Hi Everyone,
Here is an aluminum lens board 4×4 inches. It has a raised rib just inboard of the edge. The hole is 34mm, for a Copal 0 shutter. I do not have a Calumet camera to test the fit of the board. It came with a Caltar lens, so Calumet is a good guess.
$14.00 including First Class US Postal Service shipment to a USA address. Please contact me if you have any questions. Thanks!