How to Cut (leather) Corners

1. Copy the template from the sketch (1 cm squares) (Photo 1). For a single corner, you can use thick paper or cardboard; if you want make more, a piece of thin aluminium or zinc is better.
   
   
   
   Photo 1. Template.
   
   
2. Make a mould from a piece of (hard) wood, thick 23 mm and 65 mm wide; slightly round the corners. Drill 3.1 mm holes as can be seen on the pictures, corresponding with the holes in the steel reinforcing corners. Also make at least 4 steel pins fitting the holes; 3 mm welding rod will do. (Photo 2)
   
   
   
   Photo 2. Hardwood mold.
   
   
3. Find some saddle leather, 2 - 3 mm thick; black or brown will do. Be careful with old leather from briefcases etc..; it will easily tear or break.
4. Cut the leather according to the template; there is a difference between the left and the right corner ones! Punch out the 4 holes with a 3 mm hollow punch. (Photo 3)
   
   
   
   Photo 3. Cut and punch leather pieces.
   
   
5. Soak the leather for 24 hrs in water.
6. Insert two pins in the mould, put the leather on these pins, and fold around the mould. Then, insert the two other pins. With 3 mm leather this will require some persuasion! (See photo 2).
7. Let the leather dry for 24 hrs; do NOT use heat.
8. Now put the corner in place, temporarily fixing it with 3 mm screws and with the steel reinforcing corners in place. (Photos 5 and 6). If you don't have these corners, you will have to make them of thin (0.8 - 1 mm) sheet steel, and treat them with any anti-rust product; I used zinc coating from a rattle can. (Photo 10)
   
   
   
   Photo 10.
   
   
9. Put the bag on the frame, and mark the place of the press fastener using a small hammer. (Photo 7). Remove the corner, and put in a press fastener; if you don't have the tools for that, go and see your friendly shoemaker.
   
   
   
   Photo 7.
   
   
10. Attach the corner again with the 3 mm screws, and using 3mm flat head copper rivets and washers, replace one by one the 3 mm screws (photo 8).
    
    
    
    Photo 8.
    
    

    If the rivets are too long, cut them off at about 2 mm above the washer. Avoid the normal hollow rivets; they will not withstand the rough life on a M20 bike, unless they are of the stainless steel variety (photo 9).

    
    
    
    
    Photo 9. Rivets.
    
    
11. Use a split rivet to fix the small corner flap.
12. Now finish with some leather oil or wax.