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View Full Version : Bogen Tripod Leg Slipping Fix



JoeVanCleave
07-16-2006, 12:43 PM
I've had my Bogen model 3221 tripod for many years, and it's served me admirably, but for one fault: after a few years, the leg locking lever began to slip. That is, they would rotate themselves loose, against the spring tension (1st picture).

After disassembling the locking lever mechanism several times, with little success in finding the root cause to the problem, I finally discovered the cause: the surface finish of the plastic mating surfaces wears down too smooth. There's a helical-shaped mating surface, between the locking lever and the body of the leg clamp (2nd picture). These surfaces were originally a mottled, textured plastic, which provided enough grip so as to not rotate loose under spring tension. After years of exposure to fine, sandy grit, these surfaces wore down so smooth that they no longer have enough friction to stay locked.

The fix: I fashioned a double-side split-ring washer using 200 grit sandpaper (3rd picture). I cut two circles of sandpaper, sized to fit in the recess of the leg clamp block. These were then glued back-to-back, using wood glue, and the centers punched out with a 1/4" hole punch, Finally, they were cut open to form split washers.

These washers are installed between the locking lever and the leg clamp block, to provide a high-friction grip between the two mating surfaces (4th picture). After finishing this upgrade, I have had no more problems with slipping legs, even under the heaviest of loads. Best of all, should the sandpaper discs ever wear down to the point that slipping starts to be a problem, I can just install new ones. Attached files http://f295.f295.org/uploads/dsc00937a_3262.jpg (http://f295.f295.org/uploads/dsc00937a_3262.jpg)

JoeVanCleave
07-16-2006, 12:45 PM
2nd picture, showing locking lever with worn mating surface. The corresponding mating surface in the leg block is also worn down smooth.

Attached files http://f295.f295.org/uploads/dsc00941a_3748.jpg (http://f295.f295.org/uploads/dsc00941a_3748.jpg)

JoeVanCleave
07-16-2006, 12:47 PM
3rd picture. Two sandpaper discs, cemented back-to-back, center hole punched and split open, form a high-friction fit between the two worn mating surfaces.

Attached files http://f295.f295.org/uploads/dsc00942a_9019.jpg (http://f295.f295.org/uploads/dsc00942a_9019.jpg)

JoeVanCleave
07-16-2006, 12:50 PM
4th picture, showing leg locking lever with installed high-friction split washer. When reinstalled inside the leg block, the leg locking mechanism operates just like new.

Attached files http://f295.f295.org/uploads/dsc00939a_5834.jpg (http://f295.f295.org/uploads/dsc00939a_5834.jpg)

Greg_E
07-16-2006, 01:47 PM
You can also get a very serviceable repair by replacing the knobs and washers with new parts. It's important to replace the washers because they may not actually be flat. Often they use a cupped design, which of course increases the pressure on the mating surfaces.

epatsellis
01-28-2007, 02:13 PM
Otherwise known as belleville washers, or alternately belleville springs; readily available in different forces from McMaster, among others.


erie

murrayatuptowngallery
01-30-2007, 12:58 PM
I used to call them Baskerville washers, after The Hound of Baskervile, at work, when we had problems with a product that used them.