8mm Forum: 2580 worm gear

This is topic 2580 worm gear in forum 16mm Forum at 8mm Forum.

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Posted by Jim Schrader (Member # 9) on September 04, 2019, 10:06 AM:

Anybody have the lower gear and worm gear for sale here in the US? not looking for an expensive one as I’ll be attempting this myself I know urbanski sells them but was hoping to find a cheaper version that I can toss if it doesn’t work?

Posted by Maurice Leakey (Member # 916) on September 04, 2019, 10:44 AM:

The Bell & Howell 2580 is a great modern slot-loader, and when fitted with new gears should give many years of service.
It's a pity at the moment to try and economise. Fit the best available.
Why not try fellow member Richard C. Patchett's web-site?
http://www.rcsclassic16mm.com/bellhowell.html#MISC_BELL_&_HOWELL_PARTS

Posted by Jim Schrader (Member # 9) on September 04, 2019, 12:12 PM:

Ive has this for years and loved it so gentle on films but haven’t used it for a while I have looked and there not cheap 60.00 usd and there the aluminum inner with the nylon outer urbanskis version is all aluminum for less may have to go that route that will outlast the rest of the unit. I e got other units but have always liked this one and thought I’d try to fix it.

Posted by David Michael Leugers (Member # 166) on September 06, 2019, 02:00 PM:

Jim I have some brand new worm gears that are the original white nylon type. If you want to try I will give you one. The word is that if this type of gear has never been exposed to the wrong lube that caused all the problems to start with, and you lube it with the proper lube it should last a very long time. Let me know if you want one.

Posted by Jim Schrader (Member # 9) on September 08, 2019, 08:20 AM:

David I sent you a pm

Posted by Terry Sills (Member # 3309) on September 08, 2019, 01:02 PM:

Personally I would not put my trust in a worm gear made from two different materials. Laws of science,physics and engineering dictate that different materials have differing rates of expansion and contraction. Ridiculous idea to mount a thin synthetic skin on a metallic cylindrical base. That is surely the cause of the failure of these original worm gears, as the machine heated up during use and cooled down afterwards. Not the lubricant.

Posted by David Michael Leugers (Member # 166) on September 08, 2019, 02:14 PM:

The understanding is that the original grease used on the original worm gears made the nylon brittle which caused it to crack. Heat build up on the worm gears is minimal. While plastic materials will shrink with age, using the proper grease the worm gears will last a very long time. Bell and Howell designed great machines. They built the worm gears as they are to reduce noise. Notice that the new worm gears are built the same but with a newer and better material.

Posted by Terry Sills (Member # 3309) on September 08, 2019, 04:26 PM:

No. The most common and reliable replacement worm gears are made from a solid non metalic material. If what you insinuate about the lubricant being the determining factor, then why have so many failed. I doubt that a few projectors, if any, have had the lubricant changed in their lifetime, so that theory does not hold true. Are you saying that Bell &Howell used the wrong lubricant in the first place?
Rubbish.

Posted by Simon McConway (Member # 219) on September 08, 2019, 04:37 PM:

Worm splitting is not caused by wrong lubrication.

Posted by David Michael Leugers (Member # 166) on September 08, 2019, 06:20 PM:

I have two projectors with the replacement worm gear and I have a new replacement worm gear I purchased from Richard Patchett at the Cinevent in Columbus. All three have an aluminum main body with the black new type of plastic on the outside for the threads. Then these must be rubbish and I should bin them all... too bad, my projectors have been going strong for years now. BTW, I read a report once that Bell and Howell had come out and said they had used a lubricant that proved unsatisfactory in the long run causing the worm gears to crack prematurely. Hence the idea that a NOS worm gear installed and using the newer grease would last. It would be interesting to see a test.

Posted by Terry Sills (Member # 3309) on September 09, 2019, 03:29 AM:

I have a 1698 in mint condition, completely original and little used. The worm is perfect. The projector has always been stored in ideal conditions and I attribute the stae of the worm to these ideal storage conditions. If lubricant is the cause of failure it doesn't relate to my machine. If mine fails I would not consider a two part constructed worm. Common sense and history would dictate that a worm constructed of two completely different materials is more likely to fail than one made from a single material. As for the argument that Bell&Howell went the route they did for quieter running, then why on Earth didn't they make the worm from solid nylon/ synthetic material, as are the most popular and reliable replacement worms available today.

Posted by Simon McConway (Member # 219) on September 09, 2019, 04:05 AM:

Exactly. I have a worm gear never fitted to a projector, never used, never lubricated. It has cracked over time. This highlights the issue is nothing to do with lube.

Posted by Maurice Leakey (Member # 916) on September 09, 2019, 04:08 AM:

It is my understanding that the black one-piece nylatron worm gear was actually designed by a Bell & Howell engineer in later years.
Obviously, he also knew something.

Posted by Terry Sills (Member # 3309) on September 09, 2019, 03:06 PM:

Once again Maurice's research nails it. Jim - don't waste your money on cheap options. As my old Gran used to say - 'Cheap dear!'

Posted by David Michael Leugers (Member # 166) on September 09, 2019, 06:39 PM:

So obviously there are worm gears made of solid plastic, I have never seen one. Yes, that wood be a better solution as long as there are no other issues with them. Have any of the new black plastic two-piece worm gears cracked?

Posted by Jim Schrader (Member # 9) on September 09, 2019, 09:38 PM:

I’ve ordered up the all aluminum version along with the nylon lower gear which was cracked as well from the stress of the worm gear being cracked? Any reason why that one cracked?

Posted by Maurice Leakey (Member # 916) on September 10, 2019, 04:46 AM:

An eBay sale of a one piece worm:-
https://www.ebay.com/itm/Bell-Howell-worm-gear-16mm-projector-500-to-2500-mod-/2326 76112391

Posted by Jim Schrader (Member # 9) on September 10, 2019, 12:52 PM:

Does anybody have a 2580 handy there is a small spring that popped off when I removed the main head and have a feeling it might go in this area?

And the spring looks like this-

Posted by Simon McConway (Member # 219) on September 10, 2019, 05:08 PM:

This spring keeps one of the sprocket guards shut.

Posted by Jim Schrader (Member # 9) on September 10, 2019, 05:12 PM:

Simon can you show a picture of where this would go? Thanks

Posted by David Michael Leugers (Member # 166) on September 10, 2019, 06:39 PM:

Maurice, thanks for the pic. I think I saw that before but thought it was an aluminum hub because in the pic the threads and through-hole look to me like aluminum. I wonder if there is any dimensional stability issues with making a one piece worm gear out of plastic like Delrin. It seems like Delrin would be so easy to make it out of instead of going to the trouble of making an aluminum hub, attaching a plastic sleeve over it with the threads...

Posted by Paul Repar (Member # 593) on September 12, 2019, 01:31 PM:

In response to all the claims of Bell&Howell and their original worm gears are ideas and opinions,their same lubrication was being used all inside their machines,the aluminum hub with the nylon over it known as the worm gear in my opinion cracked because of heat buildup causing the aluminum to expand and contract,which aluminum does in general when heated.But it could also been the constant use in the school systems as well,just an opinion,in response to Dave,Urbanski Film first original design was Derlin over an aluminum hub,nothing wrong with them,replaced about 25 machines using that particular worm gear,he has now since switched to aircraft aluminium,which is great,will never have an issue again.I have currently replaced about 40 of the new aluminum worm gears,and with the proper adjustments the machine runs super quiet.As far as that spring foes,Sam is right,seems to be a guard spring for a sprocket,if it came out of the lamphouse not sure why it would be there.Any help needed you can watch my worm gear tutorial on a 1500 series via this link.

https://www.youtube.com/watch?v=sVCs17tXDNs&t=7s

Posted by Jim Schrader (Member # 9) on September 12, 2019, 09:16 PM:

Thanks for that link paul I was watching this and gave me the idea to try it I got it in and the machine runs nice and smooth however my timing must be off I did as you mentioned the claw looked like it was pulling the film however when I loaded it with a countdown leader and tried it it just slid right by the gate.
Oh and by the way the spring I mentioned this is on the upper guide lock this is on there already is there another one? both guides seem to lock into place.

Posted by Paul Repar (Member # 593) on September 13, 2019, 04:48 PM:

Jim,The reason for the film just "sliding"thru the gate means the 3 claw protrusion needs to be adjusted.There is a small set screw which is located on the "in and out bracket"where the shuttle arms go thru and the 3 claw is attached to.If you aligned the shuttle arms with the claw on the downstroke,where the center tooth of the 3 claw is aligned to the center of the gate opening,you will need to turn that set screw slightly counter clockwise so that the claw protrudes a little more thru the slot,after you do this,and you will have to take the chassis out to do this,get a scrap piece of countdown leader thread it up like your running a film,close the lens carrier,and proceed to turn the belt pulley wheel while looking thru the lens carrier without the lens inserted.You will look and see if the countdown frames are aligned,and you also may have to adjust the framer knob as well.if you here any clicking that will be the look restorer tripping causing the film to want to pull perforations,means you will have to do more adjustments,if the look restore does not trip,then you are well on your way to have the timing set.Hope this helps!

Posted by Jim Schrader (Member # 9) on September 14, 2019, 10:03 AM:

Paul the adjusting screw you mentioned is this the adjusting screw circled in red I got the middle claw aligned with the center of the gate but how does one get in there to adjust it it looks unreachable. is this done after I get the chasis out?

[ September 16, 2019, 01:36 PM: Message edited by: Jim Schrader ]

Posted by Barry Fritz (Member # 1865) on September 19, 2019, 06:10 PM:

Jim. Paul said you have to take the chassis out to adjust the screw.

Posted by Paul Repar (Member # 593) on September 20, 2019, 08:32 AM:

Jim,Exactly how you have it in the photo,the little notch out above the hole in your photo on the shutter blade,there is likely a fire shroud covering easier access to that adjustment screw,if you remove that,you will have access using the bristol spline blade to make the adjustment,there is photos of this procedure on "how to" in some of the B&H service manuals,but yes you can do it with the chassis in or chassis out,its trial and error sometimes.

Posted by Jim Schrader (Member # 9) on September 22, 2019, 08:20 PM:

Paul, I took out the chassis to do the adjustments I lined up the claw on the downward stroke and adjusted the claw so it poked through the gate more but I cannot get it to sync up very well, on the upstroke seems to grab the film and push it up so I backed off the set screw now it doesn’t seem to grab the sprockets I tried adjusting the framer too but no luck.

Posted by Paul Repar (Member # 593) on September 23, 2019, 07:52 PM:

Jim,I think you may have over compensated that adjustment too much,It will take a few tries to adjust the 3 claw,that adjustment needs to be turned slightly to get the claw just right to grab the perfs,so try to go back where you started and give it a slight turn.Its best to use the service manual to get the right height of the 3 claw in the channel of the gate.Invest in a multi feeler gauge to measure the clearance.After this use your countdown leader and check the frame alignment by turning your pulley wheel,if it pulls the perfs by tripping the loop restorer your timing is still off.It will take a few tries but you will get it.

Posted by Jim Schrader (Member # 9) on September 28, 2019, 10:11 AM:

Paul I noticed you measured something at .015 was that for the loop restorer? what am I measuring I do already have one of these as I use them to measure points in my distributor on my old car. also i have heard one can use a Bell & Howell tool part number S-552-1-N1 would this be necessary to have? thanks f or all your input and help so far.

Posted by Paul Repar (Member # 593) on September 29, 2019, 06:15 AM:

Jim,Measuring the loop restorer "L" bracket distance of .015 spacing between the bracket end and the loop restorer cam that is on the right side of the worm gear.The feeler gauge helps in the spacing which is critical,if spacing is not proper,the "L" bracket will clip the loop restorer cam causing you to lose the film loop,which means this needs to be adjusted,if you download a service manual this will be explained in depth.

Posted by Richard C Patchett (Member # 974) on September 29, 2019, 09:41 AM:

Greetings Jim
If you do happen to replace the worm
Be sure that you also replace the
015533 Lower Sprocket Gear 1575/1580/2580
This gear usually cracks over time
You can tell if the film bunches up, just before the sound drum. with or without a new worm
save time and replace it
RC
Thanks Maurice for the referral

Posted by Maurice Leakey (Member # 916) on September 29, 2019, 11:04 AM:

Richard's comments remind me what my engineer said some time ago. I have two Bell & Howell Slot-Loaders, a 1680B and a 1680G.

He said that the internal mechanism differs between the auto-thread models and the slot-loaders. In the former, the worm drives direct to the two gears, each connecting to the two sprockets. Whereas in the slot-loader, the spacing is different, hence the need for an extra small gear. When changing a worm he always changes this small gear.

I assume that this is what Richard is referring to.

Posted by Jim Schrader (Member # 9) on September 29, 2019, 01:14 PM:

Ok I did order that as well and reinstalled the chassis and ran the unit that’s when I discovered the claw was not in time It ran real smooth other wise just gotta get the timing in place, thanks

[ September 29, 2019, 09:11 PM: Message edited by: Jim Schrader ]

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