So, I wanted a coarser file, but I didn't want to go buy one. What I came up with is a home made file that works very well for me.
Items required:
1 Pair of Chopsticks or Plastic Rod
1 Sheet of Sandpaper (grit to your taste)
1 Superglue (or other, if you prefer)
1 Hobby Knife
1 Saw (Optional)
Step 1:
Cut the chopstick to remove the square end.
Step 2:
Apply glue to one side of the chopstick. Only apply along the section of chopstick you will apply the sandpaper to.
Step 3:
Once glue is applied, roll the sandpaper onto the chopstick so that all the glue is covered. Hold for a couple of minutes to allow the glue to set.
Step 4:
Using your hobby knife, cut away excess sandpaper. I cut along the chopstick itself, as this insured that all of the sandpaper was glued.
Step 5:
Apply glue to the remaining uncovered chopstick. Again, hold for a few minutes to allow to dry.
Step 6:
Cut excess sandpaper away.
Viola, home made file.
If you were to use a square chopstick, rather than a round chopstick, you could apply different grits of sandpaper to each side, allowing multiple grades of filing to be done with a single tool.
If you use plastic rod, you can use a smaller rod for harder to reach areas. Note that coarser sandpaper tends to be thicker, so it is more likely to crease and less useful for smaller diameter rods.
I hope this helps you in your projects!