MM 4040 Two-Arm Keyboard Swivel Kit

Installation and use guide

A simple guide to attaching the finished mounts and arms to your rig, fitting your tray and using the swivels.

Download installation guide (PDF)

The swivel assemblies are supplied factory complete. Customer installation uses the finished mounts and arms.

Bring the keyboard to you. Swing it away when you're done.

The MM 4040 Two-Arm Keyboard Swivel Kit adds a repositionable arm to a compatible vertical 4040 post. One swivel joins the post to the first horizontal arm. The second swivel joins the two horizontal arms, so you can fold and extend the arrangement to bring your keyboard tray toward your seat or move it out of the way.

Intricate machined components give this compact kit its premium construction. Both swivel assemblies arrive factory complete. Attach the finished mounts and arms to your compatible rig, then fit your chosen keyboard tray.

The kit uses two 10-inch extrusion arms and a compact joint design built around the 40 mm profile size. It is intended for a separate keyboard tray and a secure supporting frame. A keyboard, tray and vertical post are not included.

Two swivels. More ways to position your tray.

Post-to-arm movement

The first joint mounts at the side of a compatible vertical post and lets the first horizontal arm rotate around a vertical pivot. Place the post attachment at the height your installation requires, then plan the tray position around your seating and wheel clearance.

Arm-to-arm movement

The elbow joins the two horizontal arms at the same height. Moving both joints gives you more positioning choices than a single straight arm, while keeping the arrangement based on familiar 4040 extrusion.

A compact joint arrangement

The current design keeps the finished joint bodies within the 40 × 40 mm profile envelope. Leave clearance around the joints, mounting fasteners and cables throughout the movement.

Fit and movement

• Configuration: One post-to-arm swivel and one arm-to-arm swivel
• Included extrusion: Two 10-inch (254 mm) pieces of 4040 extrusion
• Total extrusion length: 20 inches (508 mm)
• Arm orientation: Two horizontal arms with vertical swivel axes
• Joint body envelope: 40 × 40 mm in the current CAD design
• Installation: Attach the finished mounts and arms to a compatible rig and tray
• Adjustment: Free swivel, without angular locking
• Installed reach: Depends on both joint angles, mounting position and tray attachment
• Load capacity: A tested working load rating has not been published. Confirm your intended keyboard and tray with us before ordering.

What is included?

• One factory-complete post-to-arm swivel assembly
• One factory-complete arm-to-arm swivel assembly
• Two 10-inch pieces of 4040 extrusion

Sold separately: Keyboard, keyboard tray, tray attachment hardware, vertical supporting post and cockpit or stand. Profile-specific installation fasteners must be confirmed for your exact post. This kit does not include a locking mechanism.

Check your extrusion before ordering

The design is based on 40 × 40 mm extrusion with compatible 8 mm mounting slots. Profiles with the same outside dimensions can have different mounting slots. Send us the manufacturer and profile number, or a clear photo, so we can check the mounting arrangement.

The included arms are the kit's matching extrusion. The attachment to your own post and the connection to your chosen tray still need to be compatible.

Installation, movement and care

Read the installation guide, secure the supporting frame, and confirm mounting height before attaching the finished kit. Check that the mounting fasteners are secure. Fit the tray using hardware intended for that tray and profile, then check the full movement with the assembly supported.

Route cables with enough slack for both swivels and keep them out of the joint gaps. Move the arm by hand and check clearance around the wheel, seat and cockpit. Inspect for loose fasteners, excessive play or damage during use. Because the joints do not lock, avoid installations where unintended movement could cause a collision.

Frequently asked questions

Do I have to assemble the swivels themselves?

No. Both swivels are supplied factory complete. You attach the finished mounts and arms to your compatible rig and fit your keyboard tray.

Is each extrusion arm 20 inches long?

No. The kit has two 10-inch arms. Together, they contain 20 inches of extrusion. Joint spacing and the selected angles determine the final reach.

Does the arm lock in place?

No. Both joints are free swivels. Choose this kit when you want to move the tray by hand without releasing an index pin or angular lock.

Does it come with a keyboard tray?

No. The $99 presale kit includes the extrusion arms and swivel mounts. You supply the tray, keyboard, upright and compatible tray attachment hardware.

Can I mount it to any 4040 post?

Profile geometry varies. The current design uses compatible 8 mm slot geometry, so please confirm your post with us before ordering.

How much weight can it hold?

A tested working load rating is not yet published. Send us the combined keyboard and tray weight, the tray dimensions and your intended position so we can review the application.

When will my preorder ship?

Orders start shipping November 1, 2026. This is the beginning of shipping, with carrier transit time additional. Shipping is charged separately.

Your keyboard arm package

Make it fit your setup

Send your extrusion profile, keyboard and tray details, and a photo of the mounting area to mitchell@mmsimracing.com, or contact Mitchell. Review the store's shipping policy and return and refund policy for applicable terms.