Alittle help with NPT,NPSI Comparison

If you're looking for a skip tooth tap NPT that you can easily drive , I have a few . Just drill and tap . Do yourself a favor and buy a gage . Hydrotesting gone wrong = trouble . As far as reamers , the big boys use them .

Edit . I read you have an interupted cut tap which I'm assuming is a skip tooth . You'll have no problems with that depending on lathe size of course .
 
Thanks again for all the input guys. I ended up finding a good deal on some nos butterfields so I have plenty now.
Now my thoughts have gone to the hole. 23/32 hole some of these flanges are 3” thick thinking about annular cutter verses a drill. I got two new bits for it but I’m thinking of getting a carbide annular cutter and see how she does. As for reaming I did read about it but I don’t see a need for it. I could be totally wrong and I will find out.
As far as gauges yeah I’ve been looking. If I find a good deal I’ll get it but from two different fitters I’ve been told how they check is run the pipe/plug in to just seat the fitting. Then back out the pipe/plug counting turns. It should fall in your hands at 4 1/2 turns. That’s what I’m gonna gauge it off of.
These flanges range from 6” to 25” in diameter and 1-3” thick. Someone said lathe my plan is the Bridgeport for what I can lift on there and the big boys are gonna get a mag drill. The friend suggested the mag drill he says they usually make them using a hand drill and muscle, but not this quantity and their swamped. From what he’s saying this could be consistent but not frequent. Will see how she goes.
 
Just buy the proper tap, the charts call for a drill size of 23/32. Start the threading on the lathe and finish by hand to the required depth.
Keep checking the thread depth with a 1/2"pipe nipple till you about 4 threads from the thread end. Buy a quality pipe nipple no Chinese junk as their treading is notoriously bad. Be sure the blind flange is thick enough for full threading.
You could also drill and then weld a 1/2' threadolet to the flange. But your welding skills will have to be good.
 
You are going to need a big tap wrench... the reamer will reduce the torque a little.

Sent from my SM-G892A using Tapatalk
 
You must log in or register to reply here.
Back
Top