Front Idler
This guide covers replacing the front idler bearings on the Vision Miner 22IDEX V4. The machine has four front idlers – one per belt (two for the Y-axis, two for the toolhead belts). Over time, idlers can wear out, develop flat spots, or start making noise, causing belt vibration and print quality issues.
Before you begin - safety and risk
Read the Safety - Before You Begin article to understand the hazards involved in working on the Vision Miner 22IDEX V4 - including electrical, thermal, mechanical, and chemical risks. All procedures in this wiki are provided as recommendations only. By choosing to follow any procedure, you do so at your own risk.
Tools and Materials
- 2.5 mm Hex screwdriver (hex wrench) – for belt clamp plate screws
- 3 mm Hex screwdriver (hex wrench) – for idler screws
- Replacement idler bearings
- Threadlocker (we recommend Loctite 243)
- Guitar tuning app on your phone (for verifying belt tension at 65 Hz after reassembly)
- Small container or magnetic tray (to hold washers and screws)
Releasing Belt Tension
- Locate the belt tensioning knob on the front of the machine for the idler you are replacing.
- Unscrew the tensioning knob by hand, turning it counter-clockwise. Remove it completely.
- Catch the washer behind the knob – it will fall off as you remove the knob. Set the knob, spring, and washer aside.
Freeing the Belt
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Release the belt from its clamp so it is no longer looped around the idler:
- Y-axis belt: Slide the belt out from under its clamp.
- Tool belt (Tool 0 / Tool 1): Loosen the four screws on the belt clamp plate at the back of the toolhead and pull the belt free.
For detailed clamp plate instructions, see the Belt Replacement Guide.
Securing the Tensioner
- Place the washer back onto the tensioning knob shaft.
- Screw the tensioning knob back in clockwise, almost all the way in. This holds the idler assembly firmly in place so you can unscrew the idler bolt without the assembly moving.
Removing the Idler
- Insert the 3 mm hex screwdriver into the idler screw. Push it all the way in and keep it straight – the screw has threadlocker and will resist. The idler screws are installed with threadlocker and will be stiff to remove – insert the hex screwdriver fully and keep it straight to avoid stripping the screw head.
- Unscrew and remove the screw. It is stainless steel with threadlocker applied – expect firm resistance.
- Pull the idler out. Note the two small M5 washers – one on each side of the idler, acting as spacers. Do not lose them. If the screw feels like it won't budge, do not tilt or wobble the hex screwdriver – re-seat it fully and apply steady force. Stripping the hex head makes removal much harder.
Installing the New Idler
- Place one M5 washer on one side of the new idler bearing.
- Position the idler in the mounting slot with the washer in place. Add the second M5 washer on the other side.
- Apply a small amount of threadlocker to the screw threads.
- Insert the screw through the washers and idler. Tighten firmly with the 3 mm hex screwdriver.
- Spin the idler by hand. It should rotate freely with no grinding or resistance.
Reassembly
- Turn the tensioning knob counter-clockwise to release the tensioner so the belt can be routed around the new idler.
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Route the belt back around the new idler and re-clamp it:
- Y-axis belt: Slide the belt back under its clamp. Make sure it sits flat – not twisted or bunched.
- Tool belt (Tool 0 / Tool 1): Feed the belt ends back into the clamp plate and tighten the four screws in a cross pattern.
For detailed clamp plate instructions, see the Belt Replacement Guide.
Setting Belt Tension
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Set the belt tension to 65 Hz using a guitar tuning app. For the full tensioning procedure, see the Belt Tensioning Guide. The spring inside the tensioner must not be fully compressed – the knob should sit roughly flush with the tensioner screw, leaving room for the spring to absorb slack over time.
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If replacing multiple idlers, repeat the entire procedure (steps 1–17) for each one.
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Slide the gantry and toolheads manually across their full range of travel. Movement should be smooth with no binding or unusual noise.
FAQ
Troubleshooting
Support
If you could not find an answer here, reach out to our support team.