Multitool digital thickness gauge

I redesigned the front part of a cheap chinese thickness gauge to be able to attach different tools, like ones for belt tension check. The tools are uploaded as separate models.

Bill of materials

• cheap chinese plastic digital thickness gauge (buy_link_1 buy_link_2 etc.)
• 2 M3x5 screws
• 4 m3 square nuts
• 4 M3x20 screws
• PLA

Disassembly

Please read all the instructions before proceding.

1. remove the back cover (it is press fitted)
    
   
2. remove the lever and the pin (after releasing the spring)
   
3. unscrew the 4 tiny screws (Philips 00), remove the final black part and put aside the spring (in the picture the spring is above the the right screw). The final black part will be replaced with a new printed one.
   

Printing and installing the new front multitool dock

Open the 3mf file in PrusaSlicer and print it with PLA. No supports needed.

Installing steps:

1. cut the back of the pin (for larger distances), install the multitool dock and tighten the 4 screws
   
2. attach the spring to the cover
   
3. put the black pin and the cover. Fix the cover with 2 M3x5 screws
4. attach the spring to the pin
   
5. press the lever into position
   
6. press the back cover into position
   

Designing tools

Tool design is simple. A tool needs to have two 3mm holes, separated by a 10mm center distance (6mm on X axis, 8mm an Y axis). Here is the picture:

Installing a tool

Use M3 screws and m3 square nuts:

Belt tension tools

Expert (with ball bearings)

Expert belt tension checking tool (printables model here) 

Advanced (no ball bearings)

Advanced belt tension checking tool (printables model here)