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Member Since 17 Jan 2010
Offline Last Active May 18 2016 12:04 AM

Posts I've Made

In Topic: Etek 4 or Ego9?

16 September 2012 - 01:18 PM

Thanks for the reply. I can definitely live with a simple LED board. After reading through the Etek4 manual, it seems like a breeze to program, compared to a TM-15. I was just a little curious whether an LCD screen is really worth getting over SL3 HP and LP regs, S4 barrel, and Zick 2 rammer.

In Topic: Physics Experiment

23 May 2012 - 08:42 AM

A possible alternative to the first method involving a skateboard is to shoot at a hanging target, hung by a thin string.
taking into account the weight of the target and measuring the difference in height of the target as it is shot, you can use the same momentum method to find the paintball's force.
i'm trying to think of a method for measuring pressure in front of the bolt. i'll edit this post with that information later; my laptop battery's about to die.

In Topic: Lightest Possible Material for Rammers

19 November 2011 - 04:18 AM

Do it! Posted Image

While I've repaired press and shrink fit bushing on helicopters, I've never actually made them. If you do manage to get some machine time, I'd be really interested in seeing pictures of the manufacturing process.

HAHAHA i'd be more than willing to make time to made one if you supplied a planet eclipse ego for me to tinker with. and likely keep :D
as for the manufacturing process, it could simply be made on a manual lathe. though probably not as accurate as a properly programmed CNC lathe, i reckon one could get it pretty close if patience and effort was put in.

you'd probably get more thrills out of watching lathe videos on youtube than seeing how i could have made this.

In Topic: Lightest Possible Material for Rammers

18 November 2011 - 01:00 AM

6061-T6 aluminum alloy already has a strength (tensile yield strength; the maximum tensile stress before permanent deformation) greater than common A36 steel. The forces that act on paintball gun components are relatively minuscule, compared to what some of these materials are used for. For example, the link for the A36 steel mentions that the material is commonly used for guardrails. Selecting a material used for stopping cars might be overkill for paintball mechanisms. For example, the air tanks generally don't contain more than a maximum of 6,000 psi (this is on the extreme side); 6061-T6 has a strength to withstand 30,000 psi (shearing motion) before failure.

My purpose here isn't to dissuade you from manufacturing your described rammer, but rather to introduce the question "what exact material properties are required for the rammer?" If you only need something to withstand a maximum of 6,000 psi (you'll need to calculate the forces experienced by the rammer for a truer number)... maybe the answer is literally right in front of you.

Another thing to think about, from a purely manufacturing standpoint, is how are you going to combine the aluminum casing with the other steel components? If you're wanting to assembly them in a press fit or shrink fit manner, you're going to need extremely tight tolerances (like on the range of +/- 0.0001"). On the other hand, if you're going to use adhesives, then you're going to need to take the addition mechanical properties of the adhesives into account (e.g., will the glue hold under cyclical stresses).

oh, shame on me, i just had a course in material science last year, and have a closely related manufacturing processes course this year. i just really didn't feel like digging through data sheets and text books after a long day in classes =P

as i've mentioned before, i simply have an excess of 0.5" aluminum rod. around 7 feet excess actually. also, as mentioned, i don't have such a marker to make such part for. not that i really have any extra time in the machine shop to fabricate such a part anyways.

but to address the issue of combining aluminum casing and steel; i was thinking of making the steel cap shaped like a mushroom, press fitting it into the aluminum casing, then turning down the casing to a final outer diameter if it expands from the steel insert being forced in.
i've done a remotely similar process in last year's project; press fitting a brass bushing into an aluminum block, then boring out the inner surface of the bushing to allow a lead screw to pass through. keep in mind i wouldn't have had to bore the bushing out if my partner turned the bushing down to the right outer diameter properly in the first place.

another option would be to make an insert/cap that threads into the casing- probably easier to do, but hey, we're being to taught to consider multiple options :)

In Topic: Lightest Possible Material for Rammers

17 November 2011 - 07:54 PM

for the sake of only making a lighter rammer with some strength:

completely hollowed out aluminum bored with harder (steel?) end caps/inserts to strike the valve stem.
i guess you could go lighter by using a composite bore, but it might eventually deform around the solid steel end cap/insert.

if i had a stacked tube electropneumatic marker and lots of spare time, i might be able to whip up one such rammer. someone mistakenly ordered 8ft of 6061-t6 aluminum rod for our project group instead of 30 inches.