4

I have some sections of 2" PVC and some Tee fittings that I need to join. On the Tee fittings, the main line is threaded and the outlets are smooth. How can I cut the threads in the straight sections to join with the threaded main line?

3
  • 8
    Why do you want to thread the PVC rather than gluing on a 75-cent slip-thread adapter? – Matthew Oct 1 '12 at 16:19
  • 1
    I agree with @MatthewPK - PVC SHOULD NOT BE THREADED! It is to soft. It MUST be glued/clamped. If you are joining PVC to METAL(Copper) use the appropriate adapter. Ring clamp on one side and thread on the other. Costs a few bux but lasts forever! – Piotr Kula Oct 2 '12 at 9:42
  • Fishing pole would be a good application. – johnny Jun 24 '16 at 20:27
22
+200

I see no reason why you should cut threads on a PVC pipe. It seems to me that this would be unnecessarily difficult and would weaken the pipe.

You should, instead, get a slip to thread adapter and glue it onto the pipe to thread it wherever you like. Any big-box hardware store or irrigation department should be able to provide this adapter.

Edit: Here is a link to such an adapter for $1.56at big orange hardware store. :

https://www.homedepot.com/p/Charlotte-Pipe-2-in-PVC-Sch-40-MPT-x-S-Male-Adapter-PVC-02109-1600HD/203825431 enter image description here

2
  • 7
    Or replace the T with a non-threaded version. – BMitch Oct 1 '12 at 16:37
  • Heh, you don't. PVC isn't thick enough or the proper material to be threaded. As is noted, there are glue on fittings specifically for this so don't go making up a kludge that has a high chance of failure. – Fiasco Labs Oct 1 '12 at 17:41
5

Threaded fittings on PVC are intended to connect to existing, threaded NON-PVC connectors, such as galvanized pipe or fittings.

When connecting PVC to PVC it should all be glue joints without threads. You have the wrong type of fitting. Fittings are very cheap, much cheaper than adapters.

3

Need to thread PVC? Use schedule 80.

Schedule 40 PVC pipe is for socket fittings (slip glue) only; threading is not a recommended practice.

Schedule 80 PVC pipe can be threaded.

Cite ~~> http://www.usplastic.com/catalog/item.aspx?itemid=23979

1
  • 1
    Doesn't answer the question of how to cut the threads. – Niall C. Aug 19 '13 at 20:47
1

The thing to look for is a threaded adapter. I searched at my favorite big-box store's web site for both

  • PVC adapter
  • PVC copper adapter

Here is one that is PVC to PVC threads. You glue this one onto the unthreaded PVC, then screw it into the part that's threaded:

enter image description here
Images supplied by lowes.com. No endorsement intended or implied.

and here is one that is PVC to copper. This one is just a push-fit on the unthreaded PVC before screwing into the threaded end:

enter image description here

I didn't find one for 2" pipe, but if your local big-box doesn't have one, I'm sure any reasonably stocked plumbing supply store will have one. They would also know exactly what to get you if you simply asked for "something to connect PVC to a threaded copper pipe".

1

Simple, if expensive.

Use schedule 80 (or heavier) PVC pipe (only.)

Use a pipe thread die and diestock to cut threads, or set up an appropriate lathe with appropriate cutters running at appropriate angles to cut the threads. The die is generally a better choice unless you already own the lathe, know how to cut threads on it (even if they are angled threads) and have sticker shock from the cost of pipe dies but still want to thread the pipe rather than gluing on adapter fittings.

"Simple and cheap" buy and glue on adapter fittings.

This one is from "Supply house .com" is schedule 40 and costs under a buck at the time of writing - but thats not an endorsement, just an example

enter image description here

Better, simple, and cheap - buy Tees intended for glue on all three ports, no adapters needed.

Here's a schedule 40 2" all - glue Tee, and it's under $2. Same source for the picture, same lack of endorsement. Since you'd need two adapters for each Tee, probably a hair cheaper to just get the right Tees for all-glued threadless connections. Certainly less fuss to assemble leak-free, unless there's an unstated in the question need to disassemble by unscrewing.

enter image description here

0

You need a threading wrench (example that may or may not meet your specifications), a clamp, and schedule 80 PVC (I suggest schedule 120 though).

Clamp pvc at 90 degree angle and slowly start threading. You have to keep perpendicular pressure on the wrench so that the threads width is consistent. I took 5-6 practice runs before mine were acceptable. The project I did was for a water pump output for a boat that had to be set up on dock.

I am not really sure why you wouldn't be a threaded piece and just join that with an adapter - which is probably more secure than a self-threaded connection.

Not the answer you're looking for? Browse other questions tagged or ask your own question.