Dual 120 or 127 Film Reel

thingiverse

Dual Film Reel ============== This project is based on the 16mm Film Developing Reel (https://www.thingiverse.com/thing:4252926), which enables developing three rolls of 16mm film in a single spiral in a standard Paterson tank. My own goals are different, though, so I made some changes.... This design enables developing two rolls of 120 or 127 film per reel. I provide variants for both Paterson and stainless steel tanks. The point, compared to more conventional reels, is to save time and chemistry when developing multiple rolls of film. Revision History ---------------- * v1.0 -- 2022/03/06; Initial release * v1.1 -- 2022/03/16; Improvements for Paterson tanks: * Added spacing tube to keep reel(s) submerged * Added center column to support rotary agitation or keep reel(s) submerged * Reduced height of Paterson cap to enable use of two 120 reels in Paterson's 3-reel (35mm) tank Printing This Reel ------------------ I recommend beginning by printing the `dual-reel-stainless-test.stl` or `dual-reel-paterson-test.stl` file, depending on which tank type you're using, along with a copy of the `dual-reel-stainless-cap.stl` or `dual-reel-paterson-cap.stl` file. The cap object is used atop a stack of reels to secure it in place, but it can be attached to the test object to test tolerances. All the interlocking pieces incorporate pins and grooves, enabling them to be fitted together. (The tabs beneath the pins restrict the motion of the top spool when it's in place, and limits how far the cap can be pushed onto the test piece when a spool is not fitted.) Push the pieces together and then twist to lock them in place. There's a detent near the end of the twist; when twisted all the way, it will take more force to unlock the pieces. If you have problems getting the pieces to fit together, you can adjust your slicer settings, or in an extreme case, modify the `dual-reel.scad` file. Increasing the `radialEase` variable should make the objects fit more easily, and decreasing it should make for a tighter fit. Two caps normally fit with a gap into which a top spool fits, so the next object to print should be the `dual-reel-stainless-top.stl` or `dual-reel-paterson-top.stl` file. You can then see how it fits between the two caps. It should rotate smoothly but not wiggle excessively up and down. Note that the top reel's grooves should fit toward the bottom reel's grooves; see the photos. If your build plate doesn't release objects easily, be very careful when removing this part; it's easily damaged. Next, print the `dual-reel-stainless-120-bottom.stl` or `dual-reel-paterson-120-bottom.stl` file (or their 127 equivalents). This is the largest part. You should be able to fit it in place of the bottom cap in your test stack. Check to see that you can load film in it using a test roll or a developed strip of film. If you have problems, you may need to adjust the `filmWidth` variable and print this part again. Several cap files exist for different purposes. The `dual-reel-stainless-cap.stl` and `dual-reel-paterson-cap.stl` files are short caps useful for 120 reels in stainless steel tanks or for any reel in a plastic tank. The `dual-reel-stainless-tall-cap.stl` file is useful if you want to use a stainless steel reel and the 127-format spool in a stainless steel tank designed for two 35mm reels. the `tall` cap is taller than the standard one, and will therefore keep the reel submerged in a stainless steel tank. (A caveat: This is sized to work in my stainless steel tanks. It might be improperly sized for yours. This issue is covered in more detail shortly.) If you use a Paterson tank, you may optionally print `dual-reel-paterson-spacer.stl` or `dual-reel-paterson-central-column.stl`. (Neither model is useful in a stainless steel tank.) The former is a simple hollow cylinder intended to be placed atop your reels in a Paterson tank to help keep them from riding up the column. The model as delivered in 10mm in height, which is almost certainly too small for most purposes; you should probably stretch it to whatever size is needed for your tank and reels. You can either re-build the model from the `.scad` file, changing the `spacerHeight` variable; or use your slicer to stretch the model as necessary. The central column model is a replacement for the standard Paterson central column, but it includes a locking pin at the bottom to which the bottom reel can be attached. This prevents the reel from riding up the central column, and also makes rotary agitation via the agitation rod more reliable, as described shortly. Attaching the central column to the reel in the dark may be difficult, though. Also, the print must be sized for your tank. The `dual-reel-paterson-central-column.stl` model is sized for a Paterson Super System 4 3-reel tank, which is the one I own. If you own another tank, you must measure your existing column, edit the `centerColumnHeight` variable to match that value, and re-build the model. Also, be sure to print this model in a completely opaque plastic, particularly if your reels are translucent. The reels are meant to be disassembled and re-assembled for cleaning. or to enable using a single top reel and cap with both 120 and 127 bottom reels. If you prefer, though, you can glue the top cap to the central column of the bottom reel for greater security. If you routinely use a heat gun to remove wisps of plastic from your model, be cautious with this project, and especially with the reels. The reels consist of relatively small pieces, so a heat gun can easily warp them. Using This Reel --------------- The reels are loaded much like Paterson or other plastic reels, from the outside in. The top spool rotates several degrees, but there is no ball bearing to grip film; instead, you must do this with your fingers. Alternatively, you may be able to shove a roll mostly or complely onto the reel without rotating the spiral. After loading one roll, you can load another from the opposite side. After loading the second roll, check to be sure the first one hasn't partially unspooled; if it has, re-spool it as necessary. Reels can be linked together atop one another. It's likely to be easier to do this before loading the reels, but this may make loading them a bit more awkward. (I've only used a single reel myself, so I can't comment on the best approach from experience.) You must take precautions to prevent the reel from floating up in the tank. For the reel sized for stainless steel tanks, as just noted, the tall cap can be used, at least if you're using the appropriately-sized tank. If you're using a taller tank, you may be able to adjust the `capHeight` variable to print a custom-sized cap. (Using the test piece as a cap when loading film and then attaching a cap may be helpful.) The reels intended for Paterson tanks don't grip the central column very strongly, so they're more likely to ride up the column than genuine Paterson reels. Place a standard Paterson reel atop the 3D-printed dual reel, if there's space in the tank, or use a custom-sized cap, a cut piece of PVC tubing, or the spacer object from this project (scaled appropriately for your needs) to prevent the reel from riding up. Because these reels don't grip the central column very tightly, they may not work well with rotary agitation via the agitation rod. If you prefer this agitation method, perhaps a rubber band or piece of tape at the top and/or bottom of the reel set can help secure the reel, but that's speculative. (I use inversion agitation myself.) Alternatively, you can use the central column model from this project to replace the one that came with your tank; however, the model I provide is matched to my Paterson Super System 4 3-reel tank. You may need to adjust the `centerColumnHeight` variable and re-build that object if your existing center column doesn't match mine. If you go this route, you'll need to lock the bottom reel to the 3D-printed central column, and lock each additional reel to the one below it in the stack. Modifying This Project ---------------------- The `dual-reel.scad` file is the OpenSCAD source file. You can adjust several variables to affect the `.stl` files: * The various `make` variables (`makeBase`, `makeTop`, etc.) define which object(s) to make; set them to `1` to make the named object. * The `doPaterson` variable, when set to `1`, sizes the reel for Paterson plastic tanks; when set to `0`, the reels will be sized for stainless steel tanks. * The `filmWidth` variable specifies the width of the film; set it to `46` for 127 film or `62` for 120 film. In theory, `35` will work for 35mm; however, the spiral is only long enough to support a rather short roll -- in probably about a 16-exposure roll, although I've not measured this precisely. * The `capHeight` variable sets the height of the cap that's built when `makeCap` is set to `1`, as described earlier. * The `spacerHeight` variable sets the height of the spacer cylinder for placement above the reels for use in a Paterson tank. * The `centerColumnHeight` variable adjusts the height of the optional center column for Paterson tanks, as described earlier. If you build this project, and especially the spirals, be aware that it's computationally intensive. For instance, on my computer, the bottom spiral takes about a minute to render. For some reason, some versions of PrusaSlicer (version 2.1.1; but not 2.4.0) have troubles with the bottom reel `.stl` files generated by OpenSCAD (versions 2018.04.19 and 2021.01, at least); it blocks up part of the central core. Repairing the `.stl` file in either ideaMaker or PrusaSlicer fixes the problem and enables PrusaSlicer to correctly slice the model. I'm including repaired `.stl` files in this project, but if you re-build the file and slice it with PrusaSlicer, you should be aware of this problem. Cura, CraftWare, and ideaMaker can all handle the original files generated by OpenSCAD without modification.