Bell and Howell 70DR / filmo spring motor lubrication

Don Arntz · July 28, 2019

Hi,

I'm just starting to clean up and lubricate an old bell and howell 70DR. The regular lubricant points are obvious, but is there grease in the compression spring / winding key area? If so, can I open that area up to lubricate without spring danger (as in putting in grease without trying to remove the spring)?

Thanks for any help.

Simon Wyss · July 29, 2019

Yes, the winding key should be lightly greased in the spring core. A snap ring should be lubricated. The gear train gets oil through a felt wick sitting at the bottom of the spring core. The main spring is lubricated with graphite powder. You cannot refresh the graphite without a complete disassembly. Better leave the bigger jobs to a tech.

Don Arntz · July 29, 2019

Really? I'm pretty handy at fixing film cameras. There is no way to sneak some graphite into the spring without removing the spring? (I'm at work at the moment, so I can't examine it). If not, can I assume it is still properly "lubricated" if the graphite doesn't really leak out and (unlike grease) will not harden and gum up?

Philip Forrest · July 29, 2019

I don't want to step on anyone's toes since I'm the new guy but I take everything I own apart and rebuild just as a hobby (and as what we call self-care in my profession of mental health worker.) So here are my personal tips and observtions regarding these amazing cameras, much of which I'm repeating from other places on this forum.

If you have old grease that has dried into a hard mass, it will have to be removed. I'd stay out of the main spring and clockwork because you may slice your body up when that spring unloads.The deepest maintenance you shoud get into is as folows:

Let the camera completely wind down. Remove the turret plate and make sure to catch the two or three small pawls that are located around the edge of the chassis and give the turret its notches for lens/lock position. Save the tiny washer that should be under the turret. Unscrew the 4 screws holding the front plate in. Gently remove it while keeping your finger over the shutter release. Here is where it may get difficult because the front plate is steel and the chassis is aluminum, so some galvanic corrosion may have occurred and welded them together over the last 60 years. Once you get that free, you can dunk it in the solvent of your choice if it needs it. Over th last two years, I have restored 5 of these cameras an only one needed the shutter mechanism really cleaned, that was a 70DA. My DR and DL were and are immaculate inside although the outsides show a bit of wear. If you use a solvent on the shutter, make sure it is completely dry then begin dabbing lubeon the moving parts. If you see the lube, you've added too much. Stick the shutter mechanism back in the chassis while negotiating that shutter button and spring that you madure sure didn't fly out when you took it apart. Getting it back in can be a pain but it can be done. Put the little spring loaded pawls be in the chassis then stick the turret plate back on gently and work the awls in one at a time. Screw on the center nut, take out the little cap, add a drop of really high quality oil (I like to use a synthetic oil used for watch repair because it will not polymerize). There is a tiny weep hole near the hole for the manual crank/motor. Add a drop or two there to soak the pad that is inside that housing. Wind it up and go.

Phil Forrest

Simon Wyss · July 30, 2019

There spook false statements through the web. One of them is that movie camera drive springs had sharp edges. That’s nonsense, they have nicely ground round edges. It must be ruled out that the convolutions hook onto another by burrs or sharp ridges.

Nonetheless the sudden unleashing of the stored energy can be dangerous. A pair of leather gloves and calm nerves are all it takes to handle main springs. Plus some force

Webster Colcord · July 30, 2019

I can't speak to the sharpness/danger of the spring metal itself but I once had an Eyemo spring break on me (in the camera) while I was winding. The winding key suddenly snapped back, hit and jammed my thumb really hard. Sore for weeks!