Pipe Tapping

[frogy]

I know there's like a million posts on this already, but I need a thorough response...

I need to tap my 1/4" MIPS x 3/8" barb fitting into my sprinkler valve... It is very easy for me to do this by drilling a 1/2" hole and threading it in....

But, when I try to thread in my 1/8" Schrader and 1/8" gauge all they do is spin out of the hole sideways and ruin my test pipe...

There's no way in hell I'm going to spend $20 on a fucking pipe tap, just the idea of someone doing that is retarded...

What is an economical way to tap pipe without fucking it up?

my 3/8" Barb wont fit into my drill chuck very well either, but I call still do that.

1/8" holes are the problem.

[huse_spud]

i put in a 1/4 hex nut in by hand to tap it then i used teflon tape. and there were no leaks and i placed it in almost perfectly straight.

another time i bought a tire valve that had a rubber seal on the end so i inserted it thru the inside of the endcap and put the other rubbber seal on the other outside and secured it with a nut.

[frogy]

I already glued my chambers up, and I already bought a Schrader that taps in from Joel.... whenever it gets here I'll try to thread it...

My nextdoor neighbor is a plumber at my dad's house so I'm really hoping that he has a 1/8" - 27 thread pipe tap that I can use....

What size hose do I need to drill is what I really need to know.. Joel says 11/32, but that's way too small when I try, the fitting just starts turning sideways...

[huse_spud]

hose, your talking about sprinkler valves right? i think there is a tutorial in general spud cannon section i think. i wouldn't want to give you bad info becuz ive never used hose be4.
i just had a hex nut attached to a blowgun on my first sprinkler.

http://www.spudfiles.com/forums/viewtopic.php?t=305

or did u mean what size hole?

in that case take an extra piece of scrap pvc pipe, drill holes and see what works.

i have a piece of scrap cellular core that i use.

[frogy]

I'm using a 2.5" long 1" diameter nipple that I cut wrong for my test peice.... lol it's 2.5" long and has like 15 holes in it, some 1/2", some 11/32", I'll try something bigger than the 11/32" and maybe it will work right, I'm still hoping my neighbor has pipe taps that I can use though.


Joel says drill an 11/32" hole to thread in the 1/8" NPT Pop-off valve that he sells...

I'm drilling an 11/32" hole and I can't thread in my 1/8" NPT Hose Barb into my test pipe.

The 1/8" NPT Hose barb isn't for my sprinkler, it was a part that I accidently ordered and now I'm using it to test how to thread my 1/8" NPT Schrader and 1/8" NPT 100 Psi gauge once I get them from Joel.

[huse_spud]

ok got it. good luck with that.

u can get a signature now at the store if u want.

[spudshot]

what store are you shopping at? 1/8" npt taps are about 4 bucks here, just pick one up and do it the right way.

[huse_spud]

spudshot's right.

[Shrimphead]

For my pressure guage, I just found a drill bit just a little smaller than the threads, drilled the hole, then twisted the guage in. Then I pulled it out, epoxied it, and turned it back in. Worked just fine for me.

[frogy]

I'm think my neighbor has pipe taps, he's a plumber so he most likely does...

If not I found that:

3/8" Drill bit works well for pre-drilling for 1/8" NPT threads

1/2" Drill bit works well for pre_drilling for 1/4" NPT threads


I thread my stuff in a vise so it's steady and it looks like I used a pipe tap... I threaded my 1/4" barb 4 times and my 1/8" barb about 7 times so I've got the hand of it and the holes look perfect now... But If my neighbor has pipe taps I'll still wait for thoose...

[CS]

I can get both 1/4" and 1/8" taps for 2.50$ each. Shipping is like a buck... If you want me to shuttle you it, I can. Problem with threading with fitting is that they most likely "stretch" the plastic rather then cut it. Not to mention that a tap cuts the thread slightly undersized so that its a tight fit, but I guess that could always be countered by teflon.

[drac]

You remedy the tightness by threading the tap in farther, but not so it's loose.

[spudshot]

you want it to be tight, it is tapered after all, plus, you should use drill bits 5/16" for 1/8" NPT and 7/16" for 1/4" npt

[frogy]

I found out my step-dad bought a tap and die set and it had one NPT tap and it happened to be 1/8" so I used that....

But I'm still just going to hand-thread my sprinkler valve if my neighbor doesn't have a tap, I know what I'm doing now.... or atleast I think so