Film-Tech Forum ARCHIVE: 6k reels...do I need floating hubs or solid?

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Posted by Celine Negrete (Member # 5531) on 03-16-2010, 10:03 PM:

We build our prints onto two 6k reels. We have one Simplex E7, and our screenings have an intermission so that we can thread the 2nd reel.

Anyhow, I am looking to purchase a couple more 6k reels but am not sure of the difference between floating hubs vs. solid. The reels we have now are Goldberg 5/16" with floating hub (each outer ring can spin independently). I saw a couple of solid hub reels on EBay.

Is there a reason why I need to stay with floating??

Thanks!

Posted by Jeremy Weigel (Member # 4208) on 03-16-2010, 10:50 PM:

I believe you'll want floating hubs at least for the take up. It lessens the inertia as to not snap the film at start up and then when the outer flanges get up to speed they provide momentum. At least that is what I was told.

Posted by Joe Redifer (Member # 3) on 03-16-2010, 11:19 PM:

Just as long as you always take up onto floating hub reels, there is no reason you can't feel out from a solid hub.

Posted by Monte L Fullmer (Member # 2797) on 03-17-2010, 01:32 AM:

True - the floating hub takes the "flywheel effect" of a driven spinning reel away since the hub itself is doing the initial rotation and the flanges that are not connected to the hub, have to catch up speed with the hub.

This reduces the start torque created if the reel was a solid reel which would snap film on takeoff due to the massive torque created with the "flywheel effect" of both flanges being in the same rotation speed with the hub.

Only small danger if you use solid reels on a feed is that when the reel is picking up decent rotational speed, the film tension heading down to the upper sprocket is increasing towards the hub due to, once again the "flywheel effect" putting a torque load on the hub of the reel, which could stretch out sprocket holes, esp with the E-7 having only a 16 tooth upper sprocket.

This is where the XL units have it made with big reels due to the larger 24 tooth sprockets to lessen the pull load on the film.

-Monte

Posted by Paul Gordon (Member # 3320) on 03-17-2010, 08:25 AM:

Also bigger the floating hub the better... look for 8" floating hub reels.

Posted by Scott Norwood (Member # 30) on 03-17-2010, 08:52 AM:

What Paul said.

Get 7" or 8" floating hubs if at all possible. Fixed hub reels are usable for feeding, but can be rough on the beginning and end of each reel if you aren't careful when rewinding them (by slowly increasing the speed as the reel starts to rewind).

I don't know why people order 26" reels with 4" hubs--the 4" hub only gives an extra few hundred feet of film capacity, but substantially increases the potential for film damage.

Note that all of the above applies to conventional feed and takeup mechanisms. I suspect that large fixed-hub reels would be fine for both feed and takeup on machines which provide constant tension on the film (e.g. Kinoton E-series), but they would still require care when rewinding.

Posted by Celine Negrete (Member # 5531) on 03-17-2010, 09:42 AM:

Thanks for the information. It sounds like floating is the way to go...especially with mention of 'slowing increase the speed' for the rewind. We have "on" and "off" with our rewind table. So, there is no slow increases of speed.

Also, our current reels have the 4" hubs. To be honest, we often show films that are over 2 hours long and we are pushing the limits of the reel at that point. I would be afraid the larger hub reels would make it difficult for us if we regularly find ourselves at the 'end' of the reel with the 4" hubs. "The White Ribbon" is coming up and I am worried whether or not we can make it onto 2 reels, for example.

Posted by Mike Croaro (Member # 3123) on 03-17-2010, 07:06 PM:

I doubt you can put "The White Ribbon" on two 6000 reels. The film runs 2.5 hours. Excellent film by the way.

Mike

Posted by John Wilson (Member # 269) on 03-17-2010, 07:19 PM:

8 Reels and 144 minutes...it is possible, if the end of 4 is about half way through.

Posted by Celine Negrete (Member # 5531) on 03-17-2010, 07:54 PM:

Yes, that is what I am hoping for....the end of reel #4 being halfway through! We have done it before but the reels needed to be all about the same size. Won't know until 2 days before it opens (when the print arrives).

But....I am having a heck of a time finding them! Any ideas? I searched EBay and only found solid hub. Googled them and could only find 2k or 'wall art' for you home theater (gold-plated reels, etc). I posted in the 'wanted' forum of film-tech also. But still no leads.

Posted by Monte L Fullmer (Member # 2797) on 03-17-2010, 08:42 PM:

You could head to this page for used booth equipment. Heard that they're not too bad for used equipment and parts needed.

quote: Scott Norwood
would be fine for both feed and takeup on machines which provide constant tension on the film

If those E-7's had the variable tension "cone" clutches that came with the deluxe setup for the XL projector package on the takeup spindle (in which they don't), then you could get away with solids on the takeup. But, if the clutch is the old fashioned single tension clutch with the felt pad between the drive and driven plates, then it's highly advisable to use floating for the takeup since the film tension is the tightest when the takeup reel is empty, then the tension is much lesser when the reel is almost full.

The old Cine V-18 large reel transport along with the 2X4 and 4X4 Cine towers had the variable cone tension setup for the takeup spindles. But even then, the stock Cine 13k reel, the takeup reel had the larger 10inch insert was used for takeup to reduce the rotational torque.
Good luck - Monte

Posted by Ian Parfrey (Member # 5122) on 03-17-2010, 11:00 PM:

"The White Ribbon" should comfortably fit on two 7000' Goldberg E-Z-Hub spools. We had a couple of 7000' spools and the came in handy as we had a two projector changover setup and they j-u-s-t fit in the Century magazines.

Check out the 7's Celine, they sound like what you are after.

Posted by Monte L Fullmer (Member # 2797) on 03-17-2010, 11:31 PM:

7k reels are about 28 inches in diameter.

she would have to measure the radius length from center of spindle to base and spindle to underneath the soundhead to see if there is any clearance.

I'd be just safe to use 3, 6k reels for that one movie. Mount three reels each on two 6k reel and one 6k reel to carry the other 2 reels.

Safest way to do large movies on a 6k reel changeover house.

-Monte

Posted by John Wilson (Member # 269) on 03-17-2010, 11:42 PM:

Yes, but she only has one machine and needs only one intermission, hence packing the reels full as they can go.

Posted by Michael Brown (Member # 890) on 03-19-2010, 06:33 PM:

Back in my days at a university cinema we were using, I think they were 34 or 36 inch reels. You could get up to about 2 and a half hours on one reel. Fixed reel for the pay out and a floating hub reel on the take up. With that capacity we generally could fit ads, trailers and a full feature on the one reel, only needing an intermission for longer titles.

Posted by Celine Negrete (Member # 5531) on 03-20-2010, 01:20 PM:

Just and update....we have more reels now (thank you!). 24" and 26", all floating hubs. So, I think we are set for anything that might come up!

And, thanks for helping me to understand the difference between floating and solid!