REFERENCE / PARTS
Drill sizes for Eurorack panel parts
A Thonkiconn jack needs a 6 mm hole, a 1/4 in jack 9.53 or 10 mm, a 4 mm banana socket 8 or 8.33 mm, an Alpha 9 mm pot and a Bourns PEC11R encoder 7 mm, a Dailywell sub-mini toggle 5 mm, a mini toggle 6.35 mm, and LEDs 3 or 5 mm.
Panel holes
| PART | TYPE | HOLE Ø (MM) | HARDWARE Ø (MM) | DATASHEET |
|---|---|---|---|---|
| Thonkiconn jack | 3.5 mm jack | 6.00 | 7.80 | QingPu PJ398SM / WQP518MA |
| Switchcraft 1/4 in jack | 6.35 mm (1/4 in) jack | 9.53 | 15.87 | Switchcraft 112A / 11 / 12A |
| Rean 1/4 in jack | 6.35 mm (1/4 in) jack | 10.00 | 15.00 | Rean NYS229 / NYS230 |
| Johnson banana socket | 4 mm banana socket | 8.33 | 11.13 | Johnson (Cinch) 108-0902-001 |
| Tayda banana socket | 4 mm banana socket | 8.00 | 10.80 | Tayda J072 / Hirschmann BIL 20 |
| Alpha 9 mm potentiometer | Potentiometer | 7.00 | 12.00 | Alpha RD901F-40 |
| Bourns PEC11R encoder | Rotary encoder | 7.00 | 12.00 | Bourns PEC11R |
| Dailywell sub-mini toggle | Toggle switch | 5.00 | 8.00 | Dailywell 2MS |
| Dailywell mini toggle | Toggle switch | 6.35 | 10.80 | Dailywell 1MS |
| LED, 3 mm | LED | 3.00 | — | T-1 body |
| LED, 5 mm | LED | 5.00 | — | T-1¾ body |
Drill the hole named above and open it up slightly if the part needs play; going under it means the bushing will not pass. On a 3D printed panel, print a test piece first: holes usually come out a little under their nominal size.
Knob diameters
The hole is only half of the spacing problem. A knob has to clear its neighbours, and the skirt is wider than the shaft.
| KNOB | WIDEST Ø (MM) |
|---|---|
| Thonk Tall Trimmer Topper | 7.80 |
| Davies 1900H clone (Tayda) | 12.70 |
| Rogan PT-1PS | 14.38 |
| Rogan PT-2PS | 15.75 |
| Rogan PT-3PS | 18.47 |
Two Davies 1900H knobs need at least 12.70 mm between centres to touch, and more to be comfortable. The editor outlines every knob, nut and washer on the canvas and turns the outline red where two of them overlap.
Questions
What size hole does a Thonkiconn jack need?
6 mm. The bushing of the QingPu PJ398SM is 6 mm across, and its knurled nut covers 7.8 mm on the front of the panel.
What size hole does a 1/4 inch jack need?
9.53 mm (3/8 in) for Switchcraft jacks, whose 3/8-32 bushing takes a nut and a 15.87 mm washer on the front, and 10 mm for Rean NYS229 and NYS230 jacks. 10 mm is also the hole Kosmo builders drill for their 1/4 in jacks.
What size hole does a 4 mm banana socket need?
8.33 mm for Johnson (Cinch) sockets, sold for Buchla and Serge builds, and 8 mm for Tayda J072 and Hirschmann BIL 20 sockets. Their insulated head covers 11.13 and 10.80 mm on the front of the panel.
What hole do Alpha 9 mm potentiometers need?
7 mm, for the M7 × 0.75 bushing. The nut and washer cover 12 mm on the front, so two pots need at least that much space between centres before their knobs are considered.
Sources
Thonkiconn from the QingPu PJ398SM and WQP518MA datasheets; the 1/4 in jacks from the Switchcraft catalog and the Rean NYS229 drawing; the banana sockets from the Johnson 108-0902-001, Tayda J072 and Hirschmann BIL 20 drawings; Alpha 9 mm from the RD901F-40 datasheet; the encoder from the Bourns PEC11R datasheet; the toggles from the Dailywell 1MS and 2MS datasheets. The editor applies them in parts.ts.
Draw it instead of measuring it
Eurorack Panel Designer applies every number on this page automatically: pick a width in HP or millimeters, drop the parts, and export an STL, an SVG, a PNG or a KiCad Edge.Cuts outline. It runs in the browser, it is free, and it needs no account.
Open the editor