Film-Tech Forum ARCHIVE: Strong Lense Turret

This is topic Strong Lense Turret in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008547

Posted by Paul Stevens (Member # 4016) on 03-05-2007, 12:40 AM:

I have been trying to figure out why some lens mounts rock at bit when moved. After disassembling one assembly to have a close look, I found two hardened steel rods on either side of the cast metal lens housing. A thrust screw in the middle drives the housing back and forth for focus. What can be done to make the focus assembly move more easily without rocking or binding?

Also gate tension indexer needs to be free'd up as well. Another disassembly here?

Paul Stevens

Posted by Monte L Fullmer (Member # 2797) on 03-05-2007, 03:06 AM:

What breed of Simplexes do you have? P-1050's or Milleniums?

TU-2000 turrets aren't the best animal ever created, but I cant say much since I have to babysit 24 of them, and some that had the same condition, so here goes:

1st - around the turret ring there are three small bearings, and usually the lowest one will blow a tire due to the weight of the turret disc. One takes an 1/8" allen to take out the allen on the side. Then, take out the allen stud that has the bad bearing and with the disc play, you can remove that bad bearing and replace it with the new bearing. Then just tighten up the two allen screws.

2-the top bearing is on an eccentric shaft to where you have to do is loosen up the inset allen setscrew on top of the turret, and then take the larger allen and turn that screw to raise or lower the bearing down on the disc so that slight contact is made so to make the turret disc have full contact with the other two bearings.

3-If bearings and disc are solid, then it's the lens holder itself that is your problem. on the right side of the lens holder, there is this strip of spring steel that rests against the horizontal adjustment shaft (and this shaft loves to lose its spring after awhile where one had to rebend that spring steel downward a bit, with the lens assembly out of the disc), and if this spring steel strip is loose, this'll cause the lens holder to flop around since there is no tension to hold it..

Like I say, TU-2000 turrets arent the best, but if you got an bend for mechanics, you can make these turrets work the best for you..

good luck-Monte

Posted by Tristan Lane (Member # 1169) on 03-05-2007, 10:45 AM:

Monte,
Based on his description, I would think he is referring to TU2020 turrets. The lens barrel on the 2000 turrets is pretty solid and rides on one large steel shaft. He mentioned two.

I think he has the same problem almost any 2020 turret will end up having over time.

Paul,

First off, what model of projector is this?

On newer versions of the TU2020 the lens barrels were fitted with two set-screws that applied pressure to one side of the housing, literally squeezing the part that rides on the two steel rods together and tightening up the slop. I'm assuming you don't have these adjustments, or you would have noticed them and adjusted them.

If it's an older version of the turret, there's not much you can do to remove the barrel movement, other than by removing the lens barrel, loosening the two screws that attach the rods to the lens plate, and spreading them out with what little play the mounting holes allow. Then, test fit the barrel assembly.

If all else fails, you can insert wooden dowel material between the rod and the housing (think q-tip). This will temporarily alleviate the problem until the wood gets compressed again.

This is my biggest complaint with these turrets.

Posted by Paul Stevens (Member # 4016) on 03-05-2007, 04:16 PM:

They are Milleniums.

The rotor disk works fine. The lock pin assembly had to be free's up at bit with some oil.

I thought I might be fighting the friction locks but after loosening them it did not loosen the focus rails up much. Perhaps the cast metal just takes a set and must be forced open a little.

Posted by Mark Gulbrandsen (Member # 72) on 03-05-2007, 05:05 PM:

Strong unfortunately does not use synthetic anything.... just the cheapest grease thay can get. Its best to clean off all the old residue of the old lube that has dried up and re-lube with something synthetic... say Mobil-1 wheel bearing grease. This stuff won't dry up on you.

Mark

Posted by Eric Robinson (Member # 2966) on 03-06-2007, 01:19 AM:

I have had to disassemble and reassemble all of my lens barrel slides and relube them. After this process they work great. It seems like each new design has some type of flaw. I'm sure any machinist cringes when they encounter this design which has adjustments to bend a chunk of metal for increased tension. Hmmm what happens when the metal bends back and forth too many times?