Korona 11X14 Front Rail Replacement Ideas

[OKAROB]

Last summer I purchased a Korona 11X14 camera bones missing a few key components for a great price (Minus a back, bellows and the front extension rail.) I have nearly finished the camera with the exception of the front extension rails. I am pretty handy with wood and woodworking tools so it is the geared rails that are attached to the wood extension rails that I need ideas for. I looked at other extension rails for sale but like the film holders and backs there is no standardization among the various manufactures nor within the various camera models of different sizes. One would think that a manufacture would standardize on one size and pitch for racks and pinions.

I have looked at McMaster/Carr and various manufactured racks and pinions available on ebay but have not found a suitable replacement of a similar size and at a reasonable price. I would like to hear how anyone else has solved the extension rail replacement issue or how you have created a new method to move the front standard backwards and forwards for focusing. Thanks, appreciate your ideas.

Robert

[Michael Roberts]

Hi Robert,
I had nearly the same problem some 15 or so years ago. I bought an 11x14 Empire State that had the front rail, but no back rail. I found a local woodworking shop and found some old, wrong-sized orphan rails on eBay the pro woodworker could cannibalize to use on the new rail. You just have to match the pitch, etc., of the gears on the camera. I happen to have some parts from an old Korona 5x7. I'll check and see how much of the rail I have. It's yours if you want it.

Another idea is to forego the rack and pinion for the new rail. Just make the rail with the groove on the sides. Use friction focusing (instead of rack and pinion) and the already-in-place locking mechanism on the Korona front standard to lock the front standard in place when in focus. This is what I would do today, assuming the front standard will lock down tight.

Update: The two tracks are 14 1/4" long.

[Tracy Storer]

Mcmaster has gear rack in acetal plastic for a fraction of the steel or brass prices. (you DO need to correctly identify the pitch and pressure angle though)

[OKAROB]

Michael, thank you for the offer of your spare parts. I have decided to go with buying matching modulus spur gear and rack from China. I am trying .5 Modulus for the metric equiv for pitch. I just hope it is not too fine a modulus/pitch for the purpose of a view camera focusing/extension rail. As it is the gears on my other cameras occasionally want to jump a tooth. I chose the number of teeth so that the diameter of the spur gear was slightly larger than the original on the camera. I will have to adjust the depth of the rack on the rails as the rails available online are much deeper than the original and same for the width.

Thanks again for your offer.

Best regards,
Robert

[OKAROB]

Tracey, Thanks for the McMaster and Carr recommendation. They do not have the needed pitch and pressure angle for the older camera. The ancient gear racks are very squared-off toothed and so the modern pressure angles are hard to convert. Any way I used their filters and diagrams to choose .5 Modulus and 20 teeth to get the diameter spur gear that I wanted. Modulus 1 with the larger tooth on the spur gear was either too large or small a diameter based upon the number of teeth that were available online. Thanks for your advice/help.

Best regards, Robert

[ethics_gradient]

If you have the measurements, you could get them 3D printed (there are some exotic filaments that work well for rack and pinion assemblies). However, if you don't have the CAD skills, you'd need to pay someone to create the model for you first, which might be prohibitive.