riser pipe threading

It seems that I need to "adjust" some of my mister heights due to landscape modifications.
Since most of my adjustments would be to heads in shrubs, and they would be to LOWER the heads, I wish there were a way to simply cut and re-thread the riser.

Since the risers are made of soft plastic I think that I could re-thread them w/o removing them from the line. That would make it so much easier (no digging or dirt in the lines, etc).

My problem is I can't seem to find any internet references to how to thread those items or any "dies" what would be used to do the threading.

Could I just use an NTP or BSP 1/2 inch pipe die?

Also why wouldn't this be a common practice for the professional installers?

Well the cost to just replace a 50 cent nipple with a shorter one, compared to the cost of pipe dies, etc, is just ridiculous. First, you could not thread them in place ( no way to properly hold back the nipple.) You would have to dig them out anyway.

nipple alternative

Thanks for the quick comeback, Jimbo!

The problem is that many of the risers are simply 3 ft "long" nipples in the middle of shrubs. That creates two problems. First depending how deep the feed piping is, you probably have to dig your way to the tee to reattach the new pipe. Second, in Florida, and maybe else where, near shrubbery the root system can become horrendous. Digging down to the feedline tee could take all day.

I could possibly (as suggested on the internet) just cut off the riser at the proper height and glue on a pipe-to-thread nipple or simply reuse the existing cut off piece (although shorter) and glue a coupling between the cut. The problem with that is I have problems finding Sched 80 (gray) fittings and the others are Sched 40 and are conspicuously white.

I've also read that the PVC is so soft, someone said that they sometimes thread the pipe by hand. So I don't think it would be too difficult. You can thread Sched 80 because its thicker.

Yes, I bet the pipe die would cost a bit, and wondered if there were a cheaper one for PVC use.

Cut the pipe off then glue a male adapter to it. I have never tried to thread PVC, but there is no reason to when cutting and pasting is so quick, easy, and cheap.

Pvc

It is possible to thread PVC, but sometimes you need dies with a special rake to avoid tearing them.