hack off exactly half the diameter of the pellet away so you have a D shaped pellet looking at it from the end. Try to file some relief into the pellet for the remaining 170° or so. This keeps the body from dragging in the cut. Heat treat and draw to a light straw color. You will understand this when you look up heat treating instructions.

Next, stone or lightly grind your flat face to get a good cutting edge. You have made a D bit style endmill. This is NOT going to be a really clean cutting cutter. It takes years of experience to get good at it. It will work if you have patience. Set up your steel or aluminum half block in place of your tool post. Shift the lathe into a slow speed and proceed to cut into the block. You must use lots of cutting fluid. Keep chips out and help reduce heat buildup. Be careful, you need to file your relief so it creates a standard right hand cut. Otherwise, the bit will attempt to lift the carraige off the lathe. If you can get a milling attachment such as this,

http://littlemachineshop.com/products/p ... uctID=1681

life will be a little easier. You need to align the left and right sides, most likely with another pellet placed in and held together for line drilling.

I may have left small details out. I will try to answer any questions you may have. Have fun. :?

USGF
  • 0

User avatar
USGF
Master Sergeant
Master Sergeant
 
Posts: 173
Joined: Sun Mar 08, 2009 5:39 am
Reputation: 0

Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 4:18 am

How about i take a standered drill bit and turn it on my lathe. I hold a grinding stone ot it so make a pellet like shape, then use the procedure I explained?
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: USGF » Sun Jun 07, 2009 5:29 am

john bunsenburner wrote:How about i take a standered drill bit and turn it on my lathe. I hold a grinding stone ot it so make a pellet like shape, then use the procedure I explained?


Sounds do-able in theory, in practice, unless you have access to a cutter grinder, you will not cut HSS or carbide into the form you need. You will still need to have clearance ground in etc. A lot of work

USGF
  • 0

User avatar
USGF
Master Sergeant
Master Sergeant
 
Posts: 173
Joined: Sun Mar 08, 2009 5:39 am
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 5:35 am

One question, can i use aluminium for the die or does it have to be steel?
I will need a grinder for my HSS blanks to make tools so really i guess it might be do able.
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Jun 07, 2009 5:39 am

dewey-1 wrote:JSR where are you?
Give john a better explanation if possible than I can!


To the rescue! :D

Aside from the usual demands on a consistent pressure fill, valve, trigger etc for accuracy, consider the following:

There is no doubt that a subsonic projectile can reach out to 1000m if fired at the right angle, but it needs to be built to high specifications in terms of ballistic coefficient in order to retain as much speed as possible during flight. The flechettes Jeep posted, while made for dropping out of aircraft powered by gravity rather than being fired, are a good illustration of the ideal sort of parameters you should be looking at - dense material and long, narrow shape.

Even with the best projectile, you're going to firing at a high angle so it's important to start increasing range gradually in order to be aware of projectile drop over distance. Also, as your projectile's going relatively slowly, you're going to have to be very aware of wind, at long ranges it will take the projectile a while to reach its target and it has plenty of time to be deflected.

Still, relatively long range accuracy with subsonic projectiles is not unknown, the 510 whisper is a good example of what can be done.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 6:47 am

Well besides ammo and it's shape and a strait barrel ect. what else do i have to keep in mind?
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Jun 07, 2009 6:56 am

There are some parameters mentionedhere.

I think the most important thing is consistency. The projectile must leave the barrel at the same velocity and in the same direction every time.

Also note that barrel straightness is not as revevant as muzzle precision, to give you an extreme example from the Beeman collection:

Image

After one of the big SHOT trade shows, the owners of the Westinger & Altenburger Co. (Feinwerkbau) of Germany presented us with this amazing feat of airgunsmithing - a Beeman/Feinwerkbau Model 2 CO2 pistol with the barrel making a complete twist around the gas cylinder! The gun actually shoots quite well! Note that the all-important final inch(25 mm) or so is straight - that and the crown are the only really important parts of the barrel as far as accuracy is concerned. When some shooter would say " I think I see some little defect in the rifling way down inside my barrel, or the middle is a little off, or the barrel is not quite straight, and that is why I am not shooting well" , the airgunsmiths loved to bring out this gun and ask if his gun was more off line than this one!
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 7:02 am

Is there a difference between painballs and pellets when it comes to accuracy considerations?
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Jun 07, 2009 7:07 am

Other than the "gentle" acceleration specified in order to avoid distorting or damaging the paintball in the barrel, all the other points apply to all projectiles where accuracy is concerned.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: john bunsenburner » Sun Jun 07, 2009 7:22 am

Ok so long barrel, consitency and a port for the air at the end which can also be an intergrated silencer? Why didn't you just type that out...Oh well thanks for the help jsr. back to my earlier question: can my die be aluminium.

Oh before i forget: you said that thread covered SOME things that ar eimportant for accuracy, what are soem others?
  • 0

"Did you ever stop to think that out of the seven deadly sins envy is the only one which doesn't give the sinner even momentary pleasure"-George Will
User avatar
john bunsenburner
Major General
Major General
 
Posts: 1446
Joined: Sun Oct 19, 2008 5:13 am
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Jun 07, 2009 7:52 am

john bunsenburner wrote:You said that thread covered SOME things that ar important for accuracy, what are some others?


"obvious" things like trigger - it can't be too difficult to operate, otherwise it will throw your aim off if you have to squeeze the trigger too hard. You also need a good telescopic sight on a rigid mount, preferably with a mil-dot reticle.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

PreviousNext

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'