What Is The Same?
The product threads in ISO-7 and BS-21 and EN-10226 are identical and fully interchangeable.
What Is Different?
The screw thread gage design is different. Here is a listing of the available gages for each specification:
BS-21:1985; Page 10; Appendix A. Recommended gauging systems for joining threads.
Paragraph A.2. System A - Figure 7. Rc-series Tapered Full-Form Screw Thread Plug Gage
- Figure 8. R-series Tapered Full-Form Screw Thread Ring Gage Paragraph A.3. System B - Figure 9. Rc-series Tapered Full-Form Screw Plug Gage - Figure 10. R-series Tapered Full-Form Screw Ring Gauge - Figure 11.0 Rc-series Tapered Plain Plug Gauge - Figure 12. R-series Tapered Plain Ring Gauge
ISO-7-2:2000; Page 29; and EN 10226-3:2005 Page 34; Annex A Summary of gauges; Figure A.1: - Gauge No. 1 - Taper Full Form Threaded Plug Gauge
- Gauge No. 2 - Taper Full Form Threaded Plug Gauge with Relief
- Gauge No. 3 - Parallel Full Form Threaded Ring Gauge - Gauge No. 4 - Taper Plain Ring Gauge - Gauge No. 5 - Taper Modified Thread Form Check Plug Gauge - Gauge No. 6 - Parallel Modified Thread Form Check Ring Gauge
Suggestion on Which Gages to Use
If the requirement for using gages is internal to your company; use either standard. If the requirement for using gages is enforced by your customer; use the specification which they identify.
This data is provided for general information only. The intention
is to provide accurate information; regardless; errors may exist
in the supplied information. If accuracy is critical, base your
final decisions on the data provided in the root documents: BS-21:1985; ISO 7-2:2000; and EN 10226-3:2005; which are a copyrighted documents. To purchase a copy visit
an Authorized Reseller.
Original Posting: 1/2/2008
Last Revision: 1/28/2015
If you have some old documentation which will make this history more complete and you are willing to share; please email the document(s) to me at: email@example.com.