AAB-104 Cambridge Style Bag PDF Template Tutorial

By Jon Mance — @handy_leather  |  Read Jon's maker story here.

Click here to get the pattern

Hello, these instructions will guide you through the process of making Babylon Leather’s Cambridge bag with a laser cutter. Laser leatherwork is very different from traditional leatherwork, with its own pros and cons. A big advantage compared to traditional methods is that the laser does all the cutting perfectly. A disadvantage is the large amount of preparation required. These instructions cover many of the safety precautions, materials, tools, preparation, finishing, laser bed size, build order, build techniques, and hardware you will need to be successful.

Safety Precautions

When laser cutting, ventilation and fire risk are important safety concerns. Always follow the laser manufacturer’s recommendations when cutting any material. Having a way to extinguish a fire on hand is recommended.

Important: Only veg tan leather can be laser cut. Chrome-tanned leather and faux leather will destroy your laser optics, and faux leather can release chlorine gas when cut. I also don’t recommend cutting veg tan leather with a lot of oils or waxes because of the fire risk.

Materials

• 10–12 sq ft leather, 4.5–5 oz

(I bought a double shoulder and made 2 bags with leftover leather.)

I recommend dark-colored leather and thread to avoid charred edges and holes leaving marks on the leather. If the thread is light, it will pick up char during stitching and look dirty.

• 50 meters of thread
• 2 saddle stitching needles
• Leather shears
• Transfer tape (wide)

Tools

(Depending on the finished product you want, all these tools might not be necessary.)

• Fine edge beveler
• Sandpaper
• Rubber roller
• Positioning needle
• Strap cutter (you will need this if your laser bed is too small)
• Laser bed pins/magnets (to hold the leather flat while cutting)

Preparation

Preparation is key when cutting leather with a laser.

The first thing to do when preparing a leather roll for laser cutting is to cut the leather to fit your laser bed with shears. You want to cut your leather slightly smaller than the laser bed because it will need to be fixed to the bed using pins or magnets.

After your leather is roughly cut to size, you will need to mask both sides with tape. This step is very important because the laser burns through the leather, and without tape the top grain will become unsightly and charred. When applying tape, it is important that it is applied evenly with no air bubbles to avoid char marks. Use a rubber roller to help with this process.

After taping both sides, you might need to flatten the leather to ensure a clean cut. I achieved this by leaving my taped leather under large flat weights overnight. This step might not be necessary.

Once you have flat, taped leather, you need to dial in your laser settings to achieve the optimal cut. If your laser is set too powerful, the leather will crack and char when cut. Some variables I change to achieve optimal cuts are laser speed, laser power, laser focus, and number of passes. This file cuts everything with the laser, so this step is very important to ensure dimensional accuracy.

The final step before cutting is to affix the leather to the laser bed with pins or magnets. I tape the leather while it is pinned to the bed to determine where I need additional pins. After all this preparation, your panels are ready to be cut out.

Finishing

This step is subjective depending on the result you want. You could leave the laser-cut edge as is. Personally, I don’t like the charred look of laser-cut edges. I sand and bevel all the edges to remove the char and give the final result a cleaner, more resilient edge.

Laser Size

This file requires a large laser bed. I use a laser made by Glowforge that has a 279 mm deep by 495 mm wide bed. The largest piece in the file is 502 mm by 70 mm and barely fits the Glowforge bed when cut diagonally.

Build Techniques

This bag requires riveting, saddle stitching, and box stitching.

Build Order

The build order is necessary to ensure all the pieces fit together properly and don’t interfere with each other. Before the big panels of the bag can be sewn to the main gusset, I suggest assembling the handle, small pocket, small gusset/big pocket, D-ring straps, and top flap first. It is much easier to attach these parts while the bag is flat.

The bag’s stitching holes only line up one way. I suggest trying different orientations to determine how the pieces line up, then marking the back side of the leather accordingly.

Strap, Pad, and Thumb Lock

The strap length depends on where you want the bag to sit while wearing it. The shoulder strap pad is constructed by first sewing part A with part B, with both top grain sides facing up. Next, part C is placed with the top grain side facing down, and the assembly of parts A and B is sewn to part C. The thumb lock assembly is shown in the pictures.

Main Bag

The small pocket is attached to the big panel with corresponding holes to make a pocket with no gusset. The other big panel is combined with the small gusset and big pocket to make a pocket with a gusset.

The handle uses the handle core glued in the middle, then wrapped in the handle wrap. The handle is then sewn onto the top flap. The straps are sewn to the top flap. The top flap is then sewn to the big panel with corresponding holes. The D-ring straps are riveted to the main gusset.

After all these parts are constructed, the two big panels are ready to be attached to the main gusset.

Hardware

• 2 × D-ring, 3/4 in
• 2 × roller buckle, 1 in
• 2 × metal keeper, 1 in
• 2 × mini swivel lever snap, 3/4 in
• 4 × foot stud
• 2 × thumb lock (small)
• 8+ rivets
• Handle core, approximately 15 mm diameter depending on leather thickness

Hardware link