ZTC Stackable Lens Tubes

ZTC lens tubes provide an open cylindrical housing with mating internal and external threads for mounting optics and building removable tube assemblies. This documentation covers all 38 online SKUs. An explicitly labeled millimeter table supports 37 entries, and a separate drawing covers ZTC-1-6.0. Thirty-three dedicated images identify individual models and their internal-thread depths; the five SM4 options rely on the general table. Choose the complete thread interface first, then check bore clearance, optic thickness, retaining rings and available axial space. Tabulated length, internal-thread depth and overall length are kept distinct. The source identifies aluminum alloy and a black oxidized surface without specifying a grade or process rating. English artwork illustrates the family structure and does not replace a model-specific engineering drawing.

Joining tubes and mounting optics

ZTC tubes have an open bore, an internal thread at one end and an external thread at the other. The source shows removable threaded connections and retaining rings for locating optics. Thread engagement affects the axial length of a joined assembly, so tabulated tube lengths cannot simply be added. Pictured lenses, rings and adapters do not establish the contents of a supplied kit.

Interfaces and dimensional table

The general table defines A as outside diameter, B as the threaded opening, C as bore diameter and L as length. Its 37 entries explicitly use millimeters. Distinguish SM0.5, labeled SM05 in overview images, from SM1, SM2, SM3, SM4 and SM30 by their complete thread specifications. SM30 is M30.5 × 0.5 and is not interchangeable with SM1. Interface names, optic diameter and clear aperture are separate specifications; check optic thickness and retaining-ring clearance.

Length definitions and the long SM1 model

The 33 dedicated images explicitly call their axial values internal-thread depth. A general schematic separately labels overall length as L+3.8 and an external-thread segment as 3; tabulated L is not renamed overall length. ZTC-1-6.0 has its own drawing. Its photograph explicitly gives a 152.4 mm internal-thread depth, while the separate drawing has no visible unit note and differs from the general SM1 table. Do not transfer the standard SM1 bore or overall-length relation to that model.

Materials and ordering checks

The source identifies aluminum alloy and a black oxidized surface but specifies no alloy grade, oxidation process or coating rating. White, purple and similar selector words are not verified finish choices. Five SM4 models have no dedicated image; their dimensions rely on the general table. Check thread fit, permitted clamping force, optic edge geometry and axial clearance. Load, sealing, stray-light suppression, machining tolerances and ring or accessory quantities are not fully specified.

Selection checklist

Match the complete thread specification

Keep table length, thread depth and overall length distinct

Check optic edge, thickness and retaining-ring clearance

Confirm drawings, tolerances and supplied accessories

To be confirmed

Alloy grade, oxidation process and coating rating

Tolerances, load, clamping force and optical performance

Dedicated SM4 images and unit note for the separate ZTC-1-6.0 drawing

Rings, optics, adapters, quantities and delivery