Do I use Loctite?

Derek Lofgreen · Jul 7, 2022

To the camera repair experts here. I have a Pentax ME Super with a loose advance lever cover. The little "button" cover that screws down over the top of the lever keeps wanting to unscrew a little each time I advance the film with the lever. When I take a close look at it, the threaded post on the cover seems to have some sort of rubber cement ish stuff that I am assuming helped keep it screwed in. My question is what should I use to keep this thing screwed down. Do I use Loctite or something else to keep this from backing out every time I advance the film?

Thanks,
D.

4season · Jul 7, 2022

Derek Lofgreen said:
To the camera repair experts here. I have a Pentax ME Super with a loose advance lever cover. The little "button" cover that screws down over the top of the lever keeps wanting to unscrew a little each time I advance the film with the lever. When I take a close look at it, the threaded post on the cover seems to have some sort of rubber cement ish stuff that I am assuming helped keep it screwed in. My question is what should I use to keep this thing screwed down. Do I use Loctite or something else to keep this from backing out every time I advance the film?

I'd first check to ensure that the threads are not contaminated with lubricant, and if they are, simply cleaning them might be enough.

If a thread locking compound is needed, try a low-strength formula, and apply sparingly. In the case of a long screw, you might only need to wet the top-most millimeter or so, the idea being that if (when) the fastener needs to be removed again, only the first couple of turns will have added resistance.

AgX · Jul 7, 2022

To avoid confusion, "Loctite" may mean most different compounds. Over here likely people first think of cyanacrylare glue, a in first instance permanent fixing.

You though seemingly think of a thread locker, of which under the Loctite brand versions of different locking-strength are available.

Dan Daniel · Jul 7, 2022

Two other options- acrylic nail polish. And elmers glue. Both will 'lock' a bit. Both break away when need be. And both can be removed without much trouble, mainly just peeling and chipping as needed.

For Loctite or thread locker, you want light or medium strength. Loctite brand, it's the blue. For Permatex, I think it's the red? Red Loctite needs to be heated to 4-500 F to release, so read the packages.

Any chance that there is a washer missing? Maybe a spring washer (wavy or bent flat circular) to apply a light upward pressure on the disk, thereby keeping the threads under tension and friction. Loctite and brute force are not the only ways to keep threaded items in place.

Craig · Jul 7, 2022

I's start with something like nailpoilsh first. If you do use loctie, use the 222, purple. It's designed for fasteners under 1/4". Blue is too strong, small screws will shear off before the bond breaks

AgX · Jul 7, 2022

Dan Daniel said:
For Loctite or thread locker, you want light or medium strength. Loctite brand, it's the blue. For Permatex, I think it's the red? Red Loctite needs to be heated to 4-500 F to release, so read the packages.

Loctite low-torque is marked violet. (Medium blue and high red and green)

Sirius Glass · Jul 7, 2022

There are several levels of LockTight conveniently color coded. Be very careful in choosing since some of the stronger ones cannot be undone on camera equipment without damaging the camera since they were meant for automotive repairs.

AgX · Jul 7, 2022

Yes, in case of doubt one better makes a test at a screw&nut of same material and dimension. Consider the curing time of 24h.

In this case the OP has it about a very small thread diameter.

Derek Lofgreen · Jul 7, 2022

Thanks for the quick responses! okay, so I think Loctite is a little heavy handed. The original substance that was on the screw post reminds me of rubber cement. The suggestion of nail polish is a good one I think. I will probably go with that on the last few threads of the post so the whole thing isn't gummed up.

AgX · Jul 7, 2022

In your case, how would you access that covered thread to dissolve nail-varnish?

(Daniel advised it as it would break-off at sufficient torque. But he likely has it about locking just the head of a screw, which is not applicable here. Applying nail-varnish to a later unaccessible thread seems no good idea to me.)

Sirius Glass · Jul 7, 2022

AgX said:
In your case, how would you access that covered thread to dissolve nail-varnish?

(Daniel advised it as it would break-off at sufficient torque. But he likely has it about locking just the head of a screw, which is not applicable here. Applying nail-varnish to a later unaccessible thread seems no good idea to me.)

Acetone or nail polish remover.

AgX · Jul 7, 2022

Sirius, you did not answer the question.

Dan Daniel · Jul 7, 2022

AgX said:
In your case, how would you access that covered thread to dissolve nail-varnish?

(Daniel advised it as it would break-off at sufficient torque. But he likely has it about locking just the head of a screw, which is not applicable here. Applying nail-varnish to a later unaccessible thread seems no good idea to me.)

The nail polish I have used for this breaks away fairly easily. When I think of removal, I am thinking of either polish on the top of a head, not as a thred locker, or getting rid of the bit that comes out under the head as you screw down and displace. Since the OP's part is a largish disk, a small amount of whatever material used will not gush out the edges, or if so the part should be removed right away and everything cleaned up. Nail polish is similar to shellac or varnish as a thread lock.

AgX said:
Loctite low-torque is marked violet. (Medium blue and high red and green)

Thanks! I don't know if I have seen violet in local hardware stores.

Craig · Jul 7, 2022

Dan Daniel said:
Thanks! I don't know if I have seen violet in local hardware stores.

I never have, I go to industrial suppliers. The Loctitie number is 222.

Sirius Glass · Jul 7, 2022

Sirius Glass said:
Acetone or nail polish remover.

AgX said:
Sirius, you did not answer the question.

Let it soak in. Then try to turn the screw.

Patrick Robert James · Jul 7, 2022

I'd avoid Locktite on cameras. Maybe the weak stuff but I'd rather use nail polish. If the disk moves with the wind lever then just a touch of it on the edge before you finish screwing it down will do the trick. If the disk slips then you are probably missing something.

I have a parts ME around here I think. If you are missing something let me know. Be happy to send it your way.

flavio81 · Jul 7, 2022

Derek Lofgreen said:
To the camera repair experts here. I have a Pentax ME Super with a loose advance lever cover. The little "button" cover that screws down over the top of the lever keeps wanting to unscrew a little each time I advance the film with the lever. When I take a close look at it, the threaded post on the cover seems to have some sort of rubber cement ish stuff that I am assuming helped keep it screwed in. My question is what should I use to keep this thing screwed down. Do I use Loctite or something else to keep this from backing out every time I advance the film?

Thanks,
D.

Sounds like a missing washer. Probably the advance lever top screw is getting friction against the advance lever. This should not happen on an ME or ME Super.

Maybe it's better if you check a parts diagram and compare to your camera.

This is not going to be solved with loctite or the like. My ME cameras never needed any locking compound on the cap screw.

Derek Lofgreen · Jul 7, 2022

Not a missing washer or parts. I have owned this camera for 15 years and know the previous, original, owner. It has all its parts. There used to be a little dab of some sort of adhesive on the last couple of threads that has dried up and now the threads have let loose. The old adhesive looks like dried up rubber cement to me. I may give a little of that a try first instead of the nail polish or Loctite.

D.

j-dogg · Jul 8, 2022

I have an NKVD FED with an adjustment screw for the RF that would come loose after a few minutes of use so I used the violet Loctite and that worked fine. I was also able to break it with a screwdriver fairly easily but it would not vibrate off.

I did make the mistake of Permatex blue "medium strength" on the same job on my Leningrad and it's basically welded now, which is a good thing because the calibration is spot on across my lens range. If it comes down to it I can swap the assembly from my parts Leningrad

gone · Jul 8, 2022

You could use a tiny drop of nail polish on it. We used Loctite on race cars, that might be a wee bit of overkill on a camera.

AgX · Jul 8, 2022

Sirius Glass said:
Let it soak in. Then try to turn the screw.

You still not get my point....

Your approach will work under normal circumstances. In cases as here we got a tiny bolt with as head a large disc, and under this disc parts that must turn freely. The locking substance then would be hidden quite deep. You would have to kind of flood this part of the camera to reach it with solvent.
(The design of these mechanisms vary, and there migh be a stud with a female thread under that disc on which it rests, but still then getting solvent there is not evident, remains thus only the breaking off approach.)

monopix · Jul 8, 2022

AgX said:
In your case, how would you access that covered thread to dissolve nail-varnish?

(Daniel advised it as it would break-off at sufficient torque. But he likely has it about locking just the head of a screw, which is not applicable here. Applying nail-varnish to a later unaccessible thread seems no good idea to me.)

It's all down to quantity. If you slather the whole thread in nail varnish, don't expect to ever remove it. If you put a tiny drop on the top of the screw (the last part of the screw to enter the thread) it will break when you unscrew it. Nail varnish is brittle and will break (evidenced by my wife having to replace hers regularly). But I use Loctite Blue for such things. I use a pin head amount on the screw then wipe most of it off so there is just a little left in the thread. I wouldn't apply any more than that.

BrianShaw · Jul 8, 2022

My understanding for small screws that either adjust critical functions or may vibrate loose on small items like clocks, watches, cameras and test equipment… the traditional (best) way is a small dab of nail polish (or the like) on an edge of the HEAD where it meets its mating surface, not the threads.

Sirius Glass · Jul 8, 2022

AgX said:
You still not get my point....

Your approach will work under normal circumstances. In cases as here we got a tiny bolt with as head a large disc, and under this disc parts that must turn freely. The locking substance then would be hidden quite deep. You would have to kind of flood this part of the camera to reach it with solvent.
(The design of these mechanisms vary, and there migh be a stud with a female thread under that disc on which it rests, but still then getting solvent there is not evident, remains thus only the breaking off approach.)

Use a jack hammer or only use the smallest amount of the weakest type of Lok-Tite [purple?] or better yet have a real camera person work on you cameras. The last is my go to solution.

flavio81 · Jul 8, 2022

Derek Lofgreen said:
Not a missing washer or parts. I have owned this camera for 15 years and know the previous, original, owner. It has all its parts. There used to be a little dab of some sort of adhesive on the last couple of threads that has dried up and now the threads have let loose. The old adhesive looks like dried up rubber cement to me. I may give a little of that a try first instead of the nail polish or Loctite.

D.

Ok, sounds good. I also don't remember any washer, but coudn't have any other explanation.

This is the parts diagram (from the ME which should be identical). What I recall is that the retainer C8 is the most important part to get tightly locked. If you get it sufficiently tight then C139 (cap) should not unscrew.

Do I use Loctite?

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