New Products: Crystal Motors for Bolex H-16, H-8

Clive Tobin · October 31, 2005

Two new Tobin motor models are available for driving Bolex H-16 and H-8 cameras that were made after about 1966, and are fitted with the 1:1 drive shaft.

The TXM-20Ba has USA speeds and the TXM-20Be has European speeds. Both motors have a more powerful motor than the previous model TXM-20, which has enabled removing the gear train formerly needed. This gives much quieter running and possibly improved long-term reliability.

The TXM-20Ba has speeds of 12, 15, 24, 30, 48 and a possibly usable unmarked 60 FPS. The TXM-20Be has speeds of 12.5, 25, and 50 FPS and two intermediate speeds. Operation is on 12 volts DC, and sockets are provided for MM and WM magazine torque motors and for accessory Milliframe and Videoframe Controllers.

For additional details kindly refer to the catalog page which is at http://www.tobincinemasystems.com/page26.html .

andrewbuchanan · October 31, 2005

Clive,

Good to hear about these motors. Is the K3 a 1:1 shaft? I've been looking for something to strap onto a K3 for a crash-cam and I'm wondering if these would work? Any plans for another K3 motor?

Clive Tobin · October 31, 2005

Clive, Good to hear about these motors. Is the K3 a 1:1 shaft? I've been looking for something to strap onto a K3 for a crash-cam and I'm wondering if these would work? Any plans for another K3 motor?

We are sold out of K-3 motors, Du-All bought the last ones and may still have some. Although a lot of people talk about buying these motors, few actually do so and I am dubious about making yet another model.

The K-3 after modification does have a 1:1 shaft. The TXM20-K was of course designed to fit on the K-3. The TXM-20Ba is a similar product but the shaft and mounting are different, and the case does not have cutouts to clear the knobs on the K-3.

Installing even the correct motor is a real pain which you can read about here: http://www.tobincinemasystems.com/page75.html

Because of the high installation cost (unless you do it yourself) you may well find that it will be cheaper overall to buy an old Bolex with 8:1 shaft for $100 and our TXM-26B crystal motor.

Clive Tobin · November 3, 2005

There is now one up on auction at you know where. If nobody bids against you it could be yours for $9.95.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...item=7559627660

November 10, 2005

Instead of a K3 for a crash cam, consider using a Kodak K100. Cheap to buy, very small, with a 108 second run on one winding (which may make fitting a motor unnecessary), AND a motor shaft should you need to use a motor. One of Clive's Bolex motors should be easy to adapt.

Clive Tobin · November 11, 2005

Instead of a K3 for a crash cam, consider using a Kodak K100. Cheap to buy, very small, with a 108 second run on one winding (which may make fitting a motor unnecessary), AND a motor shaft should you need to use a motor. One of Clive's Bolex motors should be easy to adapt.

The K-100 used to require a special shaft (with a gear on the end) installed in order to be able to use an external motor. I have no idea what the gear specs were, or what RPM it would want. If this could be determined, then one or the other of our motors should work maybe. If anything, the K-100 might take less power to drive as the film gate tension was varied according to running speed, giving less drag on the motor at lower speeds.

Seems to me the camera exposes 40 feet on a winding, which is just over 60 seconds if it is running at an accurate 24. The one I used to have kept getting the speed dial bumped accidentally, so the speed was off quite often.

November 11, 2005

With the K100, when you remove the drive shaft cover, there is a recessed but fairly accessible shaft which I believe could be joined to a Tobin motor with a short collar. If I remember correctly, the shaft is flattened or "keyed" on one side as you would expect. I believe the accessory shaft was was needed for Kodak's dedicated motor. I have the accessory shaft but have never, ever seen the motor. I would have to get out my K100 (a very spiffy little camera sporting a compact 17-85 zoom with built-in reflex viewfinder) to confirm this, but I believe that the shaft turns once for every 2 frames, so a Tobin motor would be set to 12 fps for normal 24 fps shooting. I have no idea if this would actually work, but it sure looks like everything's there.