Losmandy OPW-11 One-Piece Worm Block — No Worm

Product Overview

The OPW-11 is a Losmandy one-piece worm block supplied without the worm, for an owner who already has a high-precision brass worm. It is a precision bearing block in a 7075 aluminium housing, built around an all in-line motor and gearbox worm design, with preloaded bearings and screw-adjusted worm gear mesh.

Who It's For

This is the block to order when the worm in your axis is still good and the block around it is not — or when you are converting an older two-piece bearing-block axis to the one-piece housing. If you need a worm as well, the version supplied with one is the part to look at instead.

Key Features & Design

• One-piece precision bearing block in a 7075 aluminium housing.
• All in-line motor and gearbox worm design.
• Preloaded bearings.
• Screw-adjusted worm gear mesh.
• Worm not included — for use with a high-precision brass worm you already own.

Mechanical Design

Losmandy identifies two sources of backlash in an axis: the mesh of worm against gear, and play in the worm between its own bearings. On the older arrangement, mesh was set by loosening the screw behind the outer bearing block, pivoting the worm into the gear by hand, re-tightening, then checking the worm still turned freely. The one-piece block makes that a screw adjustment instead, with the block itself holding the worm's alignment.

Preloaded bearings deal with the second source. Rather than shimming out play, the bearings are preloaded from the start, so the mesh you set stays where you set it.

Recommended Uses

Replacing a worn or damaged worm block while keeping an existing worm. Converting an older axis to the one-piece block design. Keeping a spare block for a mount in regular use. Rebuilding an axis with a new high-precision brass worm if the original is also worn.

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.
• With a worm: the OPW-11/W is this block supplied complete with a worm.
• Worm alone: the high-precision brass worm is stocked separately.
• Older design: the worm bearing blocks, set of 2 serve a two-piece axis you are not converting.
• Motor coupling: the G11 and GM8 motor-to-worm couplings join motor to worm.

Good to Know Before You Order

• No worm in the box. This version exists for owners who already have one.
• Fit depends on your axis, not just the mount name. Send us the mount model and axis and we will check it.
• This is an internal mechanical part. Fitting it means opening the axis, with the mount manual alongside.
• 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 rather than an accessory fit. The motor and worm cover come off, the old block comes out, this one goes in, and the mesh is set with its adjustment screw.

Does it include the worm?

No. The OPW-11/W includes one.

Will it fit my mount?

Send us the mount model, the axis and whether the motors are tucked or non-tucked, and we will confirm which block you need.

How is this different from the OPW-8?

They are different blocks in the same range, for different axes. Rather than guess from the part number, tell us your mount and we will identify the right one.

What does the one-piece design change?

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

Bottom Line

In short: a one-piece precision worm block in a 7075 aluminium housing, preloaded bearings, screw-adjusted mesh, supplied without a worm — for rebuilding an axis when the worm you have is still good.