Thursday, July 28, 2016

Making a Pool Pump ABS Plastic Adapter

Difficulty Level (Easy, Medium, Hard, Insane):

I started noticing more and more air getting sucked into my pool pump and it was getting to the point where half the skimmer was air and the other half was water so I decided to investigate where the air was entering the system.

After taking apart the only three joints between the pool and the pump I quickly found that the ABS adapter that screws right into the pool pump had developed stress cracks letting in the air. Unfortunately, our pool shop had just closed 10 minutes earlier and I wanted to have this taken care of before the end of the night (and I wanted to tinker around in the shop) so I decided I was gonna make use of a piece of 4" ABS I had in my stash along with my metal lathe which I hadn't used for some time.

The process was fairly simple and cutting the ABS was really easy on the lathe. The only issue was that I accidentally made one of the walls too thin (0.056" instead of 0.100") and had to chuck the part in the trash because it was flexing and ripping. That was a bit of a bummer, cost me 4" of the ABS and about 90 minutes but I did learn another valuable lesson: leave enough "meat"!

The second part went quite a bit quicker. Here are the steps I followed:

1. Cut 4" of 4" diameter ABS on my Metal Band Saw
2. Chuck the ABS and face one side
3. Turn it down to 3" for the last 0.750" closest to the head stock
3. Turn it down to 1.500" for the next 1.500"
4. Turn it down to 1.375" for the last 1.500"
5. Drill a hole to 1.000"
6. Flip it around and bore it to 1.250" for about 2.000" deep
7. Bore it to 2.000" for about 0.500" deep
8. Cut an o-ring groove 0.100" from the outside diameter, 0.080" deep and 0.100" wide
9. Flip the part around and taper both stages with a 2.5 degree angle

Now I have a very solid replacement ABS adapter that will never break again. EVER!


The pool adapter
Close-up of the cracks that developed (center picture)
Back side of adapter with o-ring groove
Cutting the ABS on the metal band saw
Facing the piece
Turning it down to size
Drilling at 1.000"
Some of the "chips"
Boring the inside (this is where I went too deep)
Cutting the o-ring groove
With the installed o-ring
Turning down to size
Cutting the taper
Second try
Back side of the second version
I accidentally dropped the o-ring and didn't notice it until about an hour later. I was so glad I found it (top left of picture)
O-ring on top of the ABS "chips" to demonstrate how it would have been impossible to find if it hadn't fallen down to the side
Close-up of the installed o-ring
The new adapter with the threaded ring
Back side of the adapter

Metal lathe & accessories
Metal band saw

4" of 4" diameter ABS


3 hrs


Works great and is really solid


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