How to set the belt Tension on a Thunder Laser Bolt Series Laser Machine

Preface: this article covers how the tensioner and belt clamp works on the X axis for a Bolt Laser machine. The belts on these axes are tooth cogged belts (timing belts) and do not require a great deal of tension.

Tools Needed

1. 7mm Crescent wrench
2. 2.5mm Allen Wrench
3. 2mm Allen Wrench

Identify Locations, Parts Descriptions and Tool Sizes

Tensioner	Laser Head
1. Jack Bolt Lock Nut (7mm) 2. Jack Bolt (2mm) 3. Tensioner Lock Bolts (2.5mm) The X axis tensioner is located on the left side of the machine on the gantry bar and moves front to back with the gantry	1. Belt 2. Belt Clamp Block 3. Belt Clamp Block Bolts (2.5mm)

Basic Belt Tensioning Process

Power off the machine and unplug from power prior to beginning this work.

1. Loosen up tensioner to allow additional slack in belt

To loosen up the tensioner we need to do the following steps:

With the 7mm wrench, loosen the Jack Bolt Lock nuts a few turns (Do not remove):

With the 2mm wrench, loosen the Jack Bolts a few turns until flush with the Tension bracket (Do not remove):

With the 2.5mm wrench, loosen the Tensioner Lock Bolts a few turns (Do not remove):

Slide the tensioner to the gantry bar, this will allow the maximum amount of slack to be pulled out in the next step and allow for the most adjustment range when adding tension back to the belt.

2. Remove Bulk of Belt slack with Belt Clamp on Head

Move the Laser head to the center of the Gantry and then......

Loosen the 2 Belt Clamp Block Bolts a few turns (Do not remove):

Pull out the slack of the belt through the block, tighten the Belt Clamp Lock Bolts:

3. Tension belt with Tensioner

Once the bulk of the belt slack is removed, use the tensioner to tighten the belt back up to adequate tension.

Tighten the Jack Bolts (Clockwise) evenly to tension the belt:

Even Adjustment	Uneven Adjustment (Avoid)

Tighten the Tensioner Lock Bolts:

Then with the 7mm wrench and 2mm Allen wrench, tighten the Jack Bolt Lock Nuts:

4. Reset the machine to allow it to home

Power the machine back up and let it home the axes.

Jog the X axis back and forth, listening for noise and observing the belt motion. If the belt looks loose or too tight, adjust the tension again if needed.

Good Even Tension Example:

Left Side	Right Side