Replacement Cap Nut M60×2.5 for Marimex ProStar Plus 2/4/6 & ProStar 2000 Sand Filter

Replacement Cap Nut M60×2.5 for Marimex ProStar Plus 2/4/6 & ProStar 2000 Sand Filter

A fully parametric replacement for the union cap nut used on the connections of the Marimex ProStar sand pool filter. The same nut repeats in several spots on the filter (4× on mine) — on hose connections, valve ports, with or without an elbow — so one printed part covers them all. A handy fix when the original breaks or goes missing: this version adds a knurled grip and a reinforcing fillet in the corner, and being parametric it's easy to adapt.

Compatible models

Replacement for the original part "Screw / cap nut for ProStar Plus 2, 4, 6 and ProStar 2000". Fits:

Unofficial replacement part. I am not affiliated with Marimex; brand and model names are used only to identify compatibility.

Thread specs

The part has an internal metric thread M60×2.5 (right-handed), verified by measuring the original (4 threads = 10 mm → 2.5 mm pitch).

Features

• Knurled grip around the whole circumference (24 longitudinal grooves) — easier to tighten even with wet hands.

• Fillet in the inner shoulder corner — added a radius in the corner that tends to concentrate stress, instead of a sharp edge.

• Chamfered thread lead-in — starts onto the neck more easily.

• Symmetric lead-ins — the thread is offset from both the shoulder and the bottom, so the transitions stay clean.

Note: I can't claim it's stronger than the injection-molded original — I haven't tested that. It's a functional printed replacement that works on my filter.

Files included

• 3MF (v2.1) — recommended for printing. Correct orientation and scale, ready to slice. Includes my print profile (see settings below), so you can load a proven recipe directly.

• STEP (.step) — precise CAD geometry (not a mesh), for editing in any CAD program.

• FreeCAD source (.FCStd) — fully parametric model. All dimensions driven by a parameter spreadsheet (Params) — easily tweak diameter, pitch, height, grip, or shoulder for a different filter.

Print settings

Printed in PETG (resistant to water, UV and chlorine). The part is intentionally "over-built" — it sits under pump pressure, so better strong than sorry.

These are my settings — feel free to reduce perimeters and infill to save material. It'll still hold.

Tolerance note

The model relies on slight PETG "gain" in FDM printing — the internal diameter shrinks closer to nominal in practice. If the thread fits too tight, increase the radial clearance in the FreeCAD source. I recommend printing a short test ring before the whole part.

Keywords (SK / CZ)

Náhradná matica / náhradní matice, skrutka / šroub, prevlečná matica / převlečná matice pre pieskovú filtráciu Marimex ProStar Plus 2, 4, 6 a ProStar 2000. Náhradný diel / náhradní díl, závit / závit M60×2.5, bazén / bazén, pieskový filter / pískový filtr, šesťcestný ventil / šesticestný ventil.

Feedback

If this part helped you or you have an idea for improvement, drop a comment — I appreciate any feedback and photos from your install.