O Ring Guide - James Walker - #3

How to use this guide

This guide contains three chart sizes:

• Chart 50 -including BS1806 and SAE AS568A.

• Chart 72 -metric sizes to BS4518.

• Chart 17000 -James Walker inch sizes.

If your existing 'O' ring has a BS1806, SAE AS568A or BS4518 reference:

1. Refer to Chart 50 for BS1806 and SAE AS568A, or Chart 72 for BS4518.

2. Quote appropriate James Walker number.

Contact our Technical Services Team. We have in excess of 8000 'O' ring moulding tools in our library and are sure we can help.

One or more back-up rings are used to prevent extrusion of an elastomeric 'O' ring under arduous operating conditions. Our standard back-up rings are machined in PTFE and normally supplied in single turn or spiral form. See page 10 for more details of back-up rings.

1. Refer to diagrams on page 28.

2. Select the one that matches your housing.

3. Obtain from existing housing the critical dimensions shown on selected diagram.

4. Refer to Housing Tables 7 & 8 on page 26. These show BS1806/SAE AS 568A in both inch and metric units, and BS4518 (metric) with more data on pages 18-20.

5. Cross reference dimensions on housing tables.

6. Read off diameter section A, and consult appropriate JW chart under that specific diameter section.

7. Refer to column that shows housing diameter (coded as selected diagram on page 28) and identify the one that matches yours.

8. Quote appropriate James Walker number.

1. Refer to Design notes section, pages 24-28, for guidance with regard to applications.

2. For metric equipment, select 'O' ring from Chart 72, pages 18-20.

3. If the metric size you require is not available from Chart 72, then select from metric columns in Chart 50, pages 11-17.

4. For inch sizes use Chart 50, or Chart 17000 on pages 21-22.

Refer to How to order section on page 5 for precise specification details relating to back-up rings for Chart 50, Chart 72 and Chart 17000 applications.

1. Identify appropriate JW chart and James Walker number for existing 'O' ring. If necessary, use method outlined on this page in To match an existing 'O' ring.(Note: If a standard 'O' ring has been used on a non-standard shaft or cylinder - ie, compressed or stretched into place - the equivalent standard back-up ring must not be used as it cannot be stretched or squeezed in the same way.)

2. Refer to How to order section on page 5 for precise specification details.

Contact our Technical Service Team who will recommend the correct back-up ring.

1. Select the 'O' ring you require from JW charts, using method outlined on this page.

2. Refer to How to order section on page 5 for precise specification details.

1. Obtain diameter section A of 'O' ring .

2. Consult Table 1 (above) to find the JW chart that covers rings of the appropriate diameter section A.

3. Consult appropriate JW chart, under specific diameter section A.

4. Obtain inside diameter B of 'O' ring.

5. Refer to column on JW chart that lists inside diameters B and identify your existing 'O' ring.

6. Quote appropriate James Walker number.

*-B-►

t I

3