Compiled by Ralph Barker for largeformatphotography.info
Having lensboards precision-bored with a machinist's lathe may be the next best
thing to buying lensboards pre-bored by the manufacturer. Metal boards (aluminum or mild sheet steel) can be easily
drilled with reasonable accuracy, however, with a good hole saw in a drill press. Similarly, a
good Forstner bit of the right size works well for wooden lensboards. Careful sanding or filing of the hole
may be necessary for a proper fit.
Forstner bits in sizes up to 2" are fairly common at better woodworking supply stores. Woodshed Tools, Inc. also carries sizes up to 3".
| Brand | # Size | Hole Size - mm | Hole Size - Inches | Nearest fractional size | Comments, lenses |
| Compur | #00 | 26.3mm | |||
| #0 | 34.6mm | 1.362" | 1 3/8" = 1.375" | ||
| #1 | 41.6mm | 1.638" | 1 5/8" = 1.625 | ||
| #2 | 52.5mm | oddball | |||
| #3 | 65mm | 2.559" | 2 1/2" | ||
| Copal | #0 | 34.6mm | 1.362" | 1 3/8" = 1.375" | |
| #1 | 41.6mm | 1.638" | 1 5/8" = 1.625 | ||
| #3 | 65mm | 2.559" | 2 1/2" | ||
| Ilex | #3 | 50.42mm | 1.985" | 1 7/8" = 1.875" | Kodak 10" Comm Ektar f/6.3 |
| #3 dial set | 1.985" | ||||
| #4 | 66.14mm | 2.604" | 2 5/8" = 2.625" | Kodak 12" Comm Ektar f/6.3 | |
| #4 dial set | 2.604" | ||||
| #5 | 85.47mm | 3.365" | 3 3/8" = 3.375" | Kodak 14" Comm Ektar f/6.3 | |
| Prontor | #0 | 34.6mm | |||
| #1 | 41.6mm | ||||
| #3 | 65mm | ||||