This is a customizable twist-off cap or lid, of the type commonly used for glass bottles and jars. On the bottle there are several threads (usually four our six), while the lid is cylindrical, with several "teeth" protruding inside.

Twist-off caps are standardized and come in a fixed set of diameters. These are called TO xx for a cap with xx mm diameter, e.g TO 48 for the 48 mm lids commonly used for dairy bottles. Common diameters include 38, 43, 48, 53, 58, 63, 66, 70, 77, 82, 89, 100 and 110 mm. This is the base diameter of the lid, which needs to pass over the threads on the bottle or jar; so when measring your bottle, please make sure to include the threads in the measurement. The teeth, as well as the threads are usually around 2mm deep. Caps up to and including TO 70 have four teeth, caps starting at TO 77 and upwards have six teeth. As for the height of the cap, there are ordinary and "deep" caps, where ordinary caps are around 9 mm, and deep caps are around 13 or 18 mm.

The model is fully parametric and customizable. The item entry here contains some sample caps. You can adjust the base geometry of the cap, put serrated ridges around the edge for a better grip (set the ridge depth to zero for a plain lid) and put up to three lines of user-defined text on the cap. Leave the text empty if you don't want any. Customize the design here, or download OpenSCAD and make the adjustments there, then render (F6) and export (F7) an STL.

This is probably not an economically interesting item to print, because there are millions of readymade metal caps around - unless you have this one bottle that your really, really need a lid for. But it is useful as a starting point for anything you might want to design around a glass bottle or jar - such as piggy banks, planters, enclosures and so on.

Available sizes

You can generate STLs for any size using the Customizer button here in Thingiverse. Please keep in mind that caps up to TO70 have four tabs, caps from TO77 upwards have six tabs.

I've uploaded a few examples:

• TO48, flat cap
• TO48, flat cap, with serrated edge
• TO58, semi-deep cap, serrated edge
• TO63, deep cap
• TO77, flat cap
• TO100, flat cap, with serrated edge.