Fully parametric ergonomic hex bit handle for ¼" (6.35mm) shank bits. It is designed to be compact and provide maximum amount of grip.

This model uses a magnet (D4x2 mm by default, can minimally configured), but it is not necessary to function (the bit with correct clearance does not fall out).

The magnet is press-fitted into the bottom of the hole. To install it, first attach a magnet to the bottom of the largest drill bit, making sure it is cantered. Then carefully press the magnet into the hole. If a magnet does not press-fit securely, add a small drop of super glue to the bottom of the magnet before inserting it into the slot.

Every parameter is configurable:

• hex bit diameter clearance (default is set to 0.35mm, for 0.4mm nozzle and 0.20mm layer height; the diameter is set to nominal 6.35mm)*
• handle diameter (diameter of the handle; minimum possible diameter is 25mm)
• “grip factor” (provides deeper or shallower grooves; insert factor from 0.2 for minimum groove to 0.5 for maximum groove; default: 0.4; see below)
• hex bit socket depth (the depth of the socket – how deep is socket seated in the handle; default is set to 12mm; possible values are from 8mm to 25mm; make sure the bit is not fully submerged)
• handle grip height (this is the height of the grip; default and minimum value: 12mm; total height is this value plus “bit collar height” + 1mm base)
• bit collar height (height of the “collar” part; default and minimum value: 5mm)
• magnet diameter (insert nominal diameter value; possible values from 4mm to 5mm; default: 4mm)
• magnet diameter clearance (clearance for the magnet diameter; default – for 0.4mm nozzle and 0.20mm layer height – is set to 0.35mm)
• magnet height (insert nominal magnet height; the 0.1mm clearance is added automatically)
• handle grip inset distance (distance from the outer diameter to the deepest point of the inset; set to 0mm for a straight handle; max.: 2mm; default: 1mm)

*Please note that, according to the ISO standard, ¼ inch hex bit shanks can range from 6.35 mm to 6.29 mm across flats. I used Wera bits measuring around 6.30 mm, so you may need to adjust the clearance depending on your bits and printer calibration.

“Strength” print profile (6 walls, 25% infill) recommended.

“Grip factor” demonstration:

Grip factor at 0.2 (see picture above).

Grip factor at 0.5 (see picture above).