Film-Tech Forum ARCHIVE: Century vertical drive shaft gear

This is topic Century vertical drive shaft gear in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Dominic Espinosa (Member # 2122) on 10-11-2011, 10:51 PM:

Hey gang,

This is a new one for me.
During a show today a Century SAW decided to shear the screw holding the interface gear from the main drive to the vertical shaft (gear driven off an RCA head).

Am I crazy to hope to salvage the shaft?

Here's the carnage

Posted by Monte L Fullmer (Member # 2797) on 10-12-2011, 01:01 AM:

quote: Dominic Espinosa
Am I crazy to hope to salvage the shaft?

How important is this to YOU?

Can't you just put a new screw in after retapping the hole, or taking a easy out to remove the broken screw thread?

Looks like an easy fix on this end..

Posted by Ian Parfrey (Member # 5122) on 10-12-2011, 01:39 AM:

Agree with Monte on this. The hole appears to have little damage/wear so a quick trip to an engineering shop with a spark etcher will get that screw out in a jiffy.
Now, if the screw holes HAVE elongation, either in the shaft or the gear body, then an etch and a weld will fill the hole back to it's original shape - this is important as an elongated hole will induce slop into the whole gear train, something that should be avoided if at all possible.

With that in mind, I'd be renewing ALL the screws on the main shaft and shutter shaft just to be sure.

Posted by Richard May (Member # 2627) on 10-12-2011, 11:35 AM:

You should be okay with a new screw. There are no threads in the shaft. I had this happen before.

Posted by Louis Bornwasser (Member # 3063) on 10-12-2011, 12:48 PM:

No screws inside the shaft is correct. Replace the screws with hex head screws like Hollo-Krome. They are very strong. This is important since they rely on clamping action to stop any motion between the gear & shaft. The old screw, if loose, will break upon tightening. louis