the .357 Sig (Pistol Cartridge) make a MOST EXCELLENT "Plug" style hole punch. The size is perfect for a standard binder ring.
There is a little trick that I use though, which greatly improves this type of cutter.
I made this at TechShop Menlo Park
Read on, if you are a paper pusher that happens to have access to spent cartidges :-)
Step 1: Find a .357 Sig Cartridge (spent!), Check It for Roundness and Condition
Find one that is nice and round; My sample is here is from a typical range round; it is a necked-down brass cartridge.
Step 2: Remove the Cap (totally OPTIONAL)
Stand off the cartridge from a hard flat surface by using a washer or machine nut which has a hole LARGER in diameter than the cap.
Find a very slim tool; a punch, a jewelers screwdriver, allen wrench, etc... Place it down the open end of the cartridge and into the little hole in the bottom.
Now, using a small hammer (or other suitable stand-in for one) tap the punch gently...the cap should pop right out.
Step 3: Grind, Cut, Lap the Cutting Edge
I made a quick little V-grove holder for the vise, from some scrap wood in the TechShop Woodshop.
Using a suitable tool, sharpen the INSIDE EDGE (Interior diameter) of the cartridge very carefully. I used a dremel tool with a very fine lapping tool installed. A small rats tail file or even a sharp knife, will work quite well.
Step 4: Braze a Handle Onto the Cartridge (OPTIONAL)
Using a very small brazing tip, preferably 000 (Triple "ought"), in my case it was double-ought, and using appropriate work hold mechanisms, place the handle on top of the cartridge and braze it on...Go easy, that is a LOT of heat and thin brass!
Do NOT forget to use flux when using the Oxy-Acetylene torch. The prep time, in this case, was several minutes....for a braze time of a few seconds :-)
When done, allow to cool and then head into the dirty room (grinders, chop-saws, sand blasting) to clean up the finished product!
Step 5: Clean Up and Repair, As Necessary
Aluminum melts easily.
Carefully use the wire wheel to remove any scale and flux from your new hole punch. You may need to sand or grind down the sharp or rough spots, if any... :-)
Step 6: Use Your New Hole Punch
Take care to grip; press; twist. I am able to cut about 10-15 at a time with this type of punch
Note that I melted my handle waaaaay tooooo much with the acetylene torch...so I ground it down and contoured it to fit.