Centering Holes

Build a homemade water gun or water balloon launcher and tell us about it.
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soakernerd
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Centering Holes

Post by soakernerd » Tue Mar 23, 2010 3:51 pm

I have developed a method for creating a perfectly centered hole in an endcap, without measuring or using a drill press.

Materials:
PVC endcap
Washer that fits snugly within the endcap
Drillbit that fits inside the washer

Simply place the washer in the endcap, and drill through the center of the washer. if you need your hole to be larger, you now have a perfectly centered pilot hole.

This greatly simplifies creating perfect nozzles with PVC endcaps.

Q? C? F?

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martianshark
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Re: Centering Holes

Post by martianshark » Tue Mar 23, 2010 6:18 pm

Sounds like a good idea to me. I don't really care about centering that much, but if I happen to have a washer the next time I'm drilling, I'll use it.

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C-A_99
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Re: Centering Holes

Post by C-A_99 » Tue Mar 23, 2010 8:03 pm

This sounds like an interesting method. The tricky part is finding a washer that fits well into the cap, as well as has a hole the correct size. In this case, it may be possible to place the washer so that it is level in the endcap (if the washer is smaller), but it's kind of tricky and eye-ing out the center would probably be just as reliable. Regardless of which method you use, marking the center usually helps quite a bit if it's marked well.

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JuchTurtles
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Re: Centering Holes

Post by JuchTurtles » Wed Mar 24, 2010 1:29 am

That's conveinent! Only problem is finding washers with dfferent IDs (inner diameters) for different size drill bits.
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C-A_99
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Re: Centering Holes

Post by C-A_99 » Wed Mar 24, 2010 1:37 am

And the other problem is finding washers with the right OD for the cap you're drilling. (oh wait, I just mentioned that; please read previous posts before basically posting a one-liner repeating what someone else mentioned, thanks)

I forgot to mention this though: when drilling a new endcap the other day I noticed that the center of the cap on the inside is a little bit flat; a small, circular flat area. This should be the absolute center more or less (depending on how percisely the caps were manufactured), and I've found it to be a good reference point for marking the center to drill. Unfortunately, you can't get it perfect every time or even most of the time, but if it's very close to the center it doesn't really matter anyway, as far as pump caps go.

Nozzles on the other hand, require precision which cannot be gotten from a drilled endcap nozzle and for that reason, I suggest using water balloon fillers or hose barbs for nozzles. (there are also small conical garden hose nozzles available made from metal) However, if you have a nozzle laminator, you may be able to get decent streams from an endcap. Personally I find the water balloon filler more worth it since I got close to CPS 2000 range (can't remember if it was more or less) with just a water balloon filler nozzle that's roughly 6mm. The lamination is excellent from this nozzle and the PC is considerably less powerful than the CPS 2000's.

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soakernerd
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Re: Centering Holes

Post by soakernerd » Wed Mar 24, 2010 1:54 am

yeah, finding the right washers is annoying. I just happened to have the right size for a 3/4" endcap with me (1" washer) , and I noticed they fit perfectly. While the odds are low that you have washers that fit, if you are buying parts from Home Depot, you can easily pick one up for ~.25$ (25 cents).

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martianshark
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Re: Centering Holes

Post by martianshark » Wed Mar 24, 2010 3:55 am

Like CA_99 mentioned, I highly recommend using sweep nozzles from Home Depot. They give a great stream that has high output and spreads slightly as it travels. They also work as water balloon fillers.

When using actual water balloon fillers, make sure that you don't use the cheap kind with plastic hanging off of it from the mold. It turns it into a sort of small riot blast.

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C-A_99
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Re: Centering Holes

Post by C-A_99 » Wed Mar 24, 2010 6:05 am

I've never heard them called sweep nozzles (maybe I simply didn't pay attention), but they are indeed useful for water balloon filling. I went with hose barbs as nozzles for my VHS and while they work nicely, they're not as good as conical nozzles and are a bit trickier to fill balloons with. (I used 3/8 barbs) I prefered sticking to plastic to keep costs down and because the VHS will be stored indoors, but on a hot day, pressure can build up and one of my VHS's tees got destroyed from this. (everything else was intact) Despite that I still didn't go with a metal solution for that part.

For water balloon fillers, your mileage will vary. Some are manufactured all nice, percise, shiny, and fancy while others may be put under a poorer moulding process. For those that are not so great, chances are that you can simply remove any excess plastic from the mould, but whatever you do, do not drill them. The drill makes the plastic rough and you will end up with terrible stream lamination and range.

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martianshark
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Re: Centering Holes

Post by martianshark » Wed Mar 24, 2010 7:22 pm

That's what the lable said - sweeper nozzle. It's meant for sweeping sidewalks using a hose.

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