Speed Run Bolex problems / help a bolex novice

[Miguel Mayans]

Good morning, everyone,

I just bought a second hand bolex and am checking it out. Being my first time with it and knowing the basics I have encountered a slight problem that I do not know if it is normal. When I wind it up and the movie starts running, everything goes fine but at some point it starts to lose power and starts to jerk. Is this normal or should it always go at the same speed until the string runs out? 

If it has a problem, do you know where to take it for repair?

Thank you very much!

M.

Edited May 12, 2023 by Miguel Mayans

[Miguel Mayans]

I imagine this must be a serious problem, right? 

Thank you for everything and I hope to help me about this things.

M. 

[Dom Jaeger]

No that’s not normal, and the scratching is bad.
What model is it (serial number)?

Are you sure you loaded the film properly? You can leave the lid off and run some dummy film through to check that the loop stays centred between the loop formers. Try to see where the scratches come from. 
It’s a good idea to find an original Bolex manual for the model you have online, there are quite a few around for free.

But a service is a good idea anyway.

In Europe you can contact Simon Wyss in Switzerland:

https://www.filmmechaniksimonwyss.biz/english/

or Guido Wilhelm in Italy at wtv@fastwebnet.it

There may be others who people can recommend.

[Jon O'Brien]

Is that an old piece of processed film ie. not fresh film? It looks dusty, and seems not very flat but it's hard to interpret what I'm seeing. I wonder if at least part of the problem is that the film has a slight curl in it from edge to edge. Is that a very serious scratch down the RHS or is that a strip of light glinting off the strip of film? To me something just doesn't look right with the bit of film.

[Miguel Mayans]

Hello again!

I was able to find the problem finally. On the one hand the film was scratched because the former owner had loaded the wrong side film and I tested with that film loaded. I noticed it and tested it correctly and it seems that the film comes out fine. No scratches at all.

I think the best thing to do would be to have it checked to rule out future problems or those that I don't see now due to my lack of experience with these cameras.

Thanks to both of you for the advice and I will get in touch with those contacts.

Best,

M.

[Miguel Mayans]

Hello again guys,

Just now I've done a test again on the speed at which the movie moves. At 24fps and it turns out that when the movie is not loaded (just with the mechanism released) it runs great and well maintaining the speed.

When I put loaded film, it seems to be difficult. As if the collection of the film was wrong. Maybe the drag system is affected?

Best

M.

[Doug Palmer]

10 minutes ago, Miguel Mayans said:

Hello again guys,

Just now I've done a test again on the speed at which the movie moves. At 24fps and it turns out that when the movie is not loaded (just with the mechanism released) it runs great and well maintaining the speed.

When I put loaded film, it seems to be difficult. As if the collection of the film was wrong. Maybe the drag system is affected?

Best

M.

Old Bolex's often lose speed during the run. So maybe the friction against the spools is not helping.  If the film appears steady either side of the gate it's probably not a transport issue.  Only a technician will know if proper lubrication is the answer.  Before sending the camera off, it's probably worth doing a film test with some old b/w film, to be sure it's nothing too serious and expensive.  Camera mounted seurely, say attached to a table or windowsill. Then do two superimposed passes on some newsprint, the second pass aimed slightly differently.

[Miguel Mayans]

Hi Doug,

Thank you for your advice about this. The problem appears towards the end when it takes about 20 seconds at a good pace and suddenly starts to slow down. At first glance I see that everything is fine but perhaps the lubrication is super important and as it has not been used in decades....

Sorry but I don't understand that kind of testing procedure.

[Dom Jaeger]

5 hours ago, Miguel Mayans said:

At 24fps and it turns out that when the movie is not loaded (just with the mechanism released) it runs great and well maintaining the speed.

When I put loaded film, it seems to be difficult. As if the collection of the film was wrong. Maybe the drag system is affected?

OK, that’s great, the camera seems to be running pretty normally. They all slow down a little at the end, particularly when under a load (ie transporting film), but a camera that hasn’t been lubricated in years will slow down more. The lack of lubrication will also cause wear to the bearings, which over time creates more drag. So a service is needed. If there is already a lot of wear, or the spring motor itself is tired, a service may not improve it much, but usually they come good.

When the camera runs with film, there is a load added from both the claw pushing the film, and the take-up spindle slipping as it winds on the film. You  can simulate the load by holding the take-up spindle and stopping it turning as the camera runs. A good, serviced camera should maintain speed when you add this load, up until maybe the last 5-10 seconds of the spring duration, when it might start to slow a bit. 

[Robert Hart]

If there is extreme governor hunt (jerking) and flashing of highlights during slow pans (lesser surges of speed), chances may be that oil has got onto the little leather governor shoes and may even have become gelled. Their normal operating state is to be completely dry. As the spring winds down and its power diminishes, the normally fine adjustments by the governor may have become coarsened by contaminated shoes momentarily gripping in the bell then being suddenly released as the centrifugal force collapses. The only cure is servicing by a proper camera tech. However please take heed of folk properly knowledged about the Bolex gizzards than I am. 

[Doug Palmer]

13 hours ago, Miguel Mayans said:

Hi Doug,

Thank you for your advice about this. The problem appears towards the end when it takes about 20 seconds at a good pace and suddenly starts to slow down. At first glance I see that everything is fine but perhaps the lubrication is super important and as it has not been used in decades....

Sorry but I don't understand that kind of testing procedure.

Certainly appears as if oil or lack of it, is a problem as Dom and Robert indicate.   I have an H16 that also slows, but otherwise OK for fairly short takes.  Also steady. That was really the point I was making earlier. It may be worth doing this steadiness test first, to see what the results are like.

[Miguel Mayans]

First of all thank you for all the help provided. Thank you in advance. I have been able to do a third more in depth check timing everything and when is the moment where it starts to slow down.

The first 20 seconds everything works perfectly but then it starts to slow down to the point where it is very hard and so instead of stopping at the 30 seconds continues until 35 seconds with a very heavy advance almost like a car idle when it starts to fail.

Maybe the camera is fine but need an overhaul with an expert of that kind of 16mm cams.

 

[Guido Wilhelm]

On 5/13/2023 at 5:00 AM, Dom Jaeger said:

No that’s not normal, and the scratching is bad.
What model is it (serial number)?

Are you sure you loaded the film properly? You can leave the lid off and run some dummy film through to check that the loop stays centred between the loop formers. Try to see where the scratches come from. 
It’s a good idea to find an original Bolex manual for the model you have online, there are quite a few around for free.

But a service is a good idea anyway.

In Europe you can contact Simon Wyss in Switzerland:

https://www.filmmechaniksimonwyss.biz/english/

or Guido Wilhelm in Italy at wtv@fastwebnet.it

There may be others who people can recommend.

Hi all, I let you all know that my new e-mail address is   wtv.milan@gmail.com

I'll be happy to solve your Bolex problem from Milan.