A film bulk loader for up to 30 meters of film.
Here's a link to Fusion 360 design in the cloud.
Here's a link to Makerworld page
This work is licensed under the Attribution-NonCommercial-ShareAlike 4.0 International license. This means that you are free to download and print it for your non-commercial use-cases. Any improvements and modifications have to credit the original work and have to be made available under the same license. This is to ensure that everyone can benefit from other people making the design better in the future. It does not allow commercial use.
If you print it and use it, let me know.
I designed the spooler to be somewhat easily printable and have a few features that make using it nice.
My goal was to make a bulk film loader that would allow an easy manipulation with the film cartridge. I wanted to have the space where the film canister goes as open and accessible as possible. The spooler achieves this by the film canister space being open from the front and top and mostly open from the sides (see an image). More details about how to operate the "door-mechanism" in the section on how to operate the spooler.
There are different film producers and they might use differently shaped and sized spools. The film canisters are also little bit different. The canister cores from different manufacturers (the little bit that you twist and roll the film around, or rather your camera does that) have small variations in diameters. This is why the spooler has those two bits interchangeable (see an image with the bits and without the bits).
These two interchangeable parts use magnets to keep them in place. It's quite useful to have the cartridge holder kept in place by magnets—you don't have to deal with it moving and getting misplaced when manipulating the film cartridge in the loading-space.
The interchangeable rod that holds the bulk spool has another feature. Because it spins together with the bulk roll of film, the film does not spin on the inside of the spooler and there should be no unnecessary friction. It is also designed to raise the bulk roll a little from the bottom of the spooler so that the film's edges don't touch the floor. This is hard to verify as I can not see inside the spooler with the film in it.
There are files for the spool rod that fits bulk cores from Foma. I don't have access to bulk rolls from Illford or Kodak. Anyone is free and encouraged to either submit the right dimension for other spools or design it and push it into the repository.
The lever used for twisting the film into the cartridge does not need to be held or pushed down for it to stay in place. This way you don't have to worry about accidentally exposing the inside of the loading space in the middle of the process. The key-shaped lever is held in place by friction inside the "door-mechanism". You can learn more about this in the section on operating the spooler. This makes using the key-shaped lever pretty comfortable.
The top of the lever has a hole for a hexagonal key for easier turning if you want it.
The lever is asymmetrical for two reasons. It allows to sort of "lock it" in place and be released only in one position. It also makes counting the turns a small bit easier.
When you get to the end of the bulk roll it is very easy to wind the end of the film all the way into the film cartridge without noticing. To prevent this, the spooler has a special feature in the center of the lid. There is a circular cavity made for a small magnetic ball bearing to go around. The rod that goes into the bulk roll (or rather the bulk roll goes onto it) has a cavity to fit a strong cylindrical magnet. The position of the magnet makes it so that when the rod spins, it moves the ball bearing. When you can see the ball moving (or hear it), you know there's still film attached to the core of the bulk roll. Once the ball stops going around, you know the bulk roll is done. This solution allows you to know when you run out and carefully gauge how many turns you want to make before opening the door compartment to "catch the end of the roll". This specific design works without compromising the bulk-roll compartment.
The spooler is designed in such a way that the magnets can be omited. You can give up those extra features and nothing will be missing, no holes that need to be filled in or anything. The magnets are completely optional.
I have published print profiles for users of Bambu printers. You can find them here.
Users of other printers have multiple options. They can either download the "raw" step files and print the parts either using my settings or their own settings should they decide to make adjustments.
I recommend printing it with a black filament for maximizing the light-sealing property of the tool.
I print each light-critical part with at least 5 layers for walls. This means that there are usually at least 10 layers between the outside and the inside of the light-sealed compartments. In my experience, this is enough to prevent light from seeping through.
If you need help with printing, you can open an issue and I will try to help.
The only somewhat tricky part is the lid of the spooler. The lid has a small "tunnel" cavity in the center for the ball-shaped magnet. It is designed so that the ball can not exit the cavity (so that you can't lose it). Because of that, it has to be inserted during the printing process. In short, you have to insert it before the 22nd layer of the lid is printed as that layer goes over the tunnel. (Here's an image of the 21st layer.) For obvious safety reasons, the "official instructions" are: pause the print shortly to make sure that your hands do not interfere with the printer head. The plate is magnetic so that will make it easier for the ball to stay where it should.
PRO TIP: I recommend having a larger magnet nearby in case you drop the ball in the wrong place so that you can quickly retrieve it.
The "floor" of the tunnel (from the ball's perspective) has to be as smooth as possible. For that reason, I have added a modifier and also changed the settings for the seam (so that it's not aligned as that would cause a narrowing in the tunnel at one spot and prevent the ball from moving freely). If there are any issues and the ball is not spinning freely once the lid is done printing, you might need to investigate what is going on.
One key part of the assembly is gluing enough felt in various places. This section will walk you through it and offer explanation of why the felt is important for both light sealing and correct function. Another key aspect is how the lid is attached to the body of the spooler. To take care of that, you will need some extra material and tools. Finally, all the modular parts as well as the "empty bulk" indicator use magnets. I, personally, use neodymium magnets.
The lid and the body are held together using 7 M3 heat inserts and screws. You will need to buy those. It seems possible to instead tape the lid and the body together with a black electrical tape. For that, you will need to print the alternative lid with no holes. It should not be necessary, but it's better to be safe than sorry. If you decide to use the heat inserts, you will need something to heat them with and push them into the body of the spooler.
So here's a list of things you will need:
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7 pieces of M3 heat insertable threads (I use the short version)
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7 pieces of M3x10 screws
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4 mm ball-shaped magnet
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2 pieces of 3 mm x 3 mm cylidrical magnet (diameter x height)
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8 mm x 10 mm cylidrical magnet (diameter x height)
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2 pieces of 5 mm x 1 mm cylidrical magnet (diameter x height)
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superglue
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some black felt (cca 1 mm thick)
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soldering iron/pen (for heating and inserting)
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M3 bit
You will need to use the soldering iron/pen to heat the insert and push it into the hole. I give it a moment to heat up before I start gently pusing. You should not need to fight the material and you should push gently and slowly to make sure the thread is in straight and not too deep.
PRO TIP: If you ever need to dispose of the spooler and would like to re-use the threads, you can prepare the correct screw and use the soldering pen to heat the insert and then quickly pull it out using the screw. It should take just a moment of heating and not a lot of force. You want to use just the right amount of heat so that the insert comes out clean without excess plastic. (You should be able to pull the thread out completely clean.)
There are a few different places where you should apply the felt.
You need to apply the felt into the narrow passage in the body of the spooler. This felt serves a light-sealing purpose so you want to cut it just right. I like to measure the right height (from the floor to the edge of the walls) and make it twice as long than what I need. I then fold it in half and insert it into the narrow passage between the two walls all without applying any glue. I make sure the felt is in place and nicely straightened out. Only then I apply a small amount of glue in a vertical line to attach the felt's end (each) to the wall. There is no need to apply the glue anywhere else beside the ends of the felt. This way you just apply the glue four times and push gently onto the felt and hold it for a couple of seconds.
The whole inside of the door needs to be covered in felt as well. I like to cut the height a little bit longer so that I can wrap the felt over the bottom edge of the door and glue it there too. It makes it a really nice to use (no edges). Again, I only apply the glue locally in small bits all around the edges of the felt. This felt serves two purposes. It fills in the gap between the sliding door and the body of the spooler. It also creates enough friction for the lever-part to fit snugly and stay in place. They disc of the lever is designed with the felt in mind, so you have to put it all the way up otherwise there's going to be a gap and it won't have enough friction to stay in place. Also, it just looks nice with the entire inside of the door padded with black felt.
Gluing in the magnets should be an easy job. They should fit nicely in the holes with not a lot of force necessary. It should also take just a tiny bit of glue per magnet/hole.
You should make sure to not over-push the magnets too deep in the hole. (The holes are a tiny bit larger to accomodate for the material expansion.) To maximize their effect, they should be touching when the modular part is in place.
PRO TIP: The holes for magnets have a little bit of extra room to account for the material expanding while printing. To compensate for the hole being a bit too deep I recommend applying the glue to the sides of the flat cylindrical magnets (the ones in the base) instead of the bottom flat side. It might also be a good idea to insert the flat magnet by attaching it magnetically to the already assembled corresponding modular part (using the modular part as a sort of an applicator).
This section will show you how to operate the spooler.
Loading the spooler with the film is mostly obvious.
- You have to bring it into a completely dark room or use a changing bag.
- Pull the film through the narrow light-trap corridor first and then put the spool onto the rod and secure it inside the circle-shaped hole so that it can spin freely.
- You might want to tighten the film a little bit just so that there's no unnecessary slack.
- Then you can put the lid onto the body of the spooler and secure it using the screws. You might want to take turns tightening all of them "at the same time" so that there's no unnecessary tension and it all fits together nicely. You want to make sure that the lid is touching the body of the spooler everywhere and there are no gaps. Then you can expose it to the light.
You should have enough space to work within the loading-space of the spooler. The part of the process before you actually start twisting the lever should be straightforward. Then, depending on your preference, you might want to use one of two possible ways to close the door and install the lever into the film canister's core.
5 A. When the canister is in place and the roll of film is connected to it, you need to slide the door in place so that the slots in the lever are aligned with the cartridge's core. The door needs to slide all the way down and the bottom of it needs to be aligned with the bottom of the spooler. You might need to turn the lever gently as you are pressing on it to align it correctly. You should be able to recognise that everything is in place, it all fits together nicely, no slack, no gaps, no misalignment.
5 B. Alternatively, you could first put in place the lever without the door. This way you can see that the alignment is right. After the lever is in place, you slide the sliding door over it. This requires the lever to be in the right position. The lever is asymmetrical so pay attention to that.
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You can start winding the film into the cartridge now. The number of turns is as usual: cca 30 turns for 36 frames but you need to make some slack for the leader and the exposed part of film. When I do cca 32 turns, I get enough film for 37-38 frames when loading the camera outside the dark room. (When loading the film in a dark room, you might get more frames depending on your camera.)
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When you are done winding, you can position the key so that the door can slide up. You can remove the door, but keep the lever in place. This is a good practice when the fit between the key and the cartridge core is a bit too snug (you'd pull out the cartridge out otherwise and you might not want to do that). Then you can carefully disconnect the lever and the film cartridge.
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Finally, you can cut the film and close the loading compartment again. I like to store the lever in an inverted position so that it takes less space (you slide the door in first and then you put the lever "head-down" into the key-hole).