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Registered Member #215
Joined: Sun Feb 19 2006, 09:14PM
Location:
Posts: 30
Got it all hooked up last week and she was good to go!
Cap is 250v 7500 uF. SCR is triggered by 9v battery like suggested [Works perfectly BTW ] Projectiles are custom machined pieces of 1/4" steel rod. The tips were put on with a drill press [stick the rod in the chuck and used sandpaper, grinding stones and files to shape it]. The projectile shown in the pic beside the coil is 2" long. This coming week I'm going to experiment with different attributes to the projectiles [Ex: Having slots run down the middle, having rings cut into the sides, cutting rifling grooves into the front half etc] to see what works best. Right now I can shoot through 3 pop cans and have the projectile still get stuck into a high speed archery target [that foam is TOUGH!]
This was brought into school and used in a demonstration of electromagnets. Needless to say, it was quite the popular item
Everything seems to work quite well on this gun. Coil was a pain to wind, though. It's MOT primary wire. This was given to me by a friend, all nice and spooled up. Each layer is cemented in place to keep everything steady. I had to actually bolt the coil down due to excessive recoil [first time I've experianced this with a CG] and to keep all avalible energy delivered to projectile.
Registered Member #179
Joined: Thu Feb 16 2006, 02:08AM
Location: Hagerstown, Maryland - Close to Prime Outlets
Posts: 287
Nice job! Did you happen to solder those ring terminals onto the wires? I found on mine that if they weren't soldered they'd slowly burn away the wire strands inside the ring and eventually blow completely off.
Registered Member #158
Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282
Looks like a great first gun (this is your first, right?). Just a couple of questions, did you tune this setup? Like starting position, number of turns in the coil, etc.? And how high did you charge the cap? Keep up the good work.
Registered Member #215
Joined: Sun Feb 19 2006, 09:14PM
Location:
Posts: 30
Ring terminals were crimped then soldered. Some are just soldered and uncrimped...meh
Tuned? Well...more or less [haha] I wound the coil to the perameters of the cap and it worked out pretty nice.
First coilgun? Not by a longshot! But this is exponentially more powerful then the others [which were all photoflash+ pushbutton etc]
Made a pretty cool discovery this week while working in the shop at school. Some guy had broken a drill bit, so I picked it up and looked at it. Coilgun bullet ideas were floating through my head at the time, and it turned out I was thinking of ways to rifle a projectile. Well, you can see whats coming! Drill bits! You can cut and sharpen any way you like. The flutes will catch the air as it is accellerated and pick up centrifugal spin. Has anyone tried this? Going to fabricate some this weekend. Needless to say I've got quite a few broken 'bits needing some kind of usage
Registered Member #342
Joined: Thu Mar 23 2006, 08:27PM
Location: TX, USA
Posts: 20
Tipp wrote ...
Cap is 250v 7500 uF. SCR is triggered by 9v battery like suggested [Works perfectly BTW ] Projectiles are custom machined pieces of 1/4" steel rod. The tips were put on with a drill press [stick the rod in the chuck and used sandpaper, grinding stones and files to shape it]. The projectile shown in the pic beside the coil is 2" long. This coming week I'm going to experiment with different attributes to the projectiles [Ex: Having slots run down the middle, having rings cut into the sides, cutting rifling grooves into the front half etc] to see what works best. Right now I can shoot through 3 pop cans and have the projectile still get stuck into a high speed archery target [that foam is TOUGH!]
Did you machine the steel yourself, or did you get it ordered from somewhere? Ive looked in Home depot and Lowes, and no-one carries steel bars, do you have an idea of where I can buy a couple of bars from?
Banned Registered Member #110
Joined: Fri Feb 10 2006, 12:23AM
Location: Banned City
Posts: 85
Did you ask or looked? Because of you asked and they said no, then those are some weird Home Depots and Lowes you went to. The rods are next to the sheet metal section. They got tons of rods: round, square, hollowed walls, U-shapes, L-shapes, steel, aluminum, and all from 1/8 to 2 inches. Well thats what the stores in Southern California sport anyway. RC, airplane hobby shops carry a goo supply themselvse, there is called music wire.
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Finished Coilgun
] Projectiles are custom machined pieces of 1/4" steel rod. The tips were put on with a drill press [stick the rod in the chuck and used sandpaper, grinding stones and files to shape it]. The projectile shown in the pic beside the coil is 2" long. This coming week I'm going to experiment with different attributes to the projectiles [Ex: Having slots run down the middle, having rings cut into the sides, cutting rifling grooves into the front half etc] to see what works best. Right now I can shoot through 3 pop cans and have the projectile still get stuck into a high speed archery target [that foam is TOUGH!]
