Aicaigou LogoAicaigou LogoB2B WikiIndustrial Encyclopedia

Sine Bar

Updated: 2026-07-24

Overview

The sine bar is a fundamental tool in precision engineering, particularly in metalworking and machining applications. It consists of a hardened, precision-ground bar with two cylinders of equal diameter attached at each end. The distance between these cylinders is precisely known, allowing for accurate angle measurements based on trigonometric principles. Sine bars are essential in tool rooms and quality control departments where exact angular measurements are critical. They are typically used in conjunction with gauge blocks to set up precise angles for machining operations or to verify the angles of manufactured components. The simplicity of the sine bar's design belies its importance in maintaining high standards of precision in manufacturing.

Structure and Working Principle

原装日本进口现货SATO佐藤7630-00 7630-10数显显示精密气压仪深圳市诚信达精密工具有限公司

A sine bar's construction is deceptively simple yet highly precise. The main body is a rectangular bar made of hardened steel, with two cylindrical rollers attached at each end. The distance between the centers of these rollers is a critical dimension, typically 5 inches, 10 inches, or 100mm, 200mm in metric versions. The working principle relies on trigonometric sine function calculations. By placing one roller on a surface plate and raising the other roller to a specific height using gauge blocks, the angle formed between the bar and the surface plate can be precisely determined. The height of the gauge block stack (h) and the distance between rollers (L) relate to the angle (θ) through the equation: sinθ = h/L.

商家经验真实案例 · 安全可信
48.8-49.2孔测量塞规指南
本文介绍48.8-49.2毫米孔径的测量方法,包括塞规选择要点、测量技巧及常见问题处理,帮助用户准确判断孔径是否达标。

Key Features

High-grade sine bars offer several important features that make them indispensable in precision work. The most critical is their exceptional accuracy, with high-quality models capable of maintaining accuracy within 0.0001 inches per inch or better. The precision-ground surfaces and cylindrical rollers ensure consistent, reliable measurements. Durability is another key feature, with sine bars typically made from hardened tool steel or alloy steel to resist wear and maintain accuracy over time. Many models include lapped surfaces for superior flatness and smoothness. The cylindrical rollers are precisely positioned and often made from tungsten carbide for maximum wear resistance and dimensional stability.

Application Areas

Sine bars find extensive use in various industrial and laboratory settings. In machine shops, they're used to set up precise angles for machining operations on milling machines or surface grinders. Quality control departments use them to verify the accuracy of angled surfaces on manufactured components. They're particularly valuable in tool and die making, where precise angles are critical. Other applications include setting up optical instruments, calibrating angular measurement devices, and in research laboratories where precise angular measurements are required. The versatility of sine bars makes them essential in any environment demanding high-precision angular measurements.

Maintenance and Precautions

中矿室内微型吊车 装修搬家小型电动吊车上料履带吊车中矿机械(济宁)有限公司

Proper maintenance is crucial to preserve a sine bar's accuracy. Always store it in a protective case when not in use to prevent damage to the precision surfaces. Keep the bar clean and free from dust or chips that could affect measurements. When using the sine bar, handle it carefully to avoid dropping or striking it against hard surfaces. Regularly check the cylindrical rollers for wear or damage, as any imperfections will affect measurement accuracy. Apply a light protective oil to prevent rust when storing for extended periods. Avoid exposing the sine bar to extreme temperature variations that could cause dimensional changes.

商家经验真实案例 · 安全可信
M120螺距尺寸全解析
本文详解M120螺距的尺寸特点,包括普通螺距与细牙螺距的区别,以及螺距选择对机械性能的影响,助你轻松掌握螺距知识。

B2B Procurement Guide

When purchasing sine bars for industrial use, several factors should be considered. First, determine the required length - common sizes are 5", 10" (imperial) or 100mm, 200mm (metric). Consider the accuracy grade needed for your applications, with higher grades commanding premium prices. Evaluate the material quality - hardened tool steel or alloy steel with carbide rollers offers the best durability. Check for certification of accuracy from reputable manufacturers. For bulk purchases, consider negotiating volume discounts. Always verify the supplier's reputation and ask for references from other industrial clients. It's often worth investing in higher-quality sine bars from established manufacturers for critical applications.

Related Manufacturers