Sinar F2 rail holder twisting

[Basset]

Hi

The lens rail holder twists sideways when I tighten gently, so that I have to compensate on the spirit level by guesswork. I've stripped and buffed everything up but it is still the same. It used to be fine, is this a common problem, would a second hand holder have same issue. Not sure if you can still get plastic ring parts - many thanks.

Basset

[Basset]

Hi Sorry I just meant main rail holder

[Bernice Loui]

Remove the plastic ring, check to see if the ring is cracked and does not come apart as a complete circular ring. If it is a complete ring, it is possible the ring has changed dimension. There is a small slot which allows the ring to compress against the rail. If the gap is not present when the ring is on the rail, there will be little if any rail clamping force. Either replace the ring or try enlarging the gap with great care. Bending or flexing the ring excessively can break it rendering the ring scrap-recycle.


Bernice

[Bob Salomon]

Hi

The lens rail holder twists sideways when I tighten gently, so that I have to compensate on the spirit level by guesswork. I've stripped and buffed everything up but it is still the same. It used to be fine, is this a common problem, would a second hand holder have same issue. Not sure if you can still get plastic ring parts - many thanks.

Basset

Leica owns Sinar, contact them for availability of spare parts.

[Rick Rosen]

My Sinars always did this twist when you tightened it. I am guessing it is because when you tighten the slit in the plastic ring around the rail compresses closed. I solved the issue by always holding the top of the camera frame when tightening.

[LabRat]

Or if for leveling, leave it locked and just use the side leveling on your tripod head...

Steve K

[Bernice Loui]

That plastic bushing is Knackered.... if your Sinar rotates even a tiny fraction of a mm, that plastic bushing is done. Replace it or increase the size of the slot.

Over three decades of using a Sinar from 4x5 to 8x10 with BIG lenses and more, they do not move at all once properly locked and all the parts involved with locking is in proper working condition.



Bernice



My Sinars always did this twist when you tightened it. I am guessing it is because when you tighten the slit in the plastic ring around the rail compresses closed. I solved the issue by always holding the top of the camera frame when tightening.

[asf]

This is called creep, all Sinars I've ever used had this problem while tightening the rail clamp. The rail clamp 2 was slightly better but it didn't (and couldn't) completely solve the issue. Sinar made 2 versions of a geared rail clamp that solved the problem but one is huge (Vaplo?) and the other is for the p3 system and works differently (rail extensions are attached to either end). Both are very rare.
Level with a geared head instead of with the rail clamp.

[Basset]

This is called creep, all Sinars I've ever used had this problem while tightening the rail clamp. The rail clamp 2 was slightly better but it didn't (and couldn't) completely solve the issue. Sinar made 2 versions of a geared rail clamp that solved the problem but one is huge (Vaplo?) and the other is for the p3 system and works differently (rail extensions are attached to either end). Both are very rare.
Level with a geared head instead of with the rail clamp.

Hi

Many thanks for all replies. The head locks fine but spirit creeps (as pointed out) when locking, but never used to. The plastic bush looks unmarked, I will simply overcompensate before tightening and put up with it as my Gowland does not even have a spirit level. I have seen a spare plastic bushes for £24 not really worth it. I do not use a head, you do not need one if you can adjust/ roll camera left and right as with Sinar clamp. I just plonk everything on a Manfrotto Carbon tripod 190 I think (not the heavier 055) and fiddle with back legs. It sounds disastrous but works fine (up to 480mm Apo Ronar lenses or with Sinar Shutter for 360mm barrel) just do not walk with it set up.

Best - Bassett