Film-Tech Forum ARCHIVE: Play in Simplex XL focus knob

This is topic Play in Simplex XL focus knob in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by David E. Nedrow (Member # 4981) on 08-31-2010, 01:43 AM:

I have about a quarter inch of play in the focus knob on a Simplex XL. In other words, I can turn it back and forth with a travel of 1/4" before meeting any resistance.

Any thoughts on how to correct this? My assumption is that the focus knob should change the focus with any amount of movement.

-David

Posted by Mike Frese (Member # 4361) on 08-31-2010, 01:06 PM:

I am having the same issue as well!

Posted by Randy Stankey (Member # 64) on 08-31-2010, 01:19 PM:

You're generally right. There should be little or no play in the knob but it's not critical that there be no play at all. A little bit is not a problem but a quarter turn is too much. However, it's difficult to describe all the sources of play.

First, check to see that the knob is properly fixed on the shaft. See that the set screw that holds it onto the shaft is properly tightened and that the knob, shaft and screw are undamaged.

After that, follow the mechanism through, looking for sources of play: Loose, damaged or worn parts. Again, I can't describe all the things that you need to check in a short message. You have to do a little snooping and use common sense.

Do you have a manual with a parts diagram? Check your manual. If you don't have one, download it from the Manuals section of this site.

If you haven't already done so, you should make friends with your manual! [Wink]

Posted by Randy Bowden (Member # 587) on 08-31-2010, 05:50 PM:

It sounds like the flanged focusing screw is loose (p-1534) it has 2 screws holding it to the lens barrel. Check the bolts up front as well.

Posted by Tony Bandiera Jr (Member # 2365) on 09-02-2010, 01:39 PM:

David, to expand on what Randy said, remove the two allen head screws, and turn the black flange piece to take the slop out of the lens adjustment. I can do it in person easily but am struggling to think of how to describe it in a post...

Posted by David E. Nedrow (Member # 4981) on 09-02-2010, 06:45 PM:

Thanks all. I'm going to take a look at it tonight or tomorrow. I'll let you know what I find/do.