# 17 mm ball joint for phone mounts (ball stud)

> What size is the ball on a car phone mount?

- Category: Everyday mounts › Adapter blocks
- Kind: Hardware
- Basis: The 17 mm ball is the de facto size of car and bike phone-holder ball joints, as named in maker listings (e.g. OOKWE's universal 17 mm ball head vent adapter) and community socket sets; no maker publishes the socket
- Page: https://xemstudio.com/objects/phone-mount-ball-17mm/ · JSON: https://xemstudio.com/api/geometry?object=phone-mount-ball-17mm · Plain text: https://xemstudio.com/objects/phone-mount-ball-17mm/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); linked files under their publishers' licenses
- 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 printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part.

## Notes

- Most clip-on car phone holders, vent clips, dashboard and suction bases join with a Ø17 mm ball on the base and a split socket with a screw collar on the phone head.
- File: a ball stud with the Ø17.0 ball (the interface) on a Ø8 neck and a Ø20 × 4 foot. The neck and foot are my design, to union onto your own base (a clamp ring, a vent clip, a plate).
- The socket side (its split, the collar thread and the cup depth) is not published by any maker I found and is not drawn. A socket is sized to grip Ø17.0.
- This is not the 1 in (25.4) ball of RAM-style B-size mounts: see ram-mount-ball-sizes.

## 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 |
|---|---|---|---|---|
| ball | Ø17.0 | phone-head split socket with a screw collar | socket | ball-stud-* |

## Sizes

| feature | mm | from |
|---|---|---|
| ball | Ø17.0 | maker listings (OOKWE), community socket sets |
| neck | Ø8 | my design |
| foot | Ø20 × 4 | my design |
| socket, collar thread | not published | — |

## Where the files are

- OOKWE (listing by Walmart): [Car air vent mount clip adapter, universal 17 mm ball head](https://www.walmart.com/ip/945843992) — web — reference (verify at link)
- MakerWorld (community): [Ball joint socket set for phone mounts (17 mm), described as the industry-standard 17 mm ball system](https://makerworld.com/en/models/3070848) — STL/3MF — varies per upload (verify at link)

## Free STEP/STL (1 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/phone-mount-ball-17mm/index.json

- ball-stud-17: [STEP](https://xemstudio.com/files/hardware/phone-mount-ball-17mm/ball-stud-17.step) · [STL](https://xemstudio.com/files/hardware/phone-mount-ball-17mm/ball-stud-17.stl) — 17 mm ball stud: Ø17.0 ball on a Ø8 neck (neck 6 clear below the ball) on a Ø20 × 4 foot; ball centre 17.500 above the foot face. Ball exact; neck and foot are my design

## How it fits

### Goes in or on
- [Handlebar clamp rings: split rings for 22.2 to 35.0 mm bars, M4 / M5](https://xemstudio.com/objects/handlebar-clamp-rings/): union onto a bar clamp
- [Car air vent slats: thickness range for vent clips](https://xemstudio.com/objects/car-air-vent-slats/): on a vent clip

### Alternatives
- [RAM-style mount ball sizes: A 0.56, B 1, C 1.5, D 2.25 and E 3.38 in](https://xemstudio.com/objects/ram-mount-ball-sizes/): 1 in RAM-style B ball for heavier heads

## Questions

**What size is the ball on a car phone holder?**

17 mm on most clip-on and vent phone holders; the phone head's socket grips the Ø17 ball.

**Is the 17 mm ball the same as a RAM ball?**

No: RAM B-size balls are 1 in (25.4 mm). See ram-mount-ball-sizes.

**Can I put a 17 mm ball on a bike bar?**

Yes: union the stud onto a handlebar-clamp-rings ring for your bar Ø.

## Fits with

- [RAM-style mount ball sizes: A 0.56, B 1, C 1.5, D 2.25 and E 3.38 in](https://xemstudio.com/objects/ram-mount-ball-sizes/)
- [Handlebar clamp rings: split rings for 22.2 to 35.0 mm bars, M4 / M5](https://xemstudio.com/objects/handlebar-clamp-rings/)
- [Car air vent slats: thickness range for vent clips](https://xemstudio.com/objects/car-air-vent-slats/)
- [Camera tripod thread bosses: 1/4-20 UNC and 3/8-16 UNC](https://xemstudio.com/objects/camera-thread-bosses-1-4-20/)