Screw taps for RMS microscope thread according to DIN 58888

RMS – Microscope Thread

The RMS thread is a screw thread with a very specific application. In addition to microscopy, it was also used in macro photography, but otherwise it is rarely found. The microscope thread was designed as early as the mid-19th century by the Royal Microscopical Society in Great Britain and has since been used unchanged as the standard thread for microscope objectives. Even though the use of the RMS thread is limited to a very narrow field, you will, as always, find all the necessary tools in our online shop.

Everything you need to know about the Royal Microscopical Society objective thread according to DIN 58888

The RMS thread table contains only a single thread size. The history of the microscope objective thread begins in Great Britain, where at the time of its creation it was based on one of the already common thread standards. At that time, the most widespread was the well-known Whitworth thread of the British engineer Joseph Whitworth, who is widely regarded as the father of standardized screw threads. The dimensions of the RMS thread are therefore based on this Whitworth thread.

Accordingly, the Royal Microscopical Society microscope objective thread has a flank angle of 55°. The nominal diameter is 0.8 inches, with a pitch of 1/36 inch. Converted into metric values, this corresponds to approximately 20.32 mm × 0.71 mm. The thread designation is W 0.8" × 1/36". Despite the letter W, the RMS thread is not simply a variant of the BSW thread, but has its own standard according to DIN 58888 and ISO 8038. Tools are therefore not interchangeable without restrictions.

While the RMS thread is no longer used in photography, it remains the standard for microscope objective threads, unless other thread connections are required for optical or design reasons. This ensures that microscope objectives remain flexible and easy to interchange.

RMS Thread – Our Range

If you work with microscopes or are involved professionally or as a hobby with old camera models, you may occasionally need to produce or repair an RMS thread. In such cases, BAER is your reliable partner to equip you with the necessary tools. In our well-stocked online shop you will find everything you need.

RMS Tap W 0.8" × 1/36"

Our RMS tap is a single-cut tap. This means you can create the desired thread either by hand or with machine assistance in just one operation. The RMS tap is manufactured from high-quality HSSG, ensuring precise results and long durability. The Form C design with straight flutes is suitable for both through and blind holes.

RMS Die W 0.8" × 1/36"

If you want to cut an external RMS thread, our round die is the right tool. Whether used manually with a die holder or in a machine – the BAER die for the RMS thread always ensures optimal results.

Discover tools for the RMS microscope thread in our online shop!

At BAER we not only offer taps and dies for the RMS thread in excellent quality, but also many other tools and accessories, along with first-class customer service. From a straightforward ordering process and fast shipping to always having an open ear for your questions and concerns. Just give us a try! Our friendly staff are available at any time by phone or conveniently via our contact form.