Precision inspection squares

Precision inspection squares are used to check perpendicularity. They also support accurate measurement in mechanical machining. They are further used in machine building, construction and woodworking. This group covers several ranges with an L-shaped structure. The manufacturing material is stainless steel, carbon steel or aluminium alloy. The material is chosen according to the working environment. The article numbers comply with DIN 875 with accuracy grades from GG 0 for inspection work to GG II for vocational training.

Surfaces are fine ground or chrome plated, which increases durability and corrosion resistance. Some ranges have a thick base that stands firmly on a flat surface. Versions without a base suit more flexible handling. Besides the 90-degree angle, the group also offers 45-degree squares. The group also offers 135-degree squares. It also offers squares for locating the centre of a circle. Measuring sizes range from 67mm to 1000mm, covering a wide span of workpiece dimensions. The checking method relies mainly on the light gap, which requires a high degree of flatness on the contact surfaces. Vinatools distributes genuine Vogel Germany and ELORA ranges. These are imported goods with clear origin. Vinatools provides warranty according to the manufacturer's terms.

What a precision inspection square is used for

A precision inspection square serves to check perpendicularity between two machined surfaces. The L-shaped structure allows it to be placed flush against the workpiece so the light gap can be observed. The light gap method requires a high degree of flatness on the contact surfaces. This product group serves mechanical machining, machine building, construction and woodworking. Users select according to material, accuracy grade and leg length.

The group brings together ranges from Vogel Germany and ELORA. Surfaces are fine ground or chrome plated to increase durability and corrosion resistance. Measuring sizes run from 67mm to 1000mm, covering many workpiece dimensions. Reference article numbers include 31020- in stainless steel and 31023- in chrome-plated hardened steel.

Classification by manufacturing material

The material directly affects durability and corrosion resistance. Stainless steel resists oxidation well and suits damp environments or contact with chemicals. Hardened carbon steel offers higher hardness but needs storage care to avoid rust. Aluminium alloy reduces weight and is commonly found on models used in carpentry. Granite serves as a reference standard in the measuring room.

The stainless steel group includes 31000 Series, 31002x and 31012 Series. The carbon steel group has 31001x together with 31004x. The aluminium model for carpenters belongs to the 5040- range. The triangular 90° granite version carries the article number 26050-.

Versions with a base and versions without a base

A thick base helps the square stand firmly on a flat surface during checking. This type is convenient when hands need to be free for handling or marking out. Versions without a base are thinner and lighter, flexible when slipped into narrow gaps. The flat two-edge version is also easy to place flush against a workpiece from many directions. The choice between the two types depends on the measuring position and the shape of the workpiece.

Types with a base include 31010- in stainless steel and 31011 Series in carbon steel. Model 31014- is used for inspection work, while 31237- has a thick base with a thin blade. The L-shaped base style appears on 3124 with back. The group without a base includes 1570- from ELORA.

Accuracy grades according to DIN 875

The DIN 875 standard divides inspection squares into several accuracy grades. Grade GG 0 is used for inspection and calibration work in the measuring room. Grade GG I suits checking in the machining workshop. Grade GG II meets the needs of vocational training and practice. Choosing the right grade balances the measuring requirement against the investment cost.

According to DIN 875/0 there are 31010-, 31011 Series and 31001x. The DIN 875/1 standard appears on 31012 Series together with 31004x. The DIN 875/2 standard applies to 3101- and 3100-. Model 31020- follows DIN 875/00.

Measuring angles other than 90 degrees

Besides the right angle, this product group also offers reference squares for other angles. The 45-degree square supports checking of chamfered faces and diagonal joints. The 135-degree square is used when measuring obtuse angles in assembly and interior work. There is also a model for locating the centre of a circle based on a geometric principle. These variants extend the checking range beyond ordinary perpendicularity testing.

The 45° angle belongs to the 3130xx range, available in stainless steel and carbon steel versions. The 135° angle includes 31308x in carbon steel and 1579- with a base. The 35° reference model carries the article number 31408. For locating the centre of a cylinder, use 31254 in Dur-Aluminium alloy.

Selecting by measuring size and working environment

The length of the main leg determines the range of workpieces that can be checked. A short leg is convenient when working in tight spaces or on small parts. A long leg serves checking of frames, large panels and wide timber structures. The thickness and the relief of the square body follow the requirements of the corresponding standard. The buyer only needs to determine the leg length that matches the requirement.

The 67mm to 320mm range is available on 31237- with a chrome-plated base. The 100mm to 1000mm range belongs to 3124 Series in zinc-coated steel. The large 500mm to 1000mm version for carpenters is 52111-. The aluminium range 5040- comes in sizes 150mm, 200mm, 250mm and 300mm.

Sets and models used in vocational training

Some configurations gather several frequently used measuring tools into a single case. This packaging is convenient when moving between checking locations. The group used in practice workshops prioritises surface durability and reasonable cost. Zinc-coated steel meets the conditions of continuous use in a practice room. These models also serve day-to-day checking work in the workshop.

Set 310229 comprises 5 pieces in a dedicated case. The contents include one straight edge, three bevelled-edge squares without a base and one scriber. For workshops and vocational training there are 3124 Series together with 3124 with back. The ELORA range includes 1569- and 1571-.

Notes on use and storage

Checking by light gap requires the workpiece surface to be clean and free of chips. The measuring edge must be protected from impact because even a small deviation affects the result. Carbon steel squares should be wiped dry after use to limit rust. Stainless steel versions withstand damp environments better but still need proper storage. Models supplied with a wooden case protect the measuring edge during storage.

The 31010- range has two options: a plain version and a version supplied with a wooden case. The fine ground surface on 31308x supports accuracy during checking. The chrome-plated base on 31237- increases corrosion resistance. Model 1579- has a hanging hole, convenient for hooking onto a tool rack.

You can filter by material, DIN 875 accuracy grade and leg length to narrow down the options. Contact the technical team if you need to compare the specifications of each article number before ordering.