In this instructable, I will show you how to repair planetary gear of Li-ion screwdriver model IXO manufactured by Bosch. My search at WWW found only repair instructions on how to change the battery. This was not my case.
The problem of my screwdriver was lack of exit force. The motor was audible, but there is no chuck rotation. After an easy disassembly procedure, I found that second planetary gear tooths are destroyed.
I will describe step by step the process as tightly as possible with lots of pictures.
Step 1: Step 1: Tools and Fabrication Techniques
1. 1-hour free time :)
2. Appropriate screwdriver, only size matters.
3. Sandpaper (hard P80 and soft P800).
4. Acrylic/Plexiglass 4 mm thickness (PMMA)
5. Access to a laser cutter or local dealer of this kind of service (I used service).
6. Tweezers with the appropriate size for small details.
7. Pliers small ones.
8. Glue (a few drops of fast drying glue).
9. High-speed grease. Gears should be well lubricated.
Step 2: Step 2: Laser Cut Part Files
I will spare you unsuccessful experiments to build the gear by handy 3D Pen or moulding clay. :)
Laser cutting machines are very precise as I learned trying to make gear as thin as possible, so it can fit in the chuck. Measurements are visible in the first picture. The main problem was to make a gear that has the exact number of teeth and a very thin wall to hold them. The PLT file format is usable on many laser cutting software directly. The SVG file format is the original source and commonly editable.
There is a square figure in both files with exact dimensions - 10 x 10 millimetres. It is used for a calibration checkup. The first cut should be the square. If it is not exactly 10 x 10 millimetres then a change in a global parameter for cutting software or loaded file is needed.
Cut few gears, they are fragile and could be broken at the fitting process.
Step 3: Step 3: Dissasembly
The disassembly process is very easy just follow the step by step pictures.
2. Open the plastic cover.
3. Remove the chuck.
4. Open the chuck. Be very careful there are small parts.
Step 4: Step 4: Fitting the Planetary Gear Ring
1. Remove the grease and clean chuck inside.
2. Sand the damaged teeth with sandpaper by hand.
3. Sand gently by hand the bed for new gear ring. For referral border, I assumed the line marked with red colour.
4. Regularly check if sanding is enough and gear ring fits tight.
5. Position the new gear ring aligned in line with remaining undamaged old teeth
6. Use a few drops of glue to fasten the gear ring. Wait appropriate time.
Step 5: Step 5: Assembly
The assembly process is very easy just follow the step by step pictures.
1. Put enough grease at every moving or stationary chuck parts.
2. After closing the chuck remove any overflow grease.
Remember grease reduces friction.
Congratulations a screwdriver is alive. ;)