# Caster stem types and sizes: threaded stem (3/8-16, 1/2-13, M10, M12), grip ring 7/16 in, expanding adapter, bolt-hole fitting

> What stem sizes do stem casters come in: 3/8-16, 1/2-13, M10, M12, grip ring 7/16 in?

- Category: Hardware › Casters & wheels
- Kind: Standard part
- Basis: One retailer's stem-caster sizing guide (text and spec sheet) and a Blickle bolt-hole datasheet, read in this session; numbers only
- Page: https://xemstudio.com/objects/caster-stems-threaded-grip-ring/ · JSON: https://xemstudio.com/api/geometry?object=caster-stems-threaded-grip-ring · Plain text: https://xemstudio.com/objects/caster-stems-threaded-grip-ring/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- A stem caster is held to the equipment by a stem instead of a top plate: a threaded stem screws into a tapped hole or nut, a grip-ring stem presses into a socket, an expanding adapter wedges in a tube. Thread sizes the guide lists: UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8; UNF 3/8-24, 1/2-20, 5/8-18; metric M8, M10, M12, M16 (BSF / BSW are mentioned without sizes). Stem lengths are measured from the caster plate or shoulder to the tip.
- Stem diameters printed: 1/4 (.250), 5/16 (.313), 3/8 (.375), 7/16 (.437, grip ring), 1/2 (.500), 5/8 (.625), 3/4 (.750), 7/8 (.875), 1 (1.000) in. The guide says the stem diameter must match the host hole or tube within 1/64 in. It prints no tap-drill, host-hole or socket diameters, so none is given here.
- Grip ring: the guide's table lists 7/16 × 7/8 and 7/16 × 1-7/16 in; its introduction says 7/16 and 1/2 in diameters exist, but 1/2 in is not in its size table. A commonly quoted '7/16 × 1-3/8' size is not on this guide and is not used.
- No file: the shape of a stem fitting (collar, shoulder, grip ring, kingpin) is not defined by published numbers in the sources read. Plate casters are on caster-top-plate-patterns.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| threaded stem | UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8; UNF 3/8-24, 1/2-20, 5/8-18; M8, M10, M12, M16 | tapped hole or nut of the same thread in the equipment | designed | all |
| grip ring stem | Ø7/16 in (11.1 mm) × 7/8 or 1-7/16 in long | socket within 1/64 in of the stem diameter (guide's rule; socket size not printed) | press | all |

## Sizes

| stem type | thread / diameter (inch) | UNF (fine) | metric | length | host |
|---|---|---|---|---|---|
| threaded stem | UNC 3/8-16, 1/2-13, 5/8-11, 3/4-10, 1-8 | UNF 3/8-24, 1/2-20, 5/8-18 | M8, M10, M12, M16 | 1, 1-1/2, 1-3/4, 2 in (from the plate to the tip) | tapped hole in the host; no tap drill printed |
| grip ring (friction ring) stem | 7/16 in diameter (the guide's table; its text also mentions 1/2 in) | — | — | 7/8 in or 1-7/16 in; sizes printed 7/16 × 7/8 and 7/16 × 1-7/16 | precision-fit socket; no socket size printed |
| expanding adapter stem | — | — | — | 1-1/2 to 2 in compressed | tube ID between the compressed and expanded OD; tube sizes 7/8, 1, 1-1/8, 1-1/4 in (and metric) |
| plain round stem and square stem | — | — | — | varies by OEM | — |
| bolt-hole fitting (not a stem) | — | — | Blickle LMDA-TPA 50 and 75: hole Ø10.2 mm, plate Ø41 / Ø55 mm | — | single central bolt |

## Where the files are

- CasterHQ: [Stem casters sizing guide: stem types, thread sizes, stem lengths, grip ring 7/16 in, expanding adapter tube sizes](https://casterhq.com/blogs/caster-university/stem-casters-sizing-guide) — web — Retailer guide; numbers only
- CasterHQ: [Stem casters sizing guide spec sheet (PDF)](https://casterhq.com/downloads/stem-casters-sizing-guide-spec-sheet) — web — Publisher's page; dimensions are facts
- Blickle (via Raptor Supplies datasheet): [LMDA-TPA 50 / 75 castors with central bolt-hole fitting: wheel diameter, total height, plate diameter, bolt hole diameter, offset](https://static.raptorsupplies.com/catalog/product/datasheet/blickle-lmda-tpa-50k-fk.pdf) — web — Maker datasheet; numbers only
- McMaster-Carr: [Casters (plate, stem, bolt-hole) (free STEP/IGES per part, for your own design use; no redistribution)](https://www.mcmaster.com/products/casters/) — STEP, IGES, PDF — McMaster-Carr site terms: personal design use, no redistribution (verify at link)

## Questions

**What thread is a 1/2 in threaded stem caster?**

1/2-13 UNC is the coarse size listed; 1/2-20 UNF is also listed.

**What size is a grip ring stem caster?**

7/16 in diameter, 7/8 in or 1-7/16 in long, on the guide read.

**What stem lengths are common for threaded stems?**

1, 1-1/2, 1-3/4 and 2 in, measured from the top plate to the stem tip.

## Fits with

- [Caster top plates: plate size, bolt-hole spacing, hole diameter and mounting height (Blickle, TENTE, Colson, Albion) + 100 × 85 hole template](https://xemstudio.com/objects/caster-top-plate-patterns/)
- [Leveling feet: base diameter and stud thread (Ganter GN 343.1 / 343.2 Ø25–60, M6–M24; Ganter and McMaster-Carr option ranges)](https://xemstudio.com/objects/leveling-feet-gn-343-and-mcmaster/)
- [Extrusion end feet for 20, 30, 40, 45 mm and 1 in, 1.5 in T-slot extrusion](https://xemstudio.com/objects/t-slot-feet/)
- [Socket head cap screws, M2–M8 (ISO 4762 / DIN 912)](https://xemstudio.com/objects/socket-head-cap-screws-metric/)
- [Hand-truck wheels 8 and 10 in: 4.10/3.50-4 tire, 5/8 in bearing bore, 2-1/4 in offset hub length, tread width and bearing size (maker and distributor listings)](https://xemstudio.com/objects/hand-truck-wheels-8-and-10-in/)