Player One M42F-M42M 20mm Extender

Product Overview

The Player One M42F-M42M 20mm Extender is a machined aluminium spacer that adds 20 mm of length between M42 × 0.75 (T-thread) components. It carries M42 × 0.75 female threads on one end and M42 × 0.75 male threads on the other, so it threads in line without changing the thread standard. It is used to build up spacing in an M42 imaging train — typically to reach a required backfocus distance.

Who It's For

This is a good match if you are assembling an M42-threaded imaging train and need a known 20 mm step to reach the backfocus your camera, filter drawer, or corrector calls for.

Key Features & Design

• Fixed 20 mm spacing: adds a precise 20 mm of length in a single component.
• M42 × 0.75 threads: female one end, male the other — the common T-thread / M42 standard.
• Aluminium 6061-T6: machined aluminium body, light and rigid.
• Mechanical only: no optical elements and no electronic connection.

Recommended Uses

• Backfocus spacing: add 20 mm toward a corrector, flattener, or camera backfocus figure.
• M42 train building: insert a known step between M42-threaded parts.

Compatibility & Accessory Notes

Both ends use the M42 × 0.75 thread standard — female on one side, male on the other. It passes the M42 thread straight through and does not convert to another standard. Backfocus is a sum of every part in the train; if you are working out how much spacing you need, send us your camera, filter, and corrector setup and we will work it out with you.

Good to Know Before You Order

• Mechanical adapter only: it adds length and carries the thread — there are no optics and no electronic communication through it.
• Fixed length: the 20 mm step is not adjustable.
• Thread standard: both ends are M42 × 0.75; it does not convert M42 to any other thread.

Frequently Asked Questions

Is it difficult to set up?

No — it threads directly in line between two M42 components and needs no tools or adjustment.

How much length does it add?

20 mm.

Does it change the thread size?

No. Both ends are M42 × 0.75, so it keeps the M42 (T-thread) standard on both sides.

Does it have any optics?

No. It is a mechanical spacer with no optical elements and no electronic connection.

Bottom Line

In short: a machined aluminium 20 mm spacer with M42 × 0.75 threads on both ends, made to set a known step of backfocus in an M42 imaging train.