Technical Dimensions

Choosing the right air shaft or adapter starts with taking a few key measurements correctly. This page explains what each measurement means and how to take it.

Core inner diameter (inches)

Air shafts are named after the inner diameter of the core they carry; a “3-inch shaft” or a “6-inch adapter” refers to this inner diameter. Always measure the inside of the core, not the outside. If the end of the core is crushed or out of round, measure an undamaged core for a more reliable figure.

Shaft length

Two lengths matter: the overall length from end to end, and the body (working) length on which the cores sit. If you are replacing an existing shaft, give both measurements separately.

Journal dimensions

The journal is the end section of the shaft that sits in the machine or in the safety chuck. For each end, measure the diameter, the length and, where present, the square section, keyway or any steps; the two ends are not always identical. Because journals are machined to the customer’s drawing, a technical drawing is the most reliable reference if you have one.

Dimensions to include in a quotation request

• Core inner diameter (inches)
• Overall length and body length
• Dimensions of both journals, or a technical drawing
• Roll weight and quantity

Standard and special sizes for each product are shown in the summary table below. Some values appear in different forms in older sources and are therefore both shown in the table; final values are confirmed at the quotation stage. You can send us your dimensions through our contact page or browse our air shafts.