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jerryg
Joined: 04 Apr 2017
Posts: 74
Location: spokane wa.
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 Posted: Sat Jan 23, 2021 7:29 am Post subject: rb auto loose focusing rack |
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| i have a 3x4 and 4x5 auto rb, they have the two focusing knobs, and they both are loose to where when the camera is moved the lens will move on it's own. any neat tricks to adding a little tension to the knob to keep the lens from running away on it's own lol |
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45PSS
Joined: 28 Sep 2001
Posts: 4081
Location: Mid Peninsula, Ca.
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| Posted: Sat Jan 23, 2021 5:01 pm Post subject: |
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Remove the rail guide blocks and the rail from the bed. The focus pinion should now lift out.
Inspect the gearing on the bottom of the rail and the pinion for wear. There is likely a brass spring on the underside of the focus pinion that may be compressed.
The body focus should be similar in build. The bellows are attached to the body with a frame and 4 screws if memory serves correct and easy to disengage from the body for servicing.
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The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU. |
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jerryg
Joined: 04 Apr 2017
Posts: 74
Location: spokane wa.
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45PSS
Joined: 28 Sep 2001
Posts: 4081
Location: Mid Peninsula, Ca.
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| Posted: Sun Jan 24, 2021 7:50 pm Post subject: |
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I see some wear on the pinion in your first photo. The focus knob is attached with a taper pin, drive it out from the small end. Put a .010 to .020 shim between the knob and the side mount or between the side mount and the bed to pull the pinion over to an unused section of the pinion to the rail.
use a light amount of grease on the pinion and its pivot points.
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The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU. |
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jerryg
Joined: 04 Apr 2017
Posts: 74
Location: spokane wa.
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| Posted: Mon Jan 25, 2021 1:03 am Post subject: |
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thank you 
always great help |
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