What to measure
Two things: the bits and the place the block will live. For the bits, measure across two opposite flats of the shank with a caliper; standard quarter inch bits read 6.35 mm. For the place, measure the drawer compartment, tool case or shelf edge that the block has to fit. This block is 99 mm long and 24.2 mm deep with the values on this page. If the space is shorter than 99 mm, use three rows of seven instead of two rows of ten: the generator shows the new length and depth before you download.
Why two rows change the settings
In a single row you can pinch each bit from the front and the back. In two rows the back row is reached over the front row, so the bits need to stand taller and steadier. This page therefore raises the block to 14 mm, which makes each pocket 12 mm deep above the 2 mm floor. A 25 mm bit shows 13 mm above the block. The wall between pockets stays at 3 mm in both directions; rows are spaced about 10.6 mm apart, centre to centre, because a hexagon is wider corner to corner than across its flats.
Clearance and material
Pocket clearance is 0.25 mm, for a pocket of 6.6 mm across flats: a free drop-in fit in PLA. With twenty pockets, a fit that is slightly too tight is twenty times as annoying, so print a three-pocket test first by setting the bits per row to 3 and the rows to 1, try your bits in it, and adjust the clearance in steps of 0.05 mm. For PETG start at 0.3 mm. PLA is the easier material here, as it gives sharper pocket corners and less stringing across the openings.
Printing
Print flat, pocket openings up, with no supports. Use a 0.2 mm layer height and three perimeters. Twenty pockets mean many travel moves across open holes: enable retraction and, if your slicer has it, avoid crossing perimeters, or fine strings will bridge the pockets and have to be cleared with a spare bit. Infill of 15 to 20 percent is enough. A block this size has enough weight to stay put on a bench; glue a strip of rubber underneath if you want it not to slide.
Outline drawing
Schematic, not to scale. Pocket centres are 9.6 mm apart along a row and about 10.6 mm between rows.
Parameters the generator will use
| Setting | Link parameter | Value |
|---|---|---|
| Model | model | bit_holder |
| Bits per row | count | 10 |
| Rows | rows | 2 |
| Bit size across flats | across_flats | 6.35 |
| Pocket clearance | clearance | 0.25 |
| Wall between pockets | gap | 3 |
| Wall around the pockets | margin | 3 |
| Block height | height | 14 |
| Floor under the pockets | floor | 2 |
All lengths are in millimetres. Outer size from these values: about 99 x 24.2 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.