bolex 1 to 1 drive shaft

Richard Tuohy · October 18, 2005

Hello all,

I am contemplating a bolex with a 1 to 1 drive shaft modification. I comes with a single frame JK annimation motor and the modification I assume was to fit with this motor. So what does it mean exactly? What is the nature of the drive shaft prior to modification? And am I correct in assuming that I can nonetheless use this camera in the normal wind up mode without the motor and running at normal filming speeds?

Many thanks for your advice,

Richard

Herb Montes · October 18, 2005

Hello all,
I am contemplating a bolex with a 1 to 1 drive shaft modification. I comes with a single frame JK annimation motor and the modification I assume was to fit with this motor. So what does it mean exactly? What is the nature of the drive shaft prior to modification? And am I correct in assuming that I can nonetheless use this camera in the normal wind up mode without the motor and running at normal filming speeds?

Many thanks for your advice,

Richard

Yes, you can. This was probably an older Bolex that had a 1:1 shaft added. But you can remove the animation motor and re-engage the clockwork drive to use the camera normally.

daniel mahlknecht · October 19, 2005

the 1:1 shaft is needed to atach the newer elrctric motors to the camera (it meas that one turn of the motor is one frame ), the older bolex had a 1:8 shaft (slightly more on the left than the newer one) and needed 8 turns of the motor to get one frame exposed.

you still can use the springdrive, there is a lever on the side of the camera where you can switch between spring or electric drive.

(change only when spring is not loaded, when using electric drive springdrive must be disabled, relase button must be fixed to filming position and the highest available framerate of the springmotor should be selected, you will choose the desired framerate on the electric drive, and you will also start the camera with the button on the electric drive)

daniel

Clive Tobin · October 19, 2005

the older bolex had a 1:8 shaft (slightly more on the left than the newer one) and needed 8 turns of the motor to get one frame exposed.

Actually you have this backwards. The 8:1 shaft exposes 8 frames per each turn of the shaft.

All Bolex H-16 clockwork cameras have the 8:1 shaft. Newer ones (the model 4 and up) also have the added 1:1 shaft, which is one frame per turn.

Richard Tuohy · October 19, 2005

Does that mean then that newer bolex cameras somehow have both a 1:1 and a 1:8 shaft and a camera that was modified to 1:1 (ie an older one), no longer has a the 1:8 shaft? Would this mean that it cannot be used for handcranking (a la keystone cops)?

daniel mahlknecht · October 20, 2005

the modified camera should als have both shafts, and also the springdrive should work.

Steven Budden · November 2, 2005

Also, the new tobin sync motors are designed to work with the 8:1 shaft so you can use them on older bolexes.

Steven

November 3, 2005

the 1:1 shaft is needed to atach the newer electric motors to the camera (it meas that one turn of the motor is one frame ), the older bolex had a 1:8 shaft (slightly more on the left than the newer one)

The Revolution Sync + Time Lapse + Single Frame motor for the Bolex works on the 8:1 shaft present on almost all the Bolexes.

Bolex Shafts

Direct-drive, brushless, built-in 29.970 and 23.976 'video' speeds, crystal from 1-48fps, and full crystal-controlled timelapse features.