Mole Richardson 410 Mechanism

southernclub

New Member
Hello. I'm trying to fix a Mole 410 with a frozen lamp mechanism. It's the part that moves the lamp and there are two parts I don't know how to fix. In the picture with the red arrow, what is that dot called? I think it's what held the part it goes through to that rod but the rod turns free now. I'm guessing it needs to be drilled out but I don't know what it's even called to try to replace.

The part that's frozen has the large screw sticking out the top. There was a nut holding a spring on the screw that came off easy enough but I don't see how to disassemble that part any further. It's is riveted in so it doesn't seem like it's supposed to be modified from the bottom.

Any help is much appreciated, thanks.
 

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From my memory (of something like 50+ years ago) here's my thought: The lamp focuses by turning the knob on the back of the instrument--about a half-turn as I remember. The focus knob rotates the focus shaft which runs from the back to the front. The red arrow points to a pin which pins the crank (immediately below the pin in the photo) to the rod. That crank pushes or pulls an adjustable rod (just barely visible in photos #1 and #2) which rotates the large round aluminum part with the big screw (seen side view in photo #3 and top view in photo #4.) The crank arm extending from the large round aluminum piece ("above" it in photo #4) pushes or pulls an adjustable rod (shown in photo #4) which attaches to the lamp socket & reflector carraige. The result of this is that, due to the distance multiplication of the cranks & adjustile rods, about a half-turn of the focus knob on the back of the instrument moves the lamp socket carraige the full distance from flood to spot.

Clean & polish up the 2 rods running front-to-back in the instrument which the lamp/reflector carraige slides on and lube w/graphite. or hi-temp grease Clean up everythig & lube w/graphite or hi-temp grease.

Love these M-R instruments, all the way from babies to 10s! Let me know how yours turns out.

An afterthought: The pin (red arrow) probably sheared off when the focus knob was turned because of too much friction in the mechanism--dirt, rust, etc. When cleaned up everything will work smooth as glass.
 
Hello. I'm trying to fix a Mole 410 with a frozen lamp mechanism. It's the part that moves the lamp and there are two parts I don't know how to fix. In the picture with the red arrow, what is that dot called? I think it's what held the part it goes through to that rod but the rod turns free now. I'm guessing it needs to be drilled out but I don't know what it's even called to try to replace.

The part that's frozen has the large screw sticking out the top. There was a nut holding a spring on the screw that came off easy enough but I don't see how to disassemble that part any further. It's is riveted in so it doesn't seem like it's supposed to be modified from the bottom.

Any help is much appreciated, thanks.
Calling @ship Can you help this new poster?
Toodleoo!
Ron Hebbard
 
John's accessment is about what I would in all ways. I will if time tomorrow review the fixture, but doubt I will find anything better than reccommended. Appairently focus screw resistance or broken pin part.

Change that... if a part of the fixture is not working properly... also recommend to check the lamp and lamp base for arching... What is causing the problem is also a call to inspect the fixture for repairs. Just as if you find one side of a cable badly done or with a problem... the other side of the cable should be suspect. Recommended is if a problem, ensure other parts of the fixture is not of a problem.... That and the rest of the fixtures for maintinence service call.
 
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Hello all. Thank you for the quick replies! As Jon Carter stated, that is how the mechanism works and it does look like the pin with the red arrow has sheared off. Probably somebody tried to force the handle but the part with the big screw sticking up doesn't move at all. The lamp carriage is disconected so it's not affecting whether that part moves. I don't see how to disasseble the part with the screw any more than i already have. Does anybody know how to take that apart or what that pin that broke is called?
 
Well, the pin is just a shear pin. I suppose hat you could replace it with a standard roll pin which fits the hole snugly, although the shear pin may have been designed as the "weak link" which would break first in the event of the mechanism jamming, rather than some more expensive part breaking.

As to the big screw in the center, it appears to be seriously stuck1 Judging by the rust on the adjustable links, it would appear that this guy's been under water, or at least out in some serious rain! I'd try penetrating oil on the big screw and let it soak for a couple days. Then dry it off (blow dry w/compressed air) and GENTLY heat it with your propane torch. The idea is to expand the round aluminum part so that it will release from the steel bolt/shaft and move--any direction, rotate or lift. Then try another penetrating oil soak. All the pieces will come off--eventually. Keep track of the order in which they come off.

Back to the big screw in the center: Photo #4 shows a pin through the big screw, holding a piece below the top aluminum disk & crank to the big screw. Once the top aluminum disk & crank are off, you will have access to what's below. You may need to remove the pin. (Try tapping both ends; it may be tapered.)
 
Thank you Jon. I tried "Deep Creep" and let it soak for three days. If there's a better lubricant, let me know. The problem seems to be the black material in this picture It's rubbery and fused to the metal parts. I haven't tried heat yet but if that doesn't work was going to try to cut in the black stuff with a dremel enough to try to pry it apart. I'm not sure that's a good idea because I don't know what the black stuff is. Do you know if it's asbestos?
mole 5.jpg
 
I highly doubt that the black stuff you refer to is, or contains, asbestos. This material (your red arrow) seems to be between the bottom disc w/shaft to the crank on the control shaft, and to the top disk with the crank to the control shaft to the lamp carriage. (Hope that makes sense--if not please let me know & I'll try again.) It may be a "friction clutch" material between the two discs.

At any rate, the two large aluminum dicks WILL come off the large bolt somehow; after all, they went onto it once.

RE: friction clutch: Was/is there a pointer on the focus knob on the back of the instrument? Was/is there any sort of scale around the focus shaft that the pointer would point to? The focus knob moves the lamp back & forth, changing the beam size. (Which is usually what we need it to do for stage use.) In the process, the intensity of the beam changes quite a bit. When we used these instruments for film work, the "focus" knob is usually used as a dimmer to adjust instrument brightness, regardless of beam size. (The extents of the beam are usually out of the camera shot and are irrelevant.) A friction clutch between the knob & the lamp carriage would allow different "spot/flood" settings to be set to specific knob locations, permitting use to adjust brightness during a take.
 
Well, glad to see the memory isn't totally shot! Still trying to picture the inside of a Mole but it's been over 50 years.. Wasn't there a knob on the Big Screw? (MR-5) Tension adjust on the clutch?
 
I got a Mole stand for it in this week and took that to get sandblasted. I briefly tried a heat gun to loosen the black stuff. It got too hot to touch and started giving off a smell but didn't loosen. I won't be able to work on it again this weekend but maybe Monday I'll be able to try again. I'll next try a dremel but I also have half a mind to leave well enough alone with that mechanism.
 
Thanks for the info. I trust that you disassembled the M-R stand and are having the pieces sandblasted (and maybe powder-coated, too?) individually. There are a lot parts to one of those stands and painting it assembled leaves a lot of missed spots.

Now, you've got me going on this thing. As to the mechanism, I know that comes apart--somehow. Looking at your photo #4: there's a pin through the large screw..Have you tried to remove it? There may not be room with the upper aluminum disc in place, but give it a whirl. Where is the bottom/other end of the large screw? Have you tried turning it? With both of the lever arms (photo #4) removed will the upper aluminum disc rotate? Will it move at all? (Wiggle, anything?)

(Still thinking . . .)
 
Sorry, have not had time to review the fixture or keep up with progress. If sent to me I would bring it back to factory spec., but where would that be for fun for you.
Pin would be a set screw, normally of high carbon steel, and as rusted as the other parts are... this would be very difficult if not impossible to remove. At this point overall lots of "Liquid Wrench" over everything because everything will need to be resurfaced and cleaned anyway. At least a hope... New products out there that supposidly do better than Liquid Wrench, possibly worth a try.

Spray, wait and take everything apart. Take lots of photo's for re-assembly. On the question of the appairent set screw holding casting to rod.... if you can isolate this mechanism in taking everything else apart. If you can isolate this mechanism it might be possible to drill out or otherwise remove the rod from the casting. Than just a simple Dremmeling away what is left of the set screw and making a new set screw hole. Lots of rust, try not to sand blast everything, won't help some parts in better ways to remove and preserve.
 
Hi Jon and Ship.

The round plates with the lever arms and the big screw going through them doen't seem meant to be serviced fom the bottom. That whole part is riveted in with three brass rivets. I don't know what the pin running through the screw is for but it doesn't seem to be there to hold down the top plate. I don't think I can get it out without removing the top plate. The levers are disconnected and that assembly just doesn't budge. The plates move concentrically around the screw and they The problem seems to be the black stuff sandwiched in there. It has been soaked in a product called "Deep Creep." My guess is a similar product won't do any better to loosen it. Rust doesn't seem to be the problem. The base, middle, and, top plates are aluminum. I've attached some new pictures showing the spring and nut in place on the screw.

It seems to me when the spring came off the middle and top plates should have been able come off. The problem has got to be that the black stuff has glued everything together.
 

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I'm thinking the black material wasn't fused to the aluminum by heat. Maybe it was melted by a solvent. Perhaps someone triend to lubricate it with something incompatible with the black stuff, and then it dried glueing eveything together. If we knew what the black material was, then maybe we could determine what solvent would work to loosen it.
 
OK - that makes more sense now that I see the spring and nut on the top of the large screw. The device (bottom plate riveted to housing, middle plate/crank from control shaft, top plate/crank to lamp carriage pressed by spring AND FRICTION MATERIAL BETWEEN PLATES) is a means of adding friction to the forward-backward (flood-spot) movement of the lamp assembly. Without it the weight of the lamp assembly would cause it to slide on its rods from spot to flood as the instrument was tilted pointing up to pointing down. The large nut & spring is a friction adjustment, allowing the operator to adjust the friction to a point where movement of the focus knob was relatively easy while still holding the lamp assembly in the desired position. (Check me on this, Ship.)

Once the adjustment nut, spring and lever arms are removed the upper and middle discs should pull straight up and off of the large bolt. they appear to be stuck in the gooey mess of the friction materials between the discs. Try a wheel puller, or gently prying from opposite edges of the upper disc simultaneously with a pair of short screwdrivers, than same on middle disc.

Anxiously awaiting your report!
 
Sorry in not dong my homework, got busy in managemement of three new assistants and projects to get out the door. I have direct contacts with Mole, and lots of old catalogues that could help me, but while the parts are similar, I do not have one of these fixtures in experience with. Jon Carter's advice seems sensible as always.
Doesn't help on my part.
If you want to pay shipping to me and shipping back, I will fix if for free, and note for posting what I found and or how it was fixed. Parts would most likely be free if just normal parts including the lamp socket... and fixing back to factory spec. or better. You could also bring the fixture out to me in Northern Illinois - like 60 miles West of Chicago, and we could fix it together.
Otherwise keep reminding me if of help in having worked on quite a few Mole fixtures from 1936 Fresnel thru 10Kw. and indeed doing the work on the Mole fixture for the BatMan tour. Just two weeks ago converted MoleBeams into three NSP PAR 64 prop lights for a tour leaving in April. The focus mechanism, and other mechanisms is mostly the same for all. The Mole light I frequequently work on, mostly in converting to LED, smaller wattage, moving light inside it, or LED PAR of some type all for prop light usage for a tour.
Given that... I have a lot of experience in taking them apart in general. Not seeing the spring loaded nut central question at the moment for help, other than "heavy hex" I have seen before requiring that wrench you have never used before.
 
Ship, as you say the guts of a number of the M-R fresnels (baby, junior, senior, ets.) were pretty much the same. (The 412 is/was the 2kW "Junior" solar spot.) Although parts for the #412 mayno longer be available from M-R, a parts blow-up diagram would show how they're assembled and would give Soouthernclub an idea of how to get things apart & then re-assemble.
 

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