Metalic Reel Loader - 35 mm Developing Aid

35 mm Film Loading Aid for Stainless Steel Developing Reels

Loading 35 mm film onto stainless steel developing reels can be a frustrating task, especially when working inside a changing bag or in complete darkness. This device was designed to minimise the operations that must be carried out in the dark, allowing the film cassette and reel assembly to be prepared beforehand in normal light.

The device consists of a main frame with an integrated side arm and a removable arm. The film cassette is mounted at one end and the stainless steel developing reel at the other.

To allow smooth rotation of the reel, two coupling hubs are used. These fit into the centre of the reel, one on each side, and rotate freely within the support arms.

The device also incorporates a film curvature and alignment guide, which maintains the film in the proper curvature and alignment relative to the reel entrance, facilitating engagement with the correct track during loading.

The device does not require any modification to either the reel or the film cassette, functioning solely as an external loading aid.

Bill of Materials

In addition to the printed parts, the following hardware is required:

• 2 × 3 × 12 mm self-tapping wood screws;

• 1 × M3 × 25 mm hex-head screw;

• 1 × M3 heat-set threaded insert, 5 mm outside diameter and 4 mm length.

Optional

• 1 × 3 × 15 mm self-tapping wood screw for assembly of the rewind crank.

Device Assembly

Before first use, assemble the device as follows:

1. Install the M3 heat-set threaded insert into the designated recess in the main frame.

2. Assemble the locking screw into its respective knob.

3. After fitting the locking screw into the knob, press the finishing cap into its recess. The cap is designed as an interference fit and may require moderate force to seat fully. A wooden mallet or another non-metallic tool may be used to assist assembly. Under normal circumstances, adhesive is not required.

4. Attach the film curvature and alignment guide to the main frame using the two 3 × 12 mm self-tapping screws.

   The film curvature and alignment guide is a separate component, allowing replacement or future design updates without reprinting the entire device.

5. If desired, assemble the optional rewind crank using the 3 × 15 mm self-tapping screw.

   Tighten the screw until the head contacts the crank, then back it off slightly to allow free rotation. The objective is to eliminate excessive play without restricting movement.

Once assembled, the device is ready for use and should not normally require further disassembly.

Preparing the Film

After removing the film leader, prepare the assembly as follows:

1. Insert the film cassette into its designated slot in the main frame.

2. Position the developing reel fitted with both coupling hubs.

3. Fit the removable arm, ensuring correct positioning of both the film cassette and the coupling hub on that side.

4. Secure the arm using the locking screw.

5. Curve the film end through the film curvature and alignment guide and feed it forward until it is secured by the reel's retaining clip.

At this stage, the entire assembly is ready to be placed into a changing bag or other light-tight working environment.

Loading the Film

Holding the frame, slowly rotate the reel while keeping the cassette film exit as closely aligned as possible with the reel entrance.

Once the film has entered the correct track, continue rotating the reel until the entire film has been loaded.

When loading is complete, cut the film at the exit of the film curvature and alignment guide using scissors.

Removing the Loaded Reel

Once the film has been fully loaded, loosen the locking knob and remove the detachable arm.

The developing reel can then be removed together with the loaded film. The coupling hubs are not permanently attached to the reel and will separate naturally during disassembly.

This behaviour is intentional and allows the hubs to be reused immediately when loading the next film.

Using the Device Without the Film Curvature and Alignment Guide

Use of the film curvature and alignment guide is recommended, as it assists initial engagement of the film into the correct reel track.

However, the device may also be used without this component. In that case, the operator must manually establish the required film curvature and alignment while securing the film to the reel's retaining clip.

The removable design of the guide allows each user to adapt the device to personal preference and working practices.

Optional Rewind Crank

The project also includes a small optional crank for rewinding the film into the cassette.

Although normally unnecessary during loading, it allows the film to be rewound completely into the cassette should it be desirable to restart the operation for any reason.

The device is intentionally designed to allow free rotation of the cassette during film loading, helping maintain natural alignment between the film and the reel. During rewinding, however, cassette rotation relative to the frame must be prevented. Otherwise, the cassette and frame will rotate together and the film will not be rewound.

The crank may also be useful for other operations involving reusable 35 mm film cassettes.

Note for Bulk Film Users

The recommended cutting position leaves an appropriate length of film inside the cassette for future reloading when using bulk film. This allows the cassette to be reused without additional preparation.

Compatibility

The device was designed for standard 35 mm film cassettes and stainless steel developing reels. As small dimensional variations exist between manufacturers, a preliminary fit test is recommended before use in darkness.