8mm Forum: BOLEX 18 - 5 Flat motor belt

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Posted by Robert Tucker (Member # 386) on March 18, 2009, 05:53 PM:

Was wondering if any one knows where i can get a flat motor belt for a first series Bolex 18-5?

Rob.

Posted by Douglas Meltzer (Member # 28) on March 19, 2009, 11:09 AM:

Robert,

It's tough to find those flat belts. This UK dealer might have what you're looking for.
http://vintagecine.co.uk

Doug

Posted by Robert Tucker (Member # 386) on March 19, 2009, 03:25 PM:

Hey well i suppose some times it can be fun, thou bloody hard. Thanks for your tip as i am on the case!

Cheers Doug!

Posted by Paul Adsett (Member # 25) on March 19, 2009, 04:52 PM:

I replaced my 18-5 flat belt with 3 rubber o-rings. It's been running fine that way for over 15 years.

Posted by Bryan Chernick (Member # 1998) on February 04, 2012, 06:57 PM:

Has anyone converted an 18-5 from the flat belt to the 3 round belts? I have a machine that I'm using for spare parts that has the pulleys for the 3 round belts. Can I just swap the parts over or is there anything else that needs to be done? If anyone can give me some pointers before I start tearing into these projectors it would be much appreciated.

I just picked up an 18-5 at a sale for $15. It has the extra sprocket on the bottom, the red power switch and a worn out flat belt. It appears to be in great condition other than the belt problem.

Posted by Bryan Chernick (Member # 1998) on February 12, 2012, 02:09 PM:

To answer my own question, there is a lot more to it than just swapping the pulleys. In order to remove the large pulley you have to remove the entire shutter assembly and many of the drive gears. Once I got it out I found that the I could not get the smaller pulley removed from the motor. After loosening the screws it would not budge. It felt like I was going to cause damage to the projector if I put more force to removing it. As for the large pulley I could not see how it would come off the shaft that has the shutter and worm gear. It looks as thought that is all one piece. all of this dis-assembly was done on the parts projector so I didn't do any damage to the one I was trying to fix.

I abandoned the plan to swap pulleys and went back to the worn out flat belt. This belt was slipping and not driving the projector at all. I removed the belt and cleaned both pulleys with rubbing alcohol. I soaked the belt with Roller Rejuvenator and reinstalled it. I greased all the gears and oiled the shafts. It worked good for several movies but I think it may be running a little slow. The belt may be slipping on the motor pulley a bit.

It works for now but I'm still going to have to come up with a belt replacement somehow to keep this projector going. It seems to me the o-rings may slide off the pulleys easily but if that has worked for others that may be the way to go.

Posted by Janice Glesser (Member # 2758) on February 12, 2012, 02:39 PM:

Robert...Do you think this might work?

BELT MATERIAL KIT. We can also supply you with flat rubber belt material..make your own belts. Available in 3/8 inch width..width easily shortened by cutting with scissors or an exacto knife..three feet belt material in a kit...material is joined with a candle flame..kit is... $10

http://www.urbanskifilm.com/projectors.html

Posted by Barry Fritz (Member # 1865) on February 12, 2012, 08:15 PM:

I've got a conversion kit for switching the pulleys and the instructions on how to do it, but can't find the instructions...just the old pulleys. I do recall in reading them that it was not a walk in the park to swap.
I have two of these that still have the single flat belt and on one of them somebody put a piece of rubber or neoprene tube over the small pulley. The I.D. is just a little smaller than the O.D. of the small pulley so it is really tight and does not slip. The wall of the tubing is very thin so it doesn't increase the pulley size much so the speed isn't affected. It does afford better grip and tightens the belt because of the slight increase in size.

Posted by Bryan Chernick (Member # 1998) on February 20, 2012, 09:17 PM:

My flat belt started slipping again. I think it's just too far gone but I think I came up with a solution. I took Paul's advice and installed 3 of the square O ring type belts. I turned it by hand and noticed that one of them kept wanting to creep off the motor pulley. I think that could do some damage to the shutter wheel if that happened when it was running.

My solution was to use some contact cement and brushed a little between the belts. I did a small section at a time with the belts installed using the gap between the pulleys to apply the cement. After each section dried enough, about 10 minutes, I turned it an glued the next section being careful to not get cement on other parts of the projector. I made sure that the belts were pressed together good at all times. I then let the glue dry for 24 hours. Everything seems to be running good now but time will tell if this is the real solution.

Posted by Janice Glesser (Member # 2758) on February 20, 2012, 10:30 PM:

That was very creative Bryan...I hope it turns out successful in the long haul [Smile]

Posted by Bryan Chernick (Member # 1998) on February 22, 2012, 12:49 PM:

While watching a 300' film last night one of the belts slipped off the large pulley. The projector started making a rattling noise but I don't think anything was damaged. The glue didn't hold. I think I'm going to try some of that 3/8" belt material from Urbanski that Janice pointed out. Has anyone used this belt material?

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