How to lay out thirty bits
A set of this size is usually three families, and three rows suit that: cross-head bits in the front row, star-shaped bits in the middle, hex and slotted at the back. Ten pockets per row keep the block at 99 mm, the same length as the ten-bit and twenty-bit holders on this site, so the three line up on a shelf. If your set is mostly 50 mm power bits, put those in the back row; they stand 38 mm clear of the block and would hide short bits behind them.
What to measure
Count the bits you own first and round up, not down: an empty pocket costs nothing and a missing one means a loose bit. Then measure a few shanks across the flats. Bits from different makers differ by a few hundredths, and thirty pockets will meet the widest one you have. If any bit measures over 6.4 mm, raise the clearance to 0.3 mm for the whole block.
Clearance, wall and material
The pockets are 6.6 mm across flats, from 6.35 plus 0.25 mm of clearance, with 3 mm of solid material between pockets and around the edge. The block is 14 mm high on a 2 mm floor, giving pockets 12 mm deep. With three rows, the gap between rows matters more than the gap along a row, because fingers reach in from the front: if the middle row is hard to grip, raise the wall between pockets to 4 mm, which adds 9 mm to the length and 2 mm to the depth.
Printing
Print flat with the pockets up and no supports. This is the largest bit holder on the site, with a footprint near 99 by 35 mm, and a solid block of that size can lift at the corners in PLA on a cool bed. Use 15 percent infill instead of more: less plastic means less shrinkage, and the pockets get their strength from their own perimeters. Thirty pockets mean thirty seams, so set the seam to the rear or to random to keep blobs out of the hexagons.
Outline drawing
Top view, to scale. Pocket centres are 9.6 mm apart along a row and about 10.6 mm apart between the rows.
Parameters the generator will use
| Setting | Link parameter | Value |
|---|---|---|
| Model | model | bit_holder |
| Bits per row | count | 10 |
| Rows | rows | 3 |
| Bit size across flats | across_flats | 6.35 |
| Pocket clearance | clearance | 0.25 |
| Wall between pockets | gap | 3 |
| Wall around the pockets | margin | 3 |
| Strip height | height | 14 |
| Floor under the pockets | floor | 2 |
All lengths are in millimetres. Outer size from these values: about 99 x 34.86 x 14 mm.
Open the generator with these values
This model needs the $7 licence key: one payment, one key, and it opens all five paid models. Get a licence key on Gumroad ($7)
The hex bit holder strip needs a licence key: without one the generator shows the model locked, lists the values from this link and fills them in as soon as you unlock. The fitted drawer organiser bin is the free model and downloads with no key.