Introduction: How to Make a Hole Punch by Repurposing a .357 Sig Shell (Bullet Cartridge)
Here is a way to repurpose those range cartridges that you just can't bear to leave at the gun range, after your monthly range practice!
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
The gun range is a great place to find one, if you do not own a .357 Sig; just go in and ask nicely...they reuse and/or sell the brass, due to its high cost; I imagine you can convince them to donate just ONE to your cause :-)
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)
You can remove the cap (the part which the firing pin compresses, causing the powder to burn), if you would like to have a clearance hole; by pressing a pin or other suitably slim item down the pin hole, you can clean the tobacco plugs from the cutter. Keep in mind that the later brazing step may ("will most likely") interfere with the clearance hole. :-)
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
Place the cartridge in a vice with VERY SOFT jaws....it is very thin brass after all :-)
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)
This is totally optional: you can (like me) demonstrate the awesome skill of brazing REALLY THIN brass, for the first time in more than two decades...(your results may vary...hopefully, it varies in a more skillful way that mine) :-)
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
Hopefully, if you choose to use a penny for the handle......you will use an OLD one..not one of the new aluminum ones like I did!
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
Thats it! Lets test it out!
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.
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