---
publication_id: "OT-2026-000003494"
title: "Keyed Shim Stack for Repeatable Fixture Height"
published_at: "2026-09-15T21:15:19.335012Z"
canonical_url: "https://opentechnical.org/p/OT-2026-000003494"
categories:
  - "tools-tooling"
keywords:
  - "clamp"
  - "wedge"
  - "pin"
---

# Keyed Shim Stack for Repeatable Fixture Height

## Abstract

A fixture is shimmed by a stack of keyed plates that can only assemble in one order, so a height set once is reproduced exactly after the fixture has been stripped and rebuilt.

## 1. Description

## 2. Description

[0001] Each shim (12) carries a key (14) on its upper face and a matching slot on its lower face, and the key is offset differently on every thickness in the set. A stack therefore assembles in exactly one order, and a plate left out leaves the stack visibly unable to close.

## 3. Variations

[0002] For a fixture rebuilt often, the keys may be replaced by dowel pins at different radii, which is faster to machine and reads the same way.