Unusual Korona focus rack

[mdarnton]

I have picked up an unnatural interest in Korona camera variations lately, and have been following them closely on Ebay. Currently there are two Pictorial View models (unusual by their extending, internal back track, like Agfa/Ansco views) up there, and looking at the photos I noticed that neither has a focusing rack! On both, the place where the rack would be is smooth surfaced, obviously scratched with the type of trail a friction wheel drive would cause.

So here's my question of anyone who has or has used one: Am I right? Is this just friction drive? If so, I assume that front>back parallelism is sort of up for grabs: on the one hand, impossible to keep in parallel, on the other hand, easy to correct?

[Milonian]

I have picked up an unnatural interest in Korona camera variations lately, and have been following them closely on Ebay. Currently there are two Pictorial View models (unusual by their extending, internal back track, like Agfa/Ansco views) up there, and looking at the photos I noticed that neither has a focusing rack! On both, the place where the rack would be is smooth surfaced, obviously scratched with the type of trail a friction wheel drive would cause.

So here's my question of anyone who has or has used one: Am I right? Is this just friction drive? If so, I assume that front>back parallelism is sort of up for grabs: on the one hand, impossible to keep in parallel, on the other hand, easy to correct?

Hi,
Can't speak on the Korona specifically but I renovated a Criterion View half plate, made by the same people and very similar - and it had normal rack and pinion focusing. The assembly (metalwork) on the Koronas on eBay seems to be exactly the same as the metalwork I removed and cleaned painstakingly! The racks in my experience almost disappear into the wood frames due to oily / dust build up over 100 years or so.
On mine, prior to cleaning, it resembled an oily carpet and was stopping the assembly from running, causing it to jump. Looking at the Panoramic Korona on eBay I think the side nearest has a groove and the rack is on the opposite side. Not sure though.
The Criterion was a wreck when I got it. Jammed mechanism, no bellows etc. It's now used for wet plate at the Photography Faculty in Manchester University in England.