Cylinder Top Screw: What It Does and How to Fit a Replacement
By Penile traction device for Length & Curvature | Published: 2026-11-02
Category: How-to Guides
Learn what the cylinder top screw does in a penile traction device, spot a loose or stripped screw, and fit a genuine Sizegenetics replacement in a few careful steps.
Quick answer
Replace the cylinder top screw only when the old one is loose, stripped, or missing, and fit the new screw with the device fully unloaded so the threads seat straight. If tension still slips after tightening, stop and check the rest of the cylinder assembly before assuming the screw is at fault.
What the cylinder top screw actually holds together
The cylinder top screw sits at the top of the cylinder assembly, where the traction force is transferred from the rod system into the cylinder. It is a small part with a narrow job: it keeps that top connection secure so the assembly can hold the tension you set.
Because it is small, it is also easy to overtighten or cross-thread. A screw that feels loose may simply need reseating, while a screw that spins without tightening is usually stripped and needs replacing. Treat those as two different problems rather than tightening harder.
When to replace rather than retighten
Retightening is the right first move if the screw still bites and the assembly holds tension afterward. Replacement makes more sense when the screw head is damaged, the threads no longer grip, or the screw is missing entirely.
If the device loses tension even with a new screw seated properly, the cause may be elsewhere in the cylinder assembly or the rod system. In that case, inspect the whole setup before ordering more screws.
How to fit a cylinder top screw step by step
- Unload the device completely: Remove all traction tension and take the device off before touching the screw. Work over a tray or cloth so a dropped screw does not disappear. Never fit a screw while the device is under tension; the threads can cross under load.
- Remove the old screw and check the threads: Back the old screw out slowly and look at both the screw and the hole in the cylinder top. If the hole looks damaged, do not force a new screw in. A damaged receiving thread needs attention before a replacement screw will hold.
- Seat the new screw by hand first: Turn the new screw in by hand until it sits flush, keeping it straight rather than angled. It should turn smoothly with light pressure. If it binds within the first turn or two, back it out and restart rather than pushing through.
- Tighten just enough to hold: Finish with a light snug turn, not a hard crank. The screw needs to hold the top connection, not compress the assembly. Stop at snug; overtightening is the most common way to strip a small screw.
- Test under light tension before a full session: Reassemble the device and apply a low tension setting first. Check that the screw stays put and the assembly does not shift before returning to your usual setting. If tension slips at low load, recheck the seating before using the device again.
Replacement part facts
- Cylinder top screw: This cylinder top screw is a genuine spare part for Sizegenetics penile traction devices and is available as a left and right pair. Ordering the correct side and keeping a spare on hand means a stripped screw does not sideline your routine while you wait for a replacement.
Cylinder top screw
