Precision Screwdriver with Bit Storage (4mm bits)

Overview

This precision screwdriver is designed to fit standard 4mm bits. A bit holder is located inside the handle, allowing you to neatly store 6 additional bits. The handle is 20mm in diameter and has a rotating end cap.

Please note that since the bit interface is plastic, this screwdriver is best suited for precision and light-duty use, such as fixing electronics. It will likely not withstand excess torque.

The standard version needs just one extra part: a 4mm diameter, 2mm depth magnet. There are alternative versions available if you want a bigger magnet, no end cap or for a 625 bearing in the end cap.

I would definitely recommend the version with the 625 bearing, as this is much smoother and durable.

Parts

There are three parts: The handle, bit holder and end cap.

The handle has two variants;

• Standard - Has a recess for a 4mm diameter x 2mm depth magnet.

• Deeper Magnet - If you want a stronger magnet, you can print this version, which will allow you to use a magnet up to 4mm diameter x 8mm depth.
  

The bit holder screws into the handle, and has 6x clips to hold the extra bits. It has three variants:

• Standard - This version has a hole in the bottom to allow the standard end cap to clip in.

• No End Cap - Print this version if you don't want the spinning end cap.

• 625 Bearing - This version accepts a 625 bearing for a smoother and more durable end cap.
  

The end cap has two variants which must be paired with the relevant bit holder:

• Standard - This version clips into the bit holder.

• 625 Bearing - This version accepts a 625 bearing for a smoother and more durable end cap.

Printing

This model has a lot of small/intricate details which need to be both accurate and strong. You need to have a good layer adhesion.

• Material - I recommend using ASA/ABS, or another strong material that you have a good printing profile for.

• 0.4 mm nozzle (or smaller)

• 0.15 mm layer height - (or smaller) This is important for the threaded parts to print properly.

• No support material required, except for the 625 bearing variant of the bit holder, which needs them under the bearing recess.

• 70-100% Infill, 3 wall perimeter thickness - This is recommended to ensure the highest possible strength. I recommend using 100% infill on the bit holder to maximise the layer surface area.

• Brim recommended if you aren't super confident in your bed adhesion.

• Material shrinkage/tolerances - The parts are designed with the shrinkage of ASA and ABS in mind, and tested on my printer. You may need to scale them by a small amount for your printer, and also if you use a different material.

Assembly

The assembly should be fairly simple, but I have a few notes:

• Because of the tight tolerances, the bit may be a tight fit into the handle at first. I found that after pushing it in firmly a few times the fit became good.

• Be careful when clipping the end cap into the bit holder, as this is when the clips are most likely to break.

• To install the magnet, I stuck it to the end of a bit, then pushed it into the hole firmly. I used a small amount of glue to ensure it doesn't fall out.