Film-Tech Forum ARCHIVE: take up belt for kelmar reel arms

This is topic take up belt for kelmar reel arms 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=011493

Posted by Bernie Anderson Jr (Member # 410) on 08-02-2013, 05:43 PM:

Hi Guys,

For years, I've been using roundthane as a take up belt on my RCA 9050. I'm using Kelmar hour reel arms. If I let the projectors sit for a week or two, the rounthane likes to form to the take up pully of the projector and reel arm where the belt is no longer smooth, plus it likes to stretch over time and then it slips on take up.

People have told me to use a V-belt instead, so I decided to try it out, but I'm having a hard time finding a suitable replacement. I'm tried an 3L540 and it worked but was very floppy, so I switched to a 3L530. Although, it fits, its very tight and I'm afraid to put pressure on the bearings of the soundhead and the reel arms. It seems I need a 53.5 inch belt, which they don't make.

My take up arm does not have an idler pully on it like some I've seen and even if I tilt the arm forward a little, the belt will hit the casting of the soundhead.

Any thoughts on this or suitable replacement for Rounthane? Or am I stuck with this stuff?

Thanks

Bernie

Posted by Louis Bornwasser (Member # 3063) on 08-02-2013, 08:58 PM:

Use the longer belt. Then, using longer screws, space the entire arms downward, using thick flat washers as spacers.

You will get an exact fit with the correct number of spacers.

Easy. Really! Louis

Posted by Bernie Anderson Jr (Member # 410) on 08-02-2013, 11:04 PM:

Boy I feel dumb. I didn't think of that. So its not me, its a common problem then?

Posted by Louis Bornwasser (Member # 3063) on 08-03-2013, 07:08 AM:

Most people just used the round belts. Vee belts require some form of tightening procedure since they too will stretch a little. Keep a few extra flat washers handy for later in case. If you do this, the belt will outlive us all.

Some adjustment can be made by changing the angle, unless you have very large reels. This method is very common on RCA/Simplex style soundheads. louis