This insert allows you to change the flow rate on a Orbit Saturn III gear drive spray head. These are cheapy lawn sprinker heads available at box stores like HD and Lowes, and on line at Amazon. I was replacing two heads on an existing zone, but the stock nozzle had way too much flow, creating a swimming pool, and causing too much of a pressure drop. There is a set of replacement inserts available from Orbit that have different flow rates, except they are a special order to HD for under $2, but delivery is a week out. Available on Amazon Prime for $6, but its the holiday weekend, and I need to wrap up the sprinkler project so I can enjoy the rest of my "vacation".

Since I was interested in flow reduction, the inserts slip inside the existing stock nozzle as shown in the pics. Target OD is 6.82mm. The nozzle OD has a slight taper to aide in fitting. The fit should be snug but not too tight. There might be danger that if it is too loose, it might get sucked back into the gear drive when the pressure is turned off, but not likely. Once the insert is place, push the entire nozzle back into position. Be careful that it goes all the way in so that when the spray adjust screw is re-installed, the screw does not grab the green nozzle and crush it.

I am done with this project, but it is easy to modify the FreeCAD file. Adjust the nozzle diameter to desired and tweak the Z position of the nozzle taper to leave at least a 0.5mm lip on the exit section of the insert orifice.

This is an obvious candidate for OpenSCAD. One teak in addition to the orifice size is to adjust the exit angle to shoot a higher arc. Can also play with square orifices. The stock nozzle has two nubbies in the exit stream that probably create some close in spray. In my case, I was still seeing over 15ft of throw so I had to use the spray adjust screw to dial back the range which gave ample local coverage. The second possible tweak would be to replace the entire stock green insert with a 3D printed part. I don't think it would have to have as thin a wall sections as the stock piece. There were a number of reviews on Amazon where folks forgot to reinstall the spray adj screw and blew out the GREEN stock nozzle into their green lawns. What was Orbit thinking?

Have no idea how long the ABS will hold up. Printing in Nylon is another possibility, but it soaks up water like a sponge. Don't know about PLA degrading.