n00b question for fittings and taps
 

lets say i were to use these for my fittings

what size tap would i need

on and in those measurements...what does the 1/4" signify

http://chicksdigbattlebots.botic.com/tapsizes.htm

I use a 1/4" NPT tap and a 7/16 drill bit for those barbs. I am pretty sure the chart linked will back that up. :D

so on 1/2 x 1/4 npt..the "1/4 npt" refers to the tap size that would be needed to tap a hole? is 1/4" the radius size?

imma have to go back to home depot cuz i asked for a 1/2" npt

i bought a 1/2-14 NPT 45/65 tap...and it dosent fit into my tapwrench, but my tapwrench is capable of handling 1/4"-1/2" taps...im confused:confused:

No, 1/4" NPT isn't directly related to the diameter size. 1/4" NPT means the suggested size of the ID (inner diameter) for that thread type should be 1/4". But we we can get up to 1/2" ID out of a 1/4" NPT thread on a hose barb. When you buy the barbs select 1/4" NPT for the thread and whaterver you need of the ID of the barb. I think 1/2" ID is the biggest barb you can get with 1/4" NPT thread but I maybe wrong. You will have a hard time finding a 1/2" ID 1/4" NPT barb at Home Depot or any standard hardware store. Non of them around here carry anything over 3/8"ID. I found a 1/2" ID 1/4" NPT brass barb at NAPA autoparts of all places though. There is usually a hose place locally that carries such stuff aswell.

Yea, they make bigger NPT stuff. I have been dealing all week with 3/4" and 1" NPT pipes, elbows, reducers, fittings, etc. They make much bigger stuff as well. 95% of you probably can't order from them, but go to www.mcmastercarr.com to search around for all the pipe, barbs, T's, Y's, etc. fittings that they have to get ideas of what is available.

would this be the tap mentioned or this

those dont say "1/2" ID" though:confused:

and what would be the difference between standard and long shank. which would be needed for tapping the waterblock

you need the second tap. standard shank will do, long shank is for deep holes. Isn't nice when the cheaper stuff works out?:)

that 2nd tap is tapered, will it still work with making threads for those fittings?

Tappered is what makes it a NPT thread. I think.

Scratch that, it stand for National Pipe Thread. Which is tappered by default though.

so my second choice would but in suitable in matching the threads that are on those fittings?

my first choice was NPS...national pipe...s sumthing

Yeah, don't use NPS, that is a strait thread with no tapper. If it is a NPT barb (and most we use are) you need to use a NPT tap.

hehe sorry for the horde of questions :)

how would i know how many threads that barb would have per inch

the tap i chose is
Tap Size/Threads Per Inch
1/4"-18

so that means my barb must have 18 per inch, right?

or does it not matter

Yep, and it doesn't really matter. As long as you match a 1/4" NPT threaded part with a 1/4" NPT tap your good.

http://www.so-calspeedshop.com/nos/t...readsizes.html

if you dont mind could you take a pic of a 1/2" - 1/4" NPT tap along side 1/2 ID barb? i just need a quick size comparison

thanks for your help all :)

I can't as the only 1/2ID 1/4" NPT barb I got is being used in one of my systems. :D Surely there are a few that have both laying around. I bet #Rotor might be able to.

all right will do;)

My 5/8" (barbed end) X 1/2" (threaded) have 14 threads per inch. I'm pretty sure the threads per inch have to be the same or else you will get cross threading.

ugh crap...lol

has that happend to you?

No. This is my first system, which is not complete. But I have tried slightly to screw a 14 TPI fitting into a 18 TPI dye. It dosn't work :) nor did I espect it to.

Machine screw sizes:4-40, 6-32, 8-32, 10-24, 10-32 and 12-24


what do those numbers mean?

Don't take my absolute word for it, cause it's been a year since I used the knowledge. But I believe the first # is threads per inch, and the 2nd is the size (you look at a chart to see what actual size the 2nd # translates to, so you know the size to drill the hole).

Someone please correct the cheeseball if he is wrong!

Correcting... The first number is the size, the second is the TPI.

here it is....

12" 1/4NPT barb, then a 1/4" 1/4NPT barb and the 1/4NPT tap...

http://3rotor.homelinux.com/images/m...17_800_sml.JPG