Losmandy OPW-8/W One-Piece Worm Block with Worm

Product Overview

The OPW-8/W is a Losmandy one-piece worm block supplied complete with the worm. It uses precision bearing blocks in a 7075 aluminium housing, an all in-line motor and gearbox worm design, preloaded bearings and screw-adjusted worm gear mesh.

Who It's For

This is the complete assembly, and it is what most people want. A worn worm and a worn block usually arrive together — they wear against each other — so replacing both at once is what actually brings an axis back to specification. It is also the straightforward way to convert an older two-piece bearing-block axis to the one-piece design.

Key Features & Design

• Worm included.
• Precision bearing blocks in a 7075 aluminium housing.
• All in-line motor and gearbox worm design.
• Preloaded bearings.
• Screw-adjusted worm gear mesh.

Mechanical Design

Backlash in a Losmandy axis comes from two places: the mesh of worm against gear, and play in the worm between its own bearings. The one-piece block addresses both. Mesh is set by a screw rather than by loosening the outer bearing block and pivoting the worm into the gear by hand, which is how it was done on the older arrangement. The bearings are preloaded, so the worm has no free movement along or across its axis to begin with.

Supplying the worm with the block matters more than it sounds. Worm and gear wear as a pair, and a new worm bedding into a block whose bearings are already tired will not hold the mesh you set. Replacing the two together is the difference between a repair and a rebuild.

Recommended Uses

Rebuilding a worn RA or DEC axis to specification. Converting an older two-piece bearing-block axis to the one-piece design. Fixing persistent backlash that clutch and mesh adjustment no longer cures. Keeping a complete spare assembly for a mount in heavy or remote use.

Compatibility and Accessory Notes

• Which block fits your mount depends on the axis and its vintage. Tell us your mount model, which axis you are working on, and whether it has tucked or non-tucked motors, and we will confirm the correct block before you order.
• Without the worm: the OPW-8 is the same block for owners who already have a good worm.
• Worm alone: the high-precision brass worm is stocked separately.
• Motor coupling: the G11 and GM8 motor-to-worm couplings join motor to worm.
• Older design: the worm bearing blocks, set of 2 serve a two-piece axis you are not converting.

Good to Know Before You Order

• Fit depends on your axis, not just the mount name. Send us the mount model and axis and we will confirm the right block — worth a minute to save a return.
• This is an internal mechanical part. Fitting it means opening the axis. It is within reach of anyone comfortable with hand tools and the mount manual, and we will talk it through if you want.
• Replacing both worm and block is the point of this version. If your worm is in good order, the OPW-8 without a worm costs less.
• Losmandy publishes no weight or dimensions for this part.
• Specifications are Losmandy's published figures.

Frequently Asked Questions

Is it difficult to set up?

It is an internal repair. The motor and worm cover come off, the old assembly comes out, this goes in, and the mesh is set with its adjustment screw. Losmandy's mount manual covers the sequence.

Does it include the worm?

Yes — that is what the /W denotes.

Will it fit my mount?

Tell us the mount model, the axis and whether the motors are tucked or non-tucked, and we will confirm.

How do I know my worm block is worn?

Backlash that returns after you have set the mesh, or play you can feel in the worm itself between its bearings, are the usual signs. Describe what you are feeling and we will help you work out which part it is.

What does the one-piece design change?

Mesh becomes a screw adjustment rather than a matter of pivoting separate bearing blocks, and the preloaded bearings remove play in the worm.

Bottom Line

In short: a complete one-piece worm block with the worm included, 7075 aluminium housing, preloaded bearings and screw-adjusted mesh — the assembly that brings a worn axis back to specification.