Film-Tech Forum ARCHIVE: Ultramittent bearing upgrade

This is topic Ultramittent bearing upgrade in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Randy Bowden (Member # 587) on 10-24-2007, 11:41 AM:

Here is my upgrade for the horrible outboard bearing design on the Christie Ultramittent. One of the most common reasons for failure on this intermittent is due to the fact that the inner bearing race will slip against the starwheel shaft, resulting in the bearing wearing a groove into the shaft, I see this a lot in my shop, sometimes it's very extreme. This doesn't come as much of a surprise considering that the surface contact area for the bearing only measures aprox. 3mm wide, my upgrade takes it to aprox 9-10mm wide. I marked with a sharpie pen on two separate starwheels to illustrate the difference. I've done hundreds of rebuilds like this and have yet to have one come back with any apparent wear issues. The replacement bearing is pressed in flush against the back side of the bearing plate, I coat the inside of the bore with high strength Permabond retaining compound, so the bearing isn't going anywhere. Bearing part number is 88038.

Posted by Mark Gulbrandsen (Member # 72) on 10-24-2007, 07:04 PM:

Thanks Randy for that tip... I will also do that on future rebuilds. Is that 88038 an ABEC7 or just an ABEC 3 bearing? Also, isn't that the bearing that was used on the outboard side of the star of the motiograph AA movement? Any ideas on a bearing for the outboard cam side?

Mark

Posted by Randy Bowden (Member # 587) on 10-29-2007, 02:56 PM:

I'm not sure about the ABEC Rating. I would have to ask my supplier. On the cam side I use a dual rubber shielded bearing as well, part number DDRIF1438.