Top Clamp with Height-Adjustable Riser

A versatile Makera-style top clamp with an integrated height-adjustable riser, designed to make clamping different material thicknesses easier while maintaining the proper clamp angle and pressure.

The design is based on the familiar Makera top clamp, including the front lip that sits on the edge of the material, but adds a simple threaded adjustment at the rear of the clamp.

Instead of placing a separate spacer or riser block underneath the back of the clamp, an M5 flat-head screw installed in reverse acts as an adjustable rear support. Turning the screw in or out raises or lowers the heel of the clamp, allowing you to fine-tune the clamp angle for the thickness of material being held.

Why an Adjustable Riser?

The adjustable riser does more than simply compensate for thicker material. It allows the clamp to sit at the proper working angle so the front lip can apply pressure in two useful directions.

When adjusted correctly, the clamp provides:

Axial / downward pressure to push the material firmly against the CNC bed.
Lateral / sideways pressure from the front lip to help hold the material against its locating edge or fixture.

This combination helps keep the stock both seated against the bed and restrained from shifting sideways during machining.

The clamp should normally sit close to parallel with the top of the material, with the rear riser end slightly lower when appropriate. This slight angle allows the front lip to engage the side of the stock while still maintaining strong downward clamping force.

If the rear of the clamp is positioned too high or too low, the clamp can sit at an ineffective angle and reduce how well the lip contacts the material. The adjustable M5 riser allows the clamp geometry to be fine-tuned for the stock being used.

Integrated M5 Adjustable Riser

The adjustment mechanism is intentionally simple.

A standard M5 flat-head screw is installed in reverse through the threaded hole at the rear of the clamp. The broad, flat face of the screw head rests against the CNC bed and acts as the adjustable foot.

Turning the screw changes the rear height of the clamp, making it easy to accommodate different stock thicknesses without keeping multiple fixed-height riser blocks nearby.

Once adjusted, the riser helps keep the clamp in the proper position so the lip can maintain a useful balance of downward and lateral holding pressure.

Use It as a Standard Makera-Style Clamp

The adjustable riser is completely optional.

Simply remove the M5 adjustment screw and the clamp can be used like a traditional Makera-style top clamp.

This gives you both options in a single design:

Use the M5 screw when an adjustable rear support is helpful.
Remove the screw when you want to use the clamp in the standard Makera-style configuration.

Two Clamp Sizes Included

The project includes both full-size and compact half-size clamps.

Full-Size Clamp

The full-size version is approximately the same overall length as the standard Makera top clamp and works well as a general-purpose clamp for larger stock and normal workholding setups.

Half-Size / Compact Clamp

The half-size version takes up considerably less bed space while retaining the same basic clamping function.

It is especially useful on the smaller Makera Z1 bed, where conserving usable work area can make a big difference. The compact size is also useful for smaller workpieces, tighter fixture layouts, and setups where several clamps need to fit around the stock.

Project Files Included

The supplied project files are set up to produce a complete 5-clamp set:

3 × Half-Size / Compact Clamps
2 × Full-Size Clamps

Both sizes include the height-adjustable riser feature and can also be used as standard Makera-style clamps by simply removing the M5 adjustment screw.

🧩 Hardware Required per clamp

M5 × 20-25mm Flat Head Socket Screw

Features

Makera-style top clamp design
Integrated height-adjustable rear riser
Uses a standard M5 flat-head screw
Reverse-mounted screw provides a broad, flat contact surface against the CNC bed
Adjustable for different material thicknesses
Helps maintain the proper clamp working angle
Provides strong axial / downward pressure & lateral / sideways restraint
Helps eliminate the need for separate riser blocks
Can be used as a standard Makera-style clamp by removing the adjustment screw
Includes both full-size and compact half-size versions

Basic Adjustment

Position the clamp so the front lip sits properly on the edge of the material.
Adjust the rear M5 screw in or out to raise or lower the heel of the clamp.
Set the clamp close to parallel with the top of the stock, with the rear riser end slightly lower when appropriate.
Tighten the main clamp screw normally.
Confirm that the material is firmly seated against the bed and cannot move sideways before beginning machining.

The M5 screw acts only as the adjustable rear support. The primary clamping force is still provided by the normal Makera bed-clamping hardware.

A Simple Upgrade to a Useful Clamp

The goal of this project is to keep the simplicity and convenience of the original Makera-style top clamp while making it more adaptable to different material thicknesses.

The adjustable riser lets you fine-tune the clamp angle so the front lip can maintain the proper combination of downward and lateral pressure, rather than relying on a collection of fixed-height spacer blocks.

When the adjustment is not needed, simply remove the M5 screw and use the clamp like a standard Makera-style top clamp.

The included files produce a practical set of three compact clamps and two full-size clamps, giving you several options for different workholding setups and machine bed sizes.

🔧 Machining the Adjustable Top Clamps

Tools Used:
- 3.175 × 12 mm For Metal
- M5 (d4) x 15 mm Thread Milling Bit

Material Used:
The set of adjustable top clamps can be machined from a single ~100×100×5mm aluminum plate using the following setup.

🎥 Video - Making The Top Clamps

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