PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 3, 2005 13:29:26 GMT -5
yea, 3/4 delrin is pretty cheap, about $2 a foot. but the vendors I've looked at don't really post shipping info or costs. I actually sent away for a catalog from a major plastics manufacturer/seller, and was looking through it the other day.
yea, definately a delrin bolt, no reason not to. stong, low density, self lubricating. good qualities for this application
gonna try and to some research to see if nylon is actually any better. slightly more expensive, but you can get it molybdenum disuplhide filled for even lower friction, and still be significantly cheaper than PTFE bar, or even PTFE filled delrin I think
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 3, 2005 13:50:33 GMT -5
whoooo! just now had a brainstorm for one of the big holdups on the loader design. how to keep some amout of pressure on all the balls in the stack so there's always positive feed without just having a motor run all the time and crush them. I was looking at the other items the guy I bought the ram valves off was selling, and i found this: cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26227&item=7512708268&rd=1&ssPageName=WDVWa magnetic clutch. doesn't work like a standard cluctch to completely disengage the drive, it uses permanent magnets that are spun by the drive to retard movement. I could probably design a magnetic drive couple that only has so much sticking power, and as soon as too much torque is input, it slips. genius, eh? all I need is some sort of spring in the drive line to hold a bit of force on the balls when the drive motor switches off. Well, the switch too, but, meh, it's not as vitally important with the magnetic clutch idea. with the slip clutch, I can just say if gun has fired within x seconds, leave motor on, and the clutch will keep the balls from being turned to paintball soup
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 3, 2005 17:08:18 GMT -5
found the shipping information at usplastic.com ordered 2 ft of 3/4" delrin for $10
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Tharnex
yah....i spend a lot of time here
Sargeant
Posts: 122
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Post by Tharnex on May 3, 2005 21:58:32 GMT -5
woohoo, just a reminder 25 more days to go...... i think the stuff is called nylatron or something like that, somewhat the the same properities but smaller differences i dunno, they'll make a bolt out of cheese if it willl stop ball breaks,is lighter in weight and increase air flow;)
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 3, 2005 22:28:14 GMT -5
the force acting on the bolt is more important than the material of the bolt as far as ball breaks are concerned
and airflow is a function of cross-sectional surface area of the internal bore, and surface finish. (I think. does that sound right??)
that, and nylatron woulda been nice to know about before I ordered the derlin! :-P actually, the delrin will work just fine, I just need to get access to someone who can turn it down for me
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 5, 2005 13:14:01 GMT -5
got the delrin delivered today at 1:45. I'd say that's fairly impressive (so, who has a lathe?? :-D )
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 8, 2005 10:56:08 GMT -5
messed around with the microcontroller a bit last night, and a bit more this morning, and I got the analog to digital converter working, in conjunction with interrupts, so, I think I have figured out about everything I'm gonna need for the final code
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on May 15, 2005 21:36:01 GMT -5
had a sudden revelation to make potentially make the cycle rate even higher through further reductions in reciprocating mass.
bolt becomes nothing more than a hollow tube, and make a cartridge style valve for the firing valve, that would sit directly inside it. bolt still moves forward to push ball forward and seal firing chamber, but now, there's very little dead volume between valve and ball, plus the bolt gets a lot simpler, as does the gun itself. (aside from finding/designing a valve that'll fit in the bore of the bolt.)
I'll make a drawing of it tomorrow, and go into a bit more detail how I got the ideas. I guess I'm more tired than I originally thought.
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on Jun 27, 2005 21:48:50 GMT -5
left is end view of new idea, not sure if it's worth it or not. instead of a bolt, use something of a larger OD, and with 68 cal ID, cut in roughly half. the basic idea being it doesn't move the ball, only seals the breach. the mass of that can probably be a fair bit lower than that of a bolt. means entire bore gets done out to 3/4, which is a lot easier for me than 11/16, up to the front barrel threads which are bored out larger. (think I'm gonna go with 15/16-20 threads[autococker]) I'd use the other half of the delrin slice as a stationary insert on the bottom half, so the paintball is fully cradled. Any of this make sense? the other ideas I have are a flat sheet style trapdoor that moves forward to close, and a rotary breach that would actually force each shot in. but I don't have a clear picture in my head yet of how the rotary breach would work, so, you get to live without a drawing for now. Anybody have any ideas? :-D oh, and using a gun bore of 3/4 and boring the delrin out to 11/16 doesn't require me to use a lathe :-D, excluding anything I may have to do to make the as of yet not completely designed valve work.
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on Jun 27, 2005 22:09:24 GMT -5
aaand here's the valve. this would be cylindrical in shape despite looking like a rectangle... spring pressure holds the valve closed at all times, and air pressure attempts to push it open, so if the proper spring is used for a given air pressure, it will take *very* little force to open. this is a spring compensated, or spring balanced, poppet style valve (shane grabbed a few books on hydraulics from the UM Flint library and read up on valve design a few weeks ago). It should allow very fast actuation times, on the order of a few milliseconds. plus, after it has opened, and gas begins to flow, that drops the air pressure inside, so there's less force pushing against the spring, so it should close fast too. that's the theory anyway
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on Jun 28, 2005 12:19:02 GMT -5
another idea that came to mind, might not be necessary, but, the delrin for the insert/"bolt" can be bored off center, so it's thinner at the bottom, and thicker at the top where it actually has to hold pressure. only difficulty is that the hole drilled at the fron of the gun for the barrel would have to be drilled off center by the same amount as well
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Post by johnjacobjingleheimerschmidt on Jan 9, 2006 21:08:19 GMT -5
i'm curious what ever happened to this?
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on Jan 10, 2006 10:58:18 GMT -5
still working on it. although somewhat indirectly. starting to make a gingery lathe to do the work I need. and I'm reading through some material so I can estimate necessary valve flow rates for the main firing valve. Also, reading up on designing solenoids, though, I am beginning to doubt that's going to be necessary, and I'll be able to use something off the shelf. So yes, the gun is not dead, and neither am I, even though school is a bitch
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Post by johnjacobjingleheimerschmidt on Jan 10, 2006 12:04:34 GMT -5
hurray! shane's super creative oddity of a brain still works! YES!
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PoeticInjustice
more magical than the magicalest
teh cut3 on3's bitch
My name is Inigo Montoya. You killed my father. Prepare to die.
Posts: 300
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Post by PoeticInjustice on Jan 11, 2006 10:42:44 GMT -5
I don't know about creative, but it's certainly a bit of an oddity.
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