Protar VII F set - Compound Conundrum

[karl french]

I recently picked up a nearly complete Protar VII F Set. It's missing it's Compound No. 4 shutter and Protar V (but including a 14" cell.) I have a couple spare Compound No. 4 shutters, but the problem is that barrels/spacers on the various cells seem like they should screw right in the face of the shutter or the end of the flange threads on the back of the shutter. My Compound 4/ tube 10 shutters all have front and back barrels that seem integral to the shutter. The threads on all the Protar barrels in this set match the threads of the Compound 4 barrels just fine, but the spacing would be radically off if they were screwed into the shutters I have. The individual cells are too small to screw directly into the shutter without the spacers/barrels. The two other Protar VII sets I've had were both in Ilex shutters. Am I missing something, or did B&L include a version of the Compound 4 with a short tube?

[karl french]

Conundrum resolved. Early Compund No.4 shutters (1903-1910) do not have the extended aluminum barrel at the front and rear of the shutter. The threads/barrel is flush with the face of the shutter and stop at the end of the flange threads on the rear of the shutter. This orphaned Protar VII F set now has a home.